500 1 u]$VERSALCOUNTER-TIMER

INSTRUCTION, OPERATIONAND APPLICATION MANUAL

80-o1-oo371t88

GLOBAL SPECIALTIES1486 Highland Avenue, Unit 2Cheshire, CT 06410(203)272-3285Tel.(203)2724330Fpx

TABLE OF CONTENTS

5 0 0 1 S P E C I F I C A T I O N S . . . . p a g eINTRODUCTION . PageCONTROL LOCATIONS AND DESCRIPTIONS . . . . eageINITIAL INSPECTION AND CHECKOUT PROCEDURE ..PaqeOPERATING INSTRUCTIONS . ealeOPERATING MODES . . .PaqeS I G N A L C O N D I T I O N I N G . . . . e a i eDISPLAY HOLD/MEASUREMENT CYCLE DELAY . . page

EXTERNAL TIMEBASE . PageMAINTENANCE AND CALIBRATION .ea!eCASE DISASSEMBLY . .pageCASE REASSEMBLY . . .PaqeFUNCTIONAL DESCRIPTION . pa6eAPPLICATIONS . page

SERVICE AND WARRANTY INFORI\4ATION . Paqe

LTST OF ILLUSTRATIONS

FIGURE 1. Contro l Locat ions-Front Panel . . . . page 5FIGURE 2. Contro l Locat j -ons-Rear Panel page 10F I G U R E 3 . S i g n a l E x a m p l e . . . . p a g e 2 0F IGURE 4 . Fuse and T r immer Loca t i on . . . paqe 23F IGURE 5 . Case D isassemb ly /Reassemb ly .ea !e ZsFIGURE 6. B lock Diagram page 2 iF I G U R E ' 7 . P e r i o d A p p l i c a t i o n . . . . . p a g e 3 LFIGURE 8. T ime fnterva l Appl icat ion . . . page 32FIGURE 9. S ignal Condi t . ion ing Ci rcu i t . page 34FIGURE 10. Event Counter Appl icat ion . . . page 35

L4

t 1t 51_5L 82 L2 TZ J

Z J

z 6

2 8? n

3 7

ImpedanceResponseSensi t iv i tAttenuator

TNPIITS:

5OO1 SPECIFICATTONS

2 inputs, AFRONTA INPIIT:

B INPUT:

and B. DC coupled, BNC connectors1, llegohm // 25 pFDC to L0 MHz20 mV RMSX l , X L 0 , X L 0 0 s w i t c h

selectable

Slope Select

TriqgerRange

TriqqerRanqe

Impedance

Response

LeveI- 0 . 5 v t o + 0 . 5 v t i m e s

attenuator settingr is ing edge, fa l l ing edge

switch selectableMax. fnput

Voltaqe Xt- Atten:+ / -400v peak , DC to 30 kHz+ / -L00v peak , 30 kHz to l _OO kHz+/-20v peak, L00 kHz to l_ MHz+/-5v peak, 1_ MHz to 10 MHz

XLO At ten:+/ -400v peak, DC to L MHz+/-s9v peak, 1 MHz to LO MHz

XL00 A t ten :+/ -400v peak, DC to L0 MHz

Level

I r{egohm // 25 pFDC to 2 MHz20 nV RMSXl , X l -0 , XL00 sw i t ch

selectable

- 0 . 5 v t o + 0 . 5 v t i n e sattenuator sett ing

r is ing edge, fa l l ing edgeswi tch se lectable

1 M e g o h n / / 2 5 p F(1k above +5v or below 0vinput)LOO kHz to 1-0 MHz,

50 ns pulse width rninimun

Slope Select

Max. InputVoltage Xl_ Atten:

+/ -400v peak, DC to 30 kHz+/-LOOV peak, 30 kHz to LOO kHz+/-20v peak, L00 kHz to t MHz+/-IOv peak, L NIHz to 2 MHz

Xl-O Atten:+/-400v peak, DC to j_ MHz+/-J-OOv peak, I MHz to 2 MHz

Xl-00 At ten:+/-400v peak, DC to 2 MHz

L input, external t irnebase.DC coupled, BNC connector

fmpedanceResponseSensi t iv i tAttenuator

REAR PANEL

REFERENCE:

}IODES:

Inputne_gulrengnt

t'tax.-f nput--wtlese

Crystal Osci l latorFrerency@@Temperature

Stabi l i tv

Frequency

TTL levels

+20v , -L5v

MHzppn/year

+/-4 ppm, 5C to 35C

L0 MHz maxi 4 ranges wi thga te t i r nes o f O .OI /O .L /1 . .O/LO seconds; d isp lay inkHz; A input on ly400 ns to L0 sec ; 4 rangesw i th L / Io / too / tooo cyc leaverage; d isp lay inmicroseconds; A input on ly1 0 M H z r n a x i n t o A i n p u t , 2MHz in to B input ; 4ranges, counts cyc les at Ainput over L/Lo/ Ioo/LoOocycles at B input .2 0 0 n s t o l - 0 s e c ; 4 r a n g e sw i th 1 /Lo / t oo / tooomeasurement cycle average(one measurement cyclebeing the t irne intervalfrom the selected edge atthe A input to theselected edge at theB i n p u t ) .L0 MHz max;counts to99 ,999 ,999 i one range ; Ainput on ly .

+/ - ( t i rne base error Xfrequency) +/- l_ LSD. LsDdisp layed Loo/ ) ,o / I / o . IH z f o r o . o ) , / o . V L . O / L osecond gate t irnes+/- ( t i rnebase error Xper iod ) + / - ( ( t r i gge rerror*/cycles averaged) Xper iod) +/ - 1 LSD, LsDd isp layed l oo / Io / I / o . Ins fo r I / L0 /1 ,oo / Iooocycles averaged+/- l - LSD; LSD disp layed -I / o . I / o . o I / o . 0 0 L f o rL /LO/LOO/LOAO cyc lesaveraged

L 0<4

Period

Frequencv Rat io

Time Interval

Event Count

ACCTJRACY: Frectuencv

Period

Frequency Rat io

Tine Interval

Event Count

+/- ( t imebase error X t imeinterval) +/- A inputtrigger error* +/- B inputtrigger error* +/- L countper cycle averaged

- no inherent error; LSDdisplayed - l- count

CONTROI,S

DISPI,AY

POWER

DIITENSIONS

OPERATINGTE}TPERATT'RE

INCLUDES

* Note: Tr igger

power; 5 mode selector swi tches; 4 rangeselector swi tches; run; hotd; reset ; d isp laydelay; in ternal /external t imebase swi tch; p lustr igger Ievel, slope select, and attenuatorfor both A and B inputs

8 d ig i t , 7-segrnent O.43 inch LED disp lay;decirnal point indicates t ime in rnicroseconds,frequency in kHz; discrete LEDs indicateOVERFLOW (counter overf low) and GATE (gateopen) ; de lay feature var ies per iod betweenmeasurement cyc les f rom 75 msec to 7.5 secondswith DELAY control, detent posit ion holds nextmeasurement reading indef in i te ly

l -05 -L35 VAC, 57 -63 Hz , 10 VA max imum (ZL5-Z3OVAC, 50 -60 Hz ve rs ion ava i l ab le )

3 x LO x 7 inches H x W x D (76 x 254 x 1_78 rnrn)3 . 0 } b s ( 1 . 4 k g )

0C to 50C, ca l i b ra ted a t ZSC + / - 5C

instruction manual

error = pe?k-tg-pgak ngise vgltaqe on inputs ignal s lope ( in vo l ts per second)

INTRODUCTION

The nodel 5001- Universal Counter-T imer is des igned for theelectronic measurement and display of freguency, period, t ineinterval, and counted events. Both input channels feature ful1and independent signal condit ioning by mqans of attenuation,s lope se lect ion, and var iab le t r igger level . The var iab ledelay/hoId functj-on al lows the introduction of a delay betweenmeasurement cyc les of f rom 75 n i l l iseconds to 7.5 seconds, or theresul ts of a s ing le measurement can be d isp layed indef in i te ly .

Ease of use combine wi th rugged design to prov ide aninst rument that wi l l f i l l a wide range of requi rements.

FREQUENCY measurements can be rnade up to 10 ltHz, with acho ice o f d i sp layed reso lu t i on o f t -00 Hz , ) -O Hz , L Hz , o r O . i - Hzusing the gate t ines of 0 .01 seconds, 0 .L seconds, 1 second, or1.0 seconds.

PERIOD measurements are easi ly accompl ished cover ing therange f rorn 400 nanoseconds to L0 seconds. By se lect ing L, L0l -00 , o r 1 -000 cyc le ave rage , a reso lu t i on o f 100ns , L0ns , 1ns , o r0 .Lns i s ach ieved .

T h e r a t i o o f t h e f r e q u e n c y a t t h e A i n p u t c o m p a r e d t o t h a t a tthe B input is displayed by using the FREeuENcy RATro mode. Thenumber of cyc les averaged wi l l - detern ine the resolut ion, wi th upto th i rd dec imal p lace accuracy poss ib le us ing I -OOO cyc les.

The TIME INTERVAL mode wi l l measure the e lapsed t ime, f rom200 nanoseconds up to L0 seconds, between an edge occurr ing atthe A input and a separate edge at the B input . E i ther a r is ingor fa l l ing edge can be se lected for e i ther input , nak ing th ismode useful for measuring not only the t irne between events, buta lso for measur ing pulse widths.

When the EVENT COUNT mode is se lected, the 5OO1 wi l l d isp laythe number of edges, e i ther r is ing or fa l l ing, that appear at theA input. These events can occur at a rate of up to f.O MHz, andt h e c o u n t c a n b e f r o z e n o r r e s e t a t a n y t i m e b y m e a n s o f t h ef ront panel swi tches.

Using the rear panel EXTERNAL TIMEBASE INPUT providescapabi l i t ies such as extended resolut ion or automat ic scal ingbeyond that which is nornal ly avai lab le us ing the Frequency Rat iomode. This is , o f course, in addi t ion to the abi l i ty to connecta h igh-prec is ion 10 MHz c lock source i f h igher accuracy isrequi red than that o f the normal t imebase.

The many features and funct ions of the 5001, combined wi ththe br ight 8 d ig i t , 0 .43 inch LED disp lay wi th automat ic dec i rna lpoint placement and separate annunciators for gate-open andcounter-over f low condi t ions, resul t in a f lex ib i l i ty and ease ofuse that are appropr ia te for any counter- t imer demands, a I1 inone rugged and re l iab le inst rument .

- - - - = : - 1 - - - f f i 1 : r r r r F r

_ c Y c l . a t I I l o t t o o t l o o o t I ^ l l ^

FISAL COUNT

Figrure 1 - Control Locations - Front Panel

CoNTROI, LOCATIONS AI{p DESCRTPTTONS

(1) PwRPower switch. Push in this red pushbutton to turn the unit

ON, push again to re lease to OFF. The d isp lay wi l l I ight ,dependent upon the switch sett ings. If none of the otherpushbut tons are pushed in , the d isp lay wi l l be bIank.

(2 ' FREQ.This f irst gray pushbutton selects the Frequency Counter rnode

of operat ion. E i ther the r is ing or fa l l ing edge (as determinedby the set t ing of the sLoPE swi tch) of the s ignar appl ied to theA input wil l be counted during the gate t ine selected by thewhi te pushbut tons (e i ther .01, .1 , 1 ' , or l -0 seconds) , and wi r r bedisp layed in k i loHerLz wi th the appropr ia te dec imal po int . Themeasurernent range extends frorn DC to L0 MHz.

(3) PERToDThe second gray pushbutton selects the Period Deasurement

mode of operation. This measures the t irne that elapses from oner is ing edge to the next r is ing edge, or one fa t l ing edge to thenext fal l ing edge (as determined by the sett ing of the sl,opEswi tch) , o f the s ignar appl ied to the A input . This measurementcan be made for a s ing le cyc le, or for 10, LOO, or I -OOO cyc les(depending on the white pushbutton selected), giving a resolutionof L00ns, 1-0ns, lns, or O.Lns respect ive ly . The t i rne isd isp layed in microseconds, wi th the deci rn l l po int automat icat lyposi t ioned. Mul t ip le cyc le measurements are a isp layed as theaverage value of a single-cycle event. The measurement rangeextends f rom 40Ons to L0 seconds.

(4) RATrOThe third gray pushbutton selects the Frequency Ratio mode of

operation. The frequency of the signal present at the A input is

compared to the frequency at the B input, and the ratio of A/B isd isp layed. This can be accompl ished for 1 , 10, 100, or L000cycles at the B input (as deternined by the selection of thewhi te pushbut tons) , d isp lay ing the rat io wi th resolut ions out tothe th i rd dec inal p lace. E i ther the r is ing or fa l l ing edge canbe selected for both the A and B inputs. fnput frequencies canrange f rom DC to 10 MHz in to the A i npu t , and DC to 2 N lHz i n tothe B input.

(5) TruEThe fourth gray pushbutton selects the Tine Interval mode of

operation. The amount of t ine that elapses between a signal edgethat occurs at the A input and an edge at the B input ismeasured, and d isp layed in microseconds. In essence, the s ignalat A starts the t imer, and the signal at B stops it . Either ther is ing or fa l l ing edge can be se lected for both the A and Binputs, and the display can be the average of the result ofe i ther Lt 10, L00, or L000 A- to-B events (as determined by theselect ion of the whi te pushbut tons) . I t is inpor tant to note,however, that whereas the resolution wil l increase when morecycles are averaged, the accuracy of the reading does not. Thisis due to the inherent +/- 1 count uncertainty, coupled with thefact that the instrument actually takes an entirely newmeasurement for every A-to-B transit ion. There is therefore a+/- 1 , +/ - 10, +/ - L00, or +/ - l -000 count uncer ta in ty for the 1- ,10, l -00, and 1000 cyc le averages, and absolute reading accuracydoes not change. The Time fnterval mode is functional over a200ns to L0 second range.

( 6 ) conMrThe f i f th gray pushbutton selects the Event Counter mode of

operat ion. The inst rument wi l l d isp lay the number of r is ing orfa l l ing s ignal edges (detern ined by the set t ing of the SLOPEswitch) that occur at the A input. The rate can be up to 10 MHz,and the maximum count d isp layed before counter over f low is99,999,999. In the Event Counter rnode, the whi te pushbut tonsper forrn the fo l lowing funct ions:

(71 RUN. The f irst white pushbutton, whenpressed i n , w i l l a l l ow the 500L to d i sp lay , i nr e a l t i n e , t h e n u m b e r o f e v e n t s t h a t h a v e b e e ncounted. If the RESBT button had beenpressed, the d isp lay wi l l be c leared, wi thonly the rightmost decirnal point l i t , when RUNis selected. If the HOLD button had beenpressed in , se lect ing RUN wi l l update thedisplay from the frozen count to the presentcount and a l low real - t ime d isp lay of the countto continue.

(8) HOLD. The second white pushbutton providesa t td isp lay holdt r funct ion. When selected, theinstrument wil l freeze the count on thedisp lay, but the running count wi l l cont inueto accumulate. When the RUN button is pressed

in, the display wi l l cbange i rnrnediately toreflect the total count. If the RESET buttonis pressed, the internal counters wi l l c leart o z e r o , a n d t h e d i s p l a y w i l I c l e a r t o s h o wonly the rightnost decimal point.(9) RESET. The third white pushbutton wi1lreset the internal counters to zero and wiIIc lear the display. When pressed in, only ther ightmost decimal point wi t l be 1i t .

(7',) . Olll/RnNThis first white pushbutton affects the operation of the

instrument in the following way:In the Frequency Counter mode, the .OL second gate t ime

selected.In the Period, Frequency Ratio, and Tirne Intenral modes

operat ion, the d isp lay wi l l re f lect the measurement ofs ignals over a s ing le measurement cyc le.

i s

o fthe

In the Event Counter mode, the RUN function is selected;t h e 5 0 0 1 w i l l c o u n t s i g n a r e d g e s a n d d i s p l a y t h e t o t a r i nrea l t ime .

( 8 ) . L / L o / H o L DThe second white pushbutton affects the operation of the

inst rument in the fo l lowing way:rn the Frequency counter mode, the 0.L second gate t irne

is se lected.rn the Period, Frequency Ratio, and Time rntenral modes

of operat ion, the d isp lay wi r r re f rect the average s ignalva lue of a s ing le cyc le by measur ing ten cyc les and d iv id ingthe result by ten.

In the Event Counter mode, the HOLD function isserected; the 5001- wi l l cont inue to count s ignal edges, butt h e d i s p l a y w i l r n o t b e u p d a t e d u n t i l t h e R U N b u t t o n i spressed back in .

(e ( l/t_oolRESETThe third white pushbutton affects the operation of the

instrurnent in the fol lowing way:rn the Frequency bounter mode, the L.o second gate t ine

is se lected.rn the Period, Frequency Ratio, and Tine rnterrrar modes

of operat ion, the d isp lay wi r l re f lect the average s ignalv a l u e o f a s i n g r e c y c l e b y m e a s u r i n g o n e h u n d r e d c y c l e s a n ddividing the result by one hundred.

fn the Event Counter mode, the RESET function isse lected; the 5001- wi l l s top count ing, the in ternal counterswi l l c lear to zero, and the d isp lay wi r l b1ank, leav ing onlythe rightmost decirnal point l i t .

( 10 ) 10 l l oooThe fourth white pushbutton affects the operation of the

instrurnent in the fol lowing way:rn the Frequency counter mode, the L0 second gate t ime

is se lected.

In the Period, Frequency Ratio, and Tine Interrral rnodesof operat ion, the d isp lay wi l l re f lect the average s ignalva lue of a s ing le cyc le by neasur ing one thousand cyc les anddividing the result by one thousand.

Although it is not marked as such, this button alsoperforms the HOLD function in the Event Counter mode.

(11) A rNPrrrTh is BNC connec to r i s the i npu t tha t w i I I be used fo r a I I

measurements - alone when in the Freguency, period, and Eventc o u n t e r m o d e s , a n d i n c o n j u n c t i o n w i t h t h e B i n p u t w h e n i n t h eFrequency Ratio and Time fnterval modes.

(12) B rNPrrrT h i s B N C c o n n e c t o r w i l l b e u s e d f o r s i g n a l i n p u t s o n l y i n t h e

Frequency Ratio and Tirne rnterval modes of operation, and thenonly in conjunct ion wi th the A input . There are no c i rcumstanceswhen the B input wi t l be used a lone. r f the Frequency, per iod,or Event counter rnodes are selected, dDy signal present at the Binput wi l l be ignored. Under these condi t ions, i t is goodpractice to disconnect the signals to the B input, but i t is notessen t i a l t o do so .

(13) srpPEThese swi tches determine the s ignar edges, e i ther r is ing or

fa l l ing, that the 5001- wi l l use in the var ious measurement modes.T h e s e l e c t e d e d g e w i r r b e t h e o n e t h a t t h e i n s t r u m e n t u s e s t ocount , o t , in the T ime rntervar mode, wi l l be the s ignar thatstarts or stops the t irner.

(14) ATTEN.The ATTENuator controls are used to select the amount of

attenuation that the input signals receive before being countedby the 5001. rn the x l " pos i t ion, the fur l s ignar is passed tothe input stage of the instrument. when x10 is serected, thec o u n t e r s e e s a s i g n a l t h a t i s L / 1 0 t h t h e a m p l i t u d e o f t h eor ig ina l , and when in Xi -00, the s ignar is L / l -ooth the or ig ina l .This is usefur in obta in ing a s tabre and accurate count , forthere is o f ten noise present on a s ignal , and i f the lever of thes ignal is a t tenuated, so wi l l the noise be.

(15) TRIG. LEVELThe TRfGger LEVEL controls determine the voltage 1evel at

which the 500L wi l l recognize and count the input s ignar . wi ththe ATTENuator switches in the x3- posit ion, the range of thecontro l extends f rom -0.5 vo l ts to +0.5 vo l ts . Thetwelve orclock posit ion corresponds to a zero volt threshold,one o rc lock i s +0 .L vo1 ts , two o rc lock i s +o .2 vo r t s , and so on .The e leven orc lock posi t ion wi l l set a threshold of -0 .L voI ts ,ten orclock is -O.2 volts, and so on. When the ATTENuator switchis in the x1-0 posit ion, the tr igger 1evel range is from -5 voltst o + 5 v o l t s , a n d w h e n t h e A T T E N u a t o r s w i t c h i s i n t h e X t - O 0posi t ion, the range is f rom -50 vo l ts to +50 vo l ts . Thethreshord points continue to roughly correspond to crock

posit ions. using the ATTENuator and TRrGger LEVEL controlstogether wi l l a l low a wide range of s ignals to be rneasured, suchas_AC.super imposed on DC, log ic levels for TTL, EcL, and c i , Ios,and r ing ing or no isy d ig i ta l s ignals .

(16) DISPLAY

. The display consists of eight seven-segrnent LEDs with a 0.43inch character .he ight . Leading zeros are b lanked in a l l modes,1. ,d .dec ina1 points automat ica l ly d isp lay Freguency in k i loHer tz ,Period and Tirne rnterval in micioseconai, and Freiuency Ratio andEvent Count in units.

(17) GATEThe GATE LED l ights to indicate that a measurernent cycle is

in progress. rn the Freguency node, the LED wir l l iqht for o .o l - ,0 .1, 1 .0, or l -0 seconds, depending on the se lect ion of tne whi tep u s h b u t t o n s . T h e L E D w i l l b e o f f f o r a t i r n e b e t w e e n 7 5ni l l iseconds and 7.5 seconds, as determined by the set t ing of theDET,AY control. rn the period and Frequency Ratio modes, tne lnow i l l be l i t f o r t he du ra t i on o f t , 10 ; 1oo , o r Looo cyc i . espresent at the A input, depending on the sett ing of the whitepushbuttons, and be off for the duration of one cycle at the Ainput, or the t ime set by the DELAY control, whiclever is longer.rn the T i rne rnterva l - mode, the LED wi l l be r i t for t - , 10, Loo, o tL000 A- to-B t rans i t ions, depending on the set t ing of the whi tepushbut tons, and be of f for the durat ion of one e- to-a t rans i t ionor the t ime set by the DEl,Ay control, whichever is ronger. rnthe Event Count mode, the LED wil l be l i t continuously; t fr" DELAycontro l wi l l have no ef fect .

(18) OVERFTFWThe ovERFLow LED wirr l ight whenever the count exceeds

99999999. This wi l l occur , for example, when a f reguency overL 0 M H z i s i n p u t a n d t h e g a t e t i m e i s l - 0 s e c o n d s , o r w h e n - a t i r n einterval over LO seconds is measured with LOOO cycles averaged.

(le) DEraYThe DET,AY contror arrows the introduction of a time

between one reading and the next. This deray varies frommaximum of approximatery 7.5 seconds when thL control isc lockwise, to a minirnun of approxinatery 75 rni l l isecondscontrol is in the fuI1y countercrockwise - but before thedetent - posit ion. When the control is cl icked into the detentposi t ion, labeled HOLD, the 5001- wi l l take one measurement anddisp lay the resul ts indef in i te ly . This contro l a lso serves thefunction .of

I 'primlng" the instrument for single cycle events.F u r t h e r i - n f o r m a t i o n o n t h e u s e o f t h i s c o n t r o l c a n b e f o u n d i nthe OPERATING INSTRUCTIONS section.

delaya

fu l1ywhen the

INTERNAL O IMT---]O EXTERNALTIMEBASE

Fignrre 2 - Control Ipcations - Rear Panel

(20) TNTERNAL/EXTERNAL TIITEBASEThe INTERNAL/EXTERNAL TfMEBASE switch al lows the selection

of e i ther the in ternal Lo MHz reference, or an external ly appl iedreference within a freguency range of i-oo kKz to 10 yl[z. rf noexternal reference is present on the EXTERNAL TIMEBASE INPUTconnector, the switch MUST be in the TNTERNAL posit ion for the500L to funct ion. Use o- f an externaf t imebase can prov ide suchadded features as increased resolution, greater accuracy, andautomat ic scal ing. Fur ther d iscuss ion and examples can be foundiN the OPERATING INSTRUCTIONS and APPLICATIONS sections.

(21) EXTERNAL TIITiEBASE INptIIThis BNC connector is used as the input for an external

t imebase s ignar . The s ignar must be TTL 1ever , wi th a f requencybetween 100 kHz and l"o yrHz, having a rninimum pulse width of50 nanoseconds. r f the external t imebase is not in use, i t isgoog practice to disconnect any signar present at this BNc, buti t is not essent ia l to do so.

1 0

2 .

3 .

TNTTIAL INSPECTTON AND CHECKOIII PROCEDI'RE

In order to accompl ish the in i t ia l inspect ion of the 500L,the following is reguired:

l-. A grounded (three-prong) so/6o Hz AC outlet of the correctvol tage.A l -0 MHz s ine wave s ignal source of L00 rn i r l ivo l t RMSampl i tude, no DC of fset .A l -00 kHz s ine wave s ignar source of LOo mi l r ivo l t RMSampl i tude, no DC of fset .A l- MHz TTl,- level signal source.

Note signal levels for i terns 2 and 3 above are not cri t ical.However, i f dif ferent arnpli tudes are used, the ATTENuator andTRrc LEVEL sett ings outrined in the forlowing wil l have to beadjusted accord ingly .

PROCEDI'RE

l-. Plug the 5001- into the outlet. Select the Freguency Countermode and the .0L second gate t i rne ( the f i rs t wni tepushbutton). Turn the DELAy contror to ninimum (fulrycounterc lockwise, but before the detent IHOLD] pos i t ion) .select the TNTERNAL TTMEBASE from the rejr paner. Turnpohrer oN - the d ispray should now r ight , showing .o on ther ight .

2. Connect the l-0 yIHz signal source to the A input. Switch theA input ATTENuator to XL. set the A input tnrc LEVELcontro l to the L2 orc lock posi t ion - the d isp lay shourd nowread L0000.o, indicating the frequency in ki loH-ertz, and theGATE LED wi l l f lash rapid ly .

3. Select the .L second gate t i rne ( the second whi te pushbut ton)- the d isp lay wi l l ch lnge to 1oooo.oo. Note that the GATELED f lashes more srowly, re f lect ing the longer gate t i rne.

4 - Se1ect the l- second gate t irne (the third white pushbutton)the d isp lay wi l l change to I -OOOO.OOO, and when tne 6ATE LEDl ights i t w i l l be on for one second.

5. Select the L0 second gate t ine (the fourth white pushbutton)- the d isp lay wi l l ch lnge to Loooo.oooo. The GATE LED wir ln o w s t a y o n f o r t e n s e c o n d s a s t h e m e a s u r e m e n t i s b e i n gmade .

6. Rotate the DEr,Ay contror to i ts furl clockw j_se posit ion -note that the "offfr t ime of the GATE LED (the t ime betweenmeasurernents) increases to at least 7 .5 seconds. Return thecontrol to i ts previous (countercrockwise - before thede ten t ) pos i t i on .

4 .

Lt_

7. Connect the L MHz TTL-IeveI signal to the EXTERNAL TfMEBASEINPUT BNC on the rear panel. Switch the INTERNAL/EXTERNALTTMEBASE switch to the EXTERNAL posit ion. select the .1second gate t i rne - the d isp lay should now read t o0ooo.oo.No te tha t t he GATE LED now l i gh ts fo r j - second , and the t imebetween measurements is approxinately L.5 seconds. Returnthe TNTERNAL/EXTERNAL TTMEBASE switch to the TNTERNALposit ion and disconnect the signal going to the EXTERNALTIMEBASE INPUT BNC.

8. connect the 1,00 kHz signar to the B input. switch the Binput ATTENuator to the Xl- posit ion and set the B input TRIGLEVEL contro l to the J .2 o 'crock posi t ion. serect theFrequency Ratio mode, 1 cycle averagle (f irst whitepushbut ton) . The d isp lay should now read t_OO.

9. serect in order the 10, l -oo, and Looo cycre averages ( thesecond, third, and fourth white pushbuttons) - the disprayw i l l change to read i -OO.O, 1OO.OO, and LOO. 'OOO,respect ive ly .

l -0 . Disconnect the s ignars going to the A and B inputs. connectthe L00 kHz signal to the A input and serect the periodmode. The d isp lay wi l l read 10.Oo0O microseconds and theGATE LED wi l l f tash rapid ly .

1 l - . se lect in order the Loo, 10, and l - cyc le averages. Thed isp lay w i l l change to read LO.OOO, 10 .00 , and L0 .0microseconds, respect ive ly . The GATE LED wir l be on toobrief ly to be seen in the t_O and L cyc1e averages.

12. se lect the Event counter mode. The d isp lay wi l l c lear andimmediately begin to show the accurnulating- count. The GATELED w i l l be I i t .

L3. Press in the HoLD (second whi te) pushbut ton - the d ispraywi l l r r f reezerr r but the sooL wi r l i t i - r r be accumurat in-gcounts in ternal ly . The GATE LED wi l l remain l i t .

] -4 . Press in the RUN ( f i rs t whi te) pushbut ton - the readigg wi r lc h a n g e t o u p d a t e t h e c o u n t , a n d w i l l s h o w t h e c o u n taccumulat ing. r f the count has been in progress for morethan 100 seconds, the OVERFLOW LED wi I I be l i t .

L5. Press in the RESET ( th i rd whi te) pushbut ton - the d ispraywi l l c lear , showing only the r igh lmost dec imar point , - an lthe GATE LED wi I I not be l i t .

l -6. Press in the RUN pushbutton - the counting wirl begin againfrorn zero.

L7. connect the l-00 kHz signar to both the A and B inputss imul taneously . Select the T ime fnterva l mode. Swi tch theA input sLoPE switch to the rising edge (r iqht-hand side)p o s i t i o n a n d t h e B i n p u t s l , o p E s w i t c h t o t h e f a l l i n g e d g e

I 2

( left-hand side) posit ion. Set both TRIG LEVEL controls totheir L2 orclock posit ions. select 1- cycle average - thedisp lay should ind icate approx imate ly 5.0 microseconds.

l -8 . Select in order the 10, L00, and l -000 cyc le averages. Thed isp lay w i l l change to read 5 .00 ' 5 .000 , and 5 .0000microseconds, respectively. Sorne instabil i ty nay be notedin the readings as more cycles are averaged; this is normal,as i t ref lects the +/- L count error that exists for eachcycle when in the Tirne Interval mode.

i-9. Slowly rotate the A input TRIG LEVEL control clockwise - thereading wi l l decrease unt i l the d isp lay ind icatesapproximately 3 microseconds, at which point measurementsw11f cease. Rotating the control back counterclockwise wil lrestart the rneasurements, and the readings wil l increase toapprox imate ly 7 microseconds at which point measurementswi l l again cease. Return the contro l to the L2 orc lockpos i t i on .

Repeat step L9 using the B input TRIG LEVEL control i theresul ts should be ident ica l .

2 0 .

2L. Change the A input SLOPE swi tch to the fa l l ing edge ( le f t -hand side) posit ion and the B input sLoPE switch to ther is ing edge ( r ight -hand s ide) pos i t ion. Repeat s teps L9 and20. The TRIG LEVEL controls wil l now cause the readings toincrease when they are rotated clockwise, and decrease whenthey are rotated counterclockwise.

This concludes the in i t ia l inspect ion and checkout of the 5001- .

NoTE: If no frequency sources are available, a rudirnentary testof bas ic inst rument funct ionabi l i ty can be accompl ished us ing thebui l t - in SELF-TEST mode, the procedure for which fo l lows. Thisi s b y n o m e a n s a t h o r o u g h t e s t , b u t i t w i l l v e r i f y p r o p e roperation of some internal logic and counting functions.

With power turned ON, press in both the Frequency and Periodmode pushbut tons. Se1ect the .0L second gate t ime ( f i rs twhite pushbutton), INTERNAL timebase, and minimum DELAY(control fuI1y counterclockwise, but before the detent)the d isp lay wi l l ind icate l -o0o0.o regard less of the set t ingof the ATTENuator switches, TRIG LEVEL controls, oF SLOPEse lec to rs .

Rotate the DELAY control to i ts fuII clockwise posit ion -

note that the rroffrr t ime of the GATE LED (the t ime betweenmeasurernents) increases to at least 7.5 seconds. Return thecontrol to i ts previous (counterclockwise - before thede ten t ) pos i t i on .

1 " .

2 .

1 3

3. Select in order the .L , L t and L0 second gate t ines. Thed i s p l a y w i I l r e a d l - 0 0 0 0 . 0 0 , l - O O O O . O O O , a n d O 0 O O . 0 O O O ( w i t hthe OVERFLOW LED l i t), respectively.

This concludes the SELF-TEST checkout procedure.

t 4

OPERATING TNSTRUCrIONS

Because of the tremendous functionar versati l i ty of the5001- , these inst ruct ions wi l l t reat each of the features of th isinstrunent individually. There is f irst presented a descript iono f h o w t o u s e e a c h o f t h e o p e r a t i n g r n o d e s , t h e n a d i s c u s s i o h o fhow to adjust the signar condit ioning at each of the inputs,f o ] l o w e d b y a d e s c r i p t i o n o f t h e u s e o f t h e D i s p l a yHold/Measurement cycle Delay feature, and f inalry the use of theExternal Timebase Input.

OPERATING IITODES

Freguency CounterTo make a frequency measurement:

L. select the TNTERNAL timebase from the rear paner.2. Turn power oN by pressing in the red pwR pushbutton.3 - serect the Freguency counter mode by pressing in the

FREQ (f irst grly) pushbutton.4. Set the DELAY contro l to min i rnum ( fu l ly

counterc lockwise, but before the detent) .5 . c o n n e c t t h e i n p u t s i g n a r t o b e m e a s u r e d t o t h e A

input BNC. Fol low the Signal Condi t ion inginst ruct ions, be low.

6 . S e l e c t a g a t e t i m e o f . 0 1 _ , . 1 , I , o r L 0 s e c o n d s , a sdes i red , t o ob ta in a reso lu t i on o f LOO Hz , LO Hz ,1, Hz, oF 0.1_ Hz, respect ive ly . The d isp lay wi l lindicate the frequency in ki lottertz.

7 - The GATE LED wil l be on during measurement cycles andoff between measurement cycles. Actual measurementra te i s de te rn ined by the sum o f t he GATE t i r neselected, the DEr,Ay t irne selected, and a f ixed amountof display latch rrhousekeepingfl t irne.

8. The OVERFLOW LED wil l l ight in the Frequency Counterrnode onry when a frequency of 1-0 MHz or greater ismeasured us ing a GATE t ime of LO seconds.

PeriodTo rnake a period measurement:

L. select the TNTERNAL timebase from the rear paneI.2- Turn power oN by pressing in the red pwR pushbutton.3. serect the per iod rnode by press ing in the pERroD

(second gray) pushbutton.4. Set the DELAY contro l to rn in imum ( fu l ly

counterc lockwise, but before the detent) .5 . c o n n e c t t h e i n p u t s i g n a l t o b e m e a s u r e d t o t h e A

input BNC. Follow the Signal Condit ioninginst ruct ions, be low.

6. Select whether the rneasurement wil l be taken everycyc le or averaged over 10, l_OO, or I_OOO cyc les. Theresul t ing resolut ion wi l l be 3_00 ns, 10 n i , 1 nsr orO.1 ns, respect ive ly , and the d isp lay wi l l ind icatethe period in nicroseconds.

l_5

7. The GATE LED wil l be on during measurement cycles andoff between measurement cycles. Actual measurementra te i s de te rm ined by the sum o f t he to ta l pe r iod o fthe selected number of input signal cycles, theDELAY tirne selected, and a f ixed amount of displayIatch rrhousekeepingtt t ine.

8. The OVERFLOW LED wil l- l ight in the Period rnode whent h e p e r i o d m e a s u r e d i s e q u a l t o o r g r e a t e r t h a nL0 seconds, L second, 100 rn i l l iseconds, orl -0 rn i l l iseconds for l , 10, l -00, or l -000 cyc lesaveraged, respectively.

Frequency RatioTo make a freguency ratio measurement:

L. Select the fNTERNAL tirnebase from the rear panel.2. Turn por{rer ON by pressing in the red pWR pushbutton.3. Select the Frequency Ratio mode by pressing in the

RATIO (third gray) pushbutton.4. Set the DELAY contro l to min imum ( fu l ty

counterc lockwise, but before the detent) .5. Connect the input signal with the higher frequency to

the A input, and the Lower frequency signal to the Binput . Fo1low the Signal Condi t ion ing inst ruct ions,below. Note i f des i red, the h igher f requencysignal may instead be connected to the B input. Thiswi l l resul t in a d isp lay of less than t - . Bear inmind that the avai lab le resolut ion is lessened whenused in th is conf igurat ion.

6. Select whether the measurement wil l be taken everycycIe, or averaged over 10, l_00, or L000 cyc les. Theresul t ing resolut ion wi l l be in whole uni ts , or tothe f i rs t , second, or th i rd dec i rna l p lace,respect ive ly , and the d isp lay wi l l ind icate thenumerical rat io of the A input frequency divided bythe B input frequency.

7. The GATE LED wi l l be on dur ing measurement cyc les andoff between measurement cycles. Actual measurementra te i s de te r rn ined by the sum o f t he to ta l pe r iod o ft h e s e l e c t e d n u m b e r o f i n p u t s i g n a l c y c l e s a t t h e Binput, the DELAY tirne selected, and a f ixed amountof d isp lay la tch r rhousekeeping" t ime.

8. The OVERFLOW LED wiII l ight in Frequency Ratio rnodewhpn the qa t i o me-asu red i s_equa l t o o r g rea te r t hanL o o / L , L o t / L , L o o / L , o r l _ o " / r f o r l - , 1 0 , 1 o o , o r l - 0 0 0cycles averaged, respectively.

Tine IntenralTo make a t ime interval measurement:

l-. Select the INTERNAL timebase from the rear panel.2. Turn power ON by pressing in the red PWR pushbutton.3. Select the T ine In terva l mode by press ing in the TIME

(fourth gray) pushbutton.4. Set the DELAY control to rninimum (ful ly

counterc lockwise, but before the detent) .5a. f f the e lapsed t ime between two separate events is

1 6

to be rneasured:L . Connec t t he s igna l t ha t i s t o s ta r t t he t im ing

sequence to the A input. Determine whether arising or faLl ing edge is appropriate and setthe A input SLOPE switch accordingly.

2. Connect the signal that is to terminate thetiming sequence to the B input. Deterrninewhether a r ising or fal l ing edge is appropriateand set the B input SLOPE switch accordingly.

3. Fol low the Signal Condi t ion ing inst ruct ions,below, for proper sett ing of the controls otherthan the SLOPE switches.

5 b . I f t h e p u l s e w i d t h o f a s i n g l e s i g n a l i s t o b emeasured:

L. Connect the signal to both the A and B inputss imul taneously .

2a. I f the r rh ighrr t ime of the s ignal is to bem e a s u r e d , s e t t h e A i n p u t S L O P E s w i t c h t o t h er is ing ( r ight -hand s ide) pos i t ion and the Binput SLOPE switch to the fal l ing ( left-hands i d e ) p o s i t i o n .

2b. I f the r r lowrr t i rne of the s ignal is to bemeasured , se t t he A i npu t SLOPE sw i t ch to thefa l l ing ( Ie f t -hand s ide) pos i t ion and the Binput SLOPE switch to the rising (r ight-hands i d e ) p o s i t i o n .

3. Fol1ow the Signal Condi t ion ing inst ruct ions,below, for proper set t ing of the contro ls otherthan the SLOPE switches.

6. Select whether the measurement wi l l be taken forevery A- to-B t rans i t ion, or averaged over 10, LOO, or1-000 such events. The resul t ing resolut ion wi l l beL00 ns , L0 DS, L DS, o r 0 .L ns , respec t i ve l y , and thedisp lay wi l l ind icate the t ine in terva l (or pu lsewidth) in microseconds. For s ing le, non-recurr ingevents, set -up the 5001- as fo l lows:

a. Select L cyc le average ( the f i rs t whi tepushbut ton) .

b. Rotate the DELAY control ful ly counterclockwiseto the HOLD (detent) posit ion.

c . Rotate the DELAY contro l s l ight ly c lockwiseunti l a rrcl ickrr is heard. This should be theminimum posit ion, before the detent. The GATELED should now be on. This indicates that the5001- is r rpr inedrr , ready to measure and d isp laythe f i rs t A- to-B t rans i t ion.

For mul t ip le , recurr ing events, i t is not necessary torrprimett the instrument; simply select the desired numberof cyc les averaged.7. The GATE LED wil l be on during measurernent cycles and

off between measurement cycles. The measurementcyc le begins wi th the f i rs t se lected ( r is ing orfal l ing) edge at the A input, and ends with the l-st,l-Oth, 1o0th, or l-000th selected edge at the B input.

L 7

Actua1 measurement rate is deterrnined by the sum ofthe measurement cycIe, the DELAY time selected, anda f ixed amount of display latch rrhousekeepingtt t ime.

8. The OVERFLOW LED wiII l ight in the Tirne Interval rnodewhen the interval measured is equal to or greaterthan 10 seconds, l - second, l -00 mi l l iseconds, orL0 n i l l i seconds fo r L , 10 , LOO, o r 1OOO cyc lesaveraged, respectively.

Event CounterTo count the quantity of a number of events:

L. Select the INTERNAL timebase from the rear paneI.2. Turn poii /er ON by pressing in the red PWR pushbutton.3. Se1ect the Event Counter mode by pressing in the

COUNT (f i f th gray) pushbutton.4 . Connec t t he i npu t s igna l t o be measured to the A

input BNC. Fol low the Signal Condi t ion inginst ruct ions, be low.

5. Press in the RESET ( th i rd whi te) pushbut ton. Thiswi l l c lear the d isp lay, leav ing only the r ightmostdecinal po int l i t . Th is a lso c lears aI I in ternalcounters to al low the count to begin from zero.

6. When prepared to begin counting events, press in theRUN (f irst white) pushbutton. The display wil lfol low the running count, that is, the number ofselected edges that have appeared at the A input.

7. The OVERFLOW LED wil l l ight in the Event Counter rnodewhen the count exceeds 99,999,999. Addi t ional countswil l continue to be displayed with the OVERFLOW LED1 i t .

8 . To f reeze the d isp lay, yet have counts cont inue to beaccumulated internally, press in the HOLD (secondwhite) pushbutton. pressing in the RUN pushbuttonwi l l i rnmediate ly update the d isp lay to the currenttotal of events counted. If the count had exceeded99,999,999 whi l -e in HOLD, the OVERFLOW LED wi I I l ightwhen the RUN pushbutton is pressed in.

9. To s tar t a new count , re turn to s tep 5.

SIGNAL CONDITIONING

Extensive signar condit ioning on both the A and B inputs isavai lab le on the 5001 to ensure maximum f lex ib i l i ty and accuracy.To der j -ve the fu I I benef i ts o f these features, the for lowingguidelines and recornmendations are offered:

AttenuatorDetermine the voltage Ieve1s of the signals being applied tot h e A a n d B i n p u t s .

For input signals greater than 2 volts RMS, set theAt tenuator to the X100 posi t ion.For input s ignals between 0.5 and 2.5 vo l ts RMS, set theAt tenuator to the X10 posi t ion.For input signals less than t- volt RMS, set the

1_8

Attenuator to the XL posit ion.Note that the above ranges overlap. Note also that theTrigger Level control range is affected by the Attenuatorset t ing (see below)The above sett ings are guidelines only; much depends on thecharacter is t ics of the s ignar being measured. Keep in mind,however, that high-amplitude signals may tend to overloadthe f ront -end c i rcu i t ry of the 5001_, especia l ly in the Xt_At tenuator pos i t ion. This wi l l not do any damage (as longa s t h e l e v e l s d o n o t e x c e e d t h e m a x i m u m s l i s t e d i n t h esPEcrFrcATroNS), but the instrument nay not respond to inputs ignals . As a genera l ru le , the maximum arnount ofa t t e n u a t i o n t h a t c a n b e u s e d - a n d s t i l l a I l o w t h e 5 0 O t - t orespond - is the best choice. This wi l l a lso at tenuate anynoise that is present on the s ignal to the extent poss ib le ,thus helping to ensure stable and accurate readings.

Trigger LevelThese controls, one for the A input and one for the B input,determine the vortage lever which the input signal rnustcross for the 500L to recognize the s ignal . Used inconjunct ion wi th the At tenuator , they a l low the measuremento f A C s i g n a l s s u p e r i r n p o s e d o n D C , a n d t h e p o i n t a t w h i c hdig i tar s ignals t r igger the 5oot- in ternar c i rcu i t ry . Therange of these contro ls are as fo l lows:

- Wi th the At tenuator in the X1- pos i t ion: +/ - 0 .5 vo l ts- Wi th the At tenuator in the X10 posi t ion. +/ - 5 vo l ts- Wi th the At tenuator in the X1-OO posi t ionz +/ - 50 vo l ts

N o t e t h a t p r o b l e r n s m a y a r i s e w i t h A C s i g n a r s r i d i n g o n a D Clever i f that DC revel is unstable; these problerns can beavoided by p lac ing a capaci tor in ser ies wi th the inputs ignal (between the s ignal source and the 5OO1 input l .s imi lar ly , a capaci tor may a lso be necessary i f the s ignalto be melsured is a compaiat ive ly Iow ampl i tude r id ing-on alarge DC level .The levels set by these controls roughry correspond to aclock face. For example, with the Attenuator in the Xi-oposi t ion, the L2 orc lock posi t ion wourd set a t r igger levelof O voI ts , L orc lock would set a l_ vo l t IeveI , 2 orc lockwould set a 2 vo l t leve l , and so on. MovingcountercLockwise, the l_ i_ orc lock posi t ion would set at r igger leve1 of -1- vo1t , l_O otc lock would set a -2 vo l tI e v e l , a n d s o o n .

Slope SelectorThese controls, one each for the A andwhether the r is ing or fa l l ing edges of

B inputs, determinethe input s ignals

w i l l be recogn ized by the 5OOL.- To se lect the r is ing edge, s l ide the Slope swi tch to the

r ight .- To se lect the

the l e f t .fa l l ing edge, s l ide the Slope swi tch to

In the Frequency, Period, and Frequency Ratio rnodes, thesett ing of these switches may not seem to matter. However,i f one edge of the s ignal(s) is nois ier than the other, best

L 9

performance wil l be realized if the instrument is set totrigger on the rrcleanerrt edge.r n t h e E v e n t c o u n t e r m o d e , t h e s e l e c t i o n o f t h e s l o p e w i l rdepend on the s ignar tha t i s to be counted , i .e . , i i tneoccurrence of the event is marked by a rising edge, then theslope switch should be set to the right; conversely, if theevent generates a falring, or negative-going, edge, then theSlope switch should be set to the 1eft.The setting of the Slope switches in the Tirne Interval modewill depend on the intended use:

- When the elapsed tine between separate signals on the Aa n d B i n p u t s i s t o b e m e a s u r e d , t h e s w i t c h e s m u s t b e s e tto reflect the siqnals that represent the start and stopt imes. For.example, i f a s ignir wi th a fa l r ing

"dge i ; -

t h e s t a r t s i g n a l a n d a s i g n a r w i t h a r i s i n g e d g e i s t n es t o p s i g n a l , t h e n t h e A i n p u t s r o p e s w i t c h h u s t b e s e tto th_" fall ing (left-hand side) position and the B inputmust be set to the r is ing (r ight-hand side) posi t ion.

- w h e n t h e p u l s e w i d t h o f a s i g n a r a p p r i e d t o t t r e a a n d Binputs simurtaneousry is to be neatured, the setting ofthe Slope switches wil l determine whether the f 'high;' orfrlohrrr t ime is displayed. To measure the tirne the signalis high, set the A input slope switch to the rising(r ight-hand.side) posi t ion, and the B input s lope Jwitchto the fa l l ing ( Ief t -hand side) posi t ion. to measuret h e t i n e t h 9 s i g n a r i s r o w , s e t t h e A i n p u t s r o p e s w i t c hto the fa l l ing ( lef t -hand side) posi t ion, and the Binput.srope switch to the r is ing (r ight-hand side)pos i t ion .

The fol lowing exanpre wi l r herp to crar i fy the use andimportance of the s ignal condi t ioning controls:

Figure 3 - Signal Exanple

_ rn f igure 3, above, i t can be seen that the r ising edge isslow and noisy, and there is considerabre r inging when thevoltage goes to zero. Assume that a freguency measurement isdesi red. rn th is case, the best po int to t r igger is on thefal l ing edge at approxirnatery the 3 volt tevet. This can beaccomplished on the 5OOl- by sett ing the Attenuator switch to thexl-O posit ion, sett ing the Trigger Level control to the 3 o'clockposi t ion, and set t ing the srope swi tch to the fa l l ing ( le f t -handside) pos i t ion. These set t ings wi l l a l1ow accurate and stabLereadings to be easi ly obta ined.

2 0

As can be seen, knowing the characteristics of the waveformto be measured greatly sirnplif ies the setting of the signarcondi t ioning controls. I f i t . is not possible to ascert i in thesecharacteristics, the best approach woutd be to start with themaximum amount of attenuation and slowIy rotate the Trigger Levelcontrol back and forth unti l a reading is disprayed. Decreasethe Attenuator. setting if necessary. When a reading is obtained,try both positions of the Slope switch to determine which givesthe best resul ts.

DTSPIAY HOLD,/UEASI'RET,IEIfT CYCLE DELAY

Under some condi t ions, the 500L wi11 make measurements andd i s p l a y t h e n a t a r a t e t h a t i s m u c h t o o f a s t t o r e a d o r f o l r o w .For this reason, a delay circuit has been incorporated which, atthe end o f each measure rnen t cyc l . e , de rays the s la r t o f t he nex tcycre by 0.075 to 7.5 seconds. This deray t ine is set by thefront-panel Delay control-. When the contiol is fu1ly clockwiseto the posi t ion marked MAx, the delay t ime is at i ts -maximum;yh,en ful ly counterclockwise (but before the detent posit ion), thedelay wi l l be min imurn. Dur ing th is t ime, the resul ls o f the mostrecent measurement cyc le remain d isp layed. fn i t ia l set -up of theinstrument is best aCcornplished uy slari ing with the rninirnundelay and rotat ing the contro l c lockwise unt i t the desi red amountof de lay is obta ined.

The detent pos i t ion of the Delay contror , marked HOLD,perrnits one measurement cycle to be cornpleted, then delays thestart of the next measurement indefinitLfy. This can be usefulfor unattended testing, such as measuring the period of aspurious transient event. Another use wourd b; to neasure theper iod of the f i rs t pu lse generated by an astabre osc i l ra tor ;o f ten the f i rs t pu lse width or per iod d i f fers s ign i f icant ly f romthe pulses fo l lowing.

Note that, when in the Hord posit ion, changing the mode orthe gate t ime/cycles averaged wil l init iate a new rneasurementcycle. Note also that the Deray control has no effect when inthe Event Counter mode.

EXTERNAL TTIiMBASE

The External Timebase feature greatry enhances thef lex ib i l i ty o f the 5ool - . By choosing the appropr ia te t i rnebase,the instrument can be conf igured to display- in

-non-standard units

of measure, increase the measurement acluracy, or extend therneasurement ranges in some modes.

Note: Do not se lect the External T imebase unless a TTL- leveIs i g n a l i n t h e r a n g e o f i - o o k H z t o t - o M H z i s p r e s e n t o n t h eExternal Timebase rnput BNC. rf no signal i l present, thedisp lay wi l r . not scan, and one d ig i t wi r r be dn constant ly .Leaving the instrument in this conait ion f i i11 darnage thedisplay. Also keep in mind that the display scanning rate

21"

is a function of the timebase frequency; at lower timebasefreguencies, and particularly berow soo kKz, the scanningact ion wi l l be obvious. fn addi t ion, the internalrrhousekeepingrr t imes are arso a function of the timebasefreguency, so some additional delay between measurementcycles wi l l be not iced.

The external i, imebase freguency required to allow for thedisplay of d i f ferent uni ts of measurement can be calculated bymeans of the fo l lowing formula:

fEx = t0 X 1ur /up)where

fpx = external t inebase frequency in MHzu" = selected units of measurementri = desired units of measurement

For example, i f i t is desired to display in cycles perminute when in the Frequency mode in the 1 second gate tirne:

f g x = 1 0 x ( L / 6 o )= . L 6 6 6 6 7 Y I H z ( L 6 6 . 6 6 7 k H z )

The selection of this t irnebase frequency wil l cause thedisplay to indicate in cycles per minute. when the i. second gatetirne pushbutton is selected in this case, the actual gate t irnew i l l b e 6 0 s e c o n d s . N o t e a l s o t h a t t h e d e c i m a l p o i n t w i l I s t i l lind icate the thousands posi t ionr So that i f , for exarnple, a 6o Hzsignal was appl ied to the A input wi th th is external L imebase,the d i sp lay wou ld read 3 .600 .

I f a n a c c u r a c y g r e a t e r t h a n t h a t w h i c h i s s t a n d a r d o n t h e500L is regui red, a prec is ion TTL- leveI s ignal source can be usedas an external t imebase. Sui tab le osc i l la tors are avai lab le f roma nunber of sources, some even being phase- Iocked to wwV s ignals ,giving extreme accuracy.

Extended ranges can be realized using the same reasoning asthat descr ibed in changing uni ts of measure. rn th is case,however , decade d iv isors of 10 MHz are recommended to s inpr i fyin terpretat ion of the d ispray. Again, an exampre wi l r herp ml tceth i s c lea r :

To achieve the capabil i ty of measuring t irne intervals of upto L000 seconds before overf low, use a t inebase frequency ofL 0 0 k H z . T h i s w i l l a r l o w a t i m e o f o v e r L 6 r n i n u t e s t o b emeasured directry in the l- cycre average posit ion. Note,however , that the resorut ion wi l r be decreased, in th is case tol -0 microseconds, and that the posi t ion of the decimal po int wi l lbe unchanged f rom normal ( in ternal t imebase) condi t ion l , and wi l ltherefore no longer reflect the normal units.

2 2

ITIAII{TENA}ICE Al{D CALIBRATION

Fuse Replacement

The 500L uses one fuse, type 3AG, L/4 amp slow-blow Q-/8 anpin 230 vol t uni ts) , 25O vol t . I t is rnounted to a connector onthe printed circuit board inside the case, toward the rear, nearthe power cord (see f igure 4, below). I f replacement of the fusebecomes necessary, follow this procedure:

L. Disconnect anything plugged into either the A or B input.2. Make certain the Power switch is OFF.3. Disconnect the power cord at the AC outlet.4. Open the case, following the instructions under CASE

DISASSEMBLY conpletely.5. Use a non-conductive fuse handling tool to safely remove the

o l d f u s e , a n d t o r e p l a c e i t w i t h a n e w o n e o f e q u a l s i z e a n drat ing.

6. Close the case, following the instructions under CASEREASSEMBLY (below) conpletely.

7. Reattach the power cord to the AC outlet.

The 500L is again ready for use.

Figure 4 - Fuse and Trimmer Location

Recalibration

The 5001- was ca l ibrated at the factory fo l lowing a burn- incycle just previous to shipnent; i t is warranteed to rneet orexceed i ts publ ished speci f icat ions. f f a t any t ime thecalibration becomes suspect, i t is recommended that theinstrurnent be returned to the factory for recalibration to ourstandards (traceable to the National Bureau of Standards). Fordetails, see FACTORY SERVICE AND REPAIR.

If f ield recalibration is preferred, the fol lowing equiprnentis requi red:

- A signal source, preferably L0 MHz, with an outputampl i tude between 200 n i l l ivo l ts and 2 vo l ts RMS, and anaccuracy of 0.4 ppm or better.

- A non-conductive, non-inductive tuning too1.

FUSE3 AG-1/2 A

OrnrrtrnrER CAp

It t-ZTRANSFORMER

2 3

1 , ,2 .3 .4 .

5 .

The procedure is as fol lows:Remove any connections from both the A and B inputs.Make certain the Power switch is OFF.Disconnect the power cord at the AC outlet.Open the case, fol lowing the procedure under CASEDISASSEMBLY completely.Locate the crysta l osc i l la tor t r immer capaci tor (see

f i g u r e 4 ) .NOTE:

In the fol lowing ste[E-, power wil l be appliedand circuitry wil l be exposed.

TTARIIINGPOTENTIALLY DANGEROUS OR LETHAL VOLTAGES ARE PRESENTWHEN POWER IS APPLIED TO THIS INSTRUMENT WITH CIRCUITRYEXPOSED. USE EXTREME CAUTION. AVOID ALL CONTACT WITHrHE CTRCUTT BOARD, EXPOSED COMPONENTS, AND EXPOSEDWIRING.

6. Turn on the precision signal source and connect i t to the Ainpu t o f t he 500L .

7. Turn the 5001- ON by pressing in the Power pushbutton.8. Select the Freguency Counter mode by pressing in the FREQ

(f i rs t whi te) pushbut ton.9. Set the Delay contro l to rn in imum ( fu1 ly counterc lockwise,

but before the detent) .L0 . Se lec t a ga te t ime o f . 01 seconds .l - L . A l l o w b o t h t h e s i g n a l s o u r c e a n d t h e 5 0 0 1 - t o o p e r a t e a t

least one hour .12. Observe the d isp lay on the 5O0l- ; i f i t reads 9999.9 or

L 0 0 0 0 . 0 o r l - 0 0 0 0 . 1 - , p r o c e e d t o s t e p L 5 .13. Adjust the Attenuator, Slope, and Trigger Level controls

(see OPERATING INSTRUCTIONS) for a stable reading. If thed i sp lay now reads 9999 .9 , L0000 .0 , o r 10000 .L , p roceed tos t e p 1 5 .

L4. Using the tun ing too l , ad just the t r inmer capaci tor unt i ]t he d i sp lay reads L0000 .0 .

1-5. Se1ect a gate t ime of .1 seconds.l -6 . Observe the d isp lay on the 5001- ; i f i t reads 9999.99,

1 0 0 0 0 . 0 0 r o F L 0 0 0 0 . 0 L , p r o c e e d t o s t e p l - 8 .1 - 7 . U s e t h e t u n i n g t o o l t o a d j u s t t h e t r i m m e r c a p a c i t o r f o r a

d i sp lay o f l - 0000 .00 .18 . Se lec t a ga te t ime o f L .0 seconds .l -9 . Observe the d isp lay on the 5001- ; i f i t reads 9999.999,

l - 0 0 0 0 . 0 0 0 , o r L 0 0 0 0 . 0 0 1 - , p r o c e e d t o s t e p 2 l - . .2 0 . U s e t h e t u n i n g t o o l t o a d j u s t t h e t r i r n m e r c a p a c i t o r f o r a

d i s p l a y o f 1 0 0 0 0 . 0 0 0 .2I . Select a gate t ime of l -0 seconds.22. I f the d isp lay on the 5001- reads 0000.0000 wi th the OVERFLOW

LED I i t , or f l ickers between th is reading and 0000.0001- wi ththe OVERFLOW LED I i t , or f l ickers between 0000.0000 wi th theOVERFLOW LED l i t and 9999.9999 with the OVERFLOW LED notl i t , proceed to s tep 24.

2 3 . U s e t h e t u n i n g t o o l t o a d j u s t t h e t r i m m e r c a p a c i t o r f o r ad isp lay of 0000.0000 wi th the oVERFLow LED 1i t .

2 4

24. Wait one hour; i f the display has not changed, cont lnue tostep 25. f f the display has changed, return to step 23.

2 5 . T u r n p o w e r o n t h e 5 0 0 1 - O F F . D i s c o n n e c t t h e p o w e r c o r d f r o mthe AC outlet. Disconnect the signal source from theA input. Fo1low the procedure under CASE REASSEMBLYcompletely.

This concludes the recal ibrat ion procedure.

l - .2 .3 .

5 .

6 ..7

8 .

9 .

CASE DISASSEIUBLY

Disconnect a l l input cables.Disconnect the power cord from the AC outtet.Turn the 5001- ups ide-down on a sof t or padded sur face.Remove the s t ick-on rubber feet f rom the foot assembl ies.Place then as ide, non-st icky s ide down.Remove the Phil l ips-head screw from each of the four footassemb l ies .Remove the foot assembl ies and the f l ip-up leg.Hold ing the top and bot tom case halves together , carefu l lyturn the case upr ight .Gent ly s l ide the top hal f o f the case st ra ight upward unt i li t i s c lea r o r t he un i t . The PC board w i l l now be v i s ib le .I f necessary, the PC board can be taken out o f the bot torncase hal"f by removing the self-tapping screw frorn the centerof the PC board, and l i f t ing the PC board, f ront paneI , andrear panel s t ra ight upward f rom the case as a uni t . Notethat the f ront panel , d isp lay board, and rear panel remainwired to the main PC board.

F igure 5 Case Disassembly/Reassembly

2 5

CASE REASSEIITBLY - see f igure 5

l - . Ensu re tha t no too l s rema in w i th in the case , and tha t , bo thupper and lower case halves are c lean and f ree of debr is .Remove a1l power and input connections.

2 . r f t h e u n i t h a s b e e n r e r n o v e d f r o m t h e r o w e r c a s e h a 1 f ,rep lace i t as fo l lows: A l ign the f ront panel over the swi tchassembry on the main pc board and, as a uni t , s l ide thefront and rear panels into the appropriate grooves (thef ront o f the case is the beveled s iAe) in the bot tom hal f o ft h e c a s e , w h i l e a l l o w i n g t h e r n a i n p c b o a r d t o d r o p i n t o t h ecase. Replace the se l f - tapping screw in to the center o f theboard, being sure that the holes in the four corners of theboard are a l igned over the holes in the corresponding bossesbefore t ightening th is screw.

3. Gent ly s l ide the top case hal f s t ra ight down in to pos i t iona t o p t h e b o t t o m c a s e h a I f , r n a k i n g s u r e t h a t t h e t o p a n db o t t o m b e v e l e d s i d e s f a c e t h e f r o n t a n d t h a t t h e f i o n t a n drear panels are f i t t ing proper ly in the case paner grooves.

4 - whi le hold ing the top and bot tom case harves Logether ,carefu l ly turn the uni t ups ide-down.

5. Posi t ion the f l ip-up leg and the foot assembl ies. The f l ip-up Ieg assenbly shourd be to the front, and the 1eg shouldfold rearward.

6. Replace the Phi l l ips-head screw in each foot assembly.Take care not to overt ighten.

7. Replace the s t ick-on rubber feet .8 . Return the 500L to the upr ight pos i t ion.

The 5001- is once again ready for use.

FT'NCTIONAL DESCRIPTION

The heart of the rnodel 5Ool- Universal Counter-Timer is afu1ly. integrated LSr universar counter/LED Display Driverc i rcu i t , the In ters i l Tcy l722G. Global specia l l ie-s has increasedt h e u t i l i t y o f t h i s e x t r e m e l y c a p a b l e I C w i t h t h e a d d i t i o n o f anumber of support circuits and features, ds well as handsomepackaging in a fu l l - featured profess ional inst rument .

The rcyI7226 has been designed to measure f requency, per iod,freguency ratio, and t ime intervals, and can also measure theaccumurat ion of events. wi th a 1o MHz crystar osc i r ra tor ,resorution in the nanosecond and fractionir Hertz range isachievable. Gat ing, reset , hoId, and storage s ignals areavai lab le to increase operat ional f lex ib i l i ty .

The 5oo1 provides identical input signal processing on bothinputs to fu1ly condit ion signals for optimum bperation of thelcyI7226. se lectable at tenuat ion, srope se lect ion, over loadprotect ion, t r igger 1eve1/DC of fset ad justment , and buf fer ing areincorporated in both channels. Both i iput prearnpli f iers aredesigned to handle s ignal f requencies up to 35 MHz; l i rn i ta t ionsof the rcr47226, however, restr ict operation to j-0 NIHz in the Achannel , 2 MHz in the B channel .

2 5

The mode, functj-on, and range controL switch matrix, inaddi t ion to fornat t ing the operat ion of the ICY|7226, prov ides forautomat ic c lear ing and reset t ing of the counters and the Disp layHold/Measurement Cycle Delay t irner whenever the sel-ected node orrange is changed. This a lso occurs when power is f i rs t turnedo n .

The Disp lay Hold/Measurement Cycleuser-var iab le delay in the ICt t I7226 Reset

Delay t i rner prov ides aoutput before i t reaches

t h e I C r s H o l d i n p u t .The Efght o .a: inch, seven-segment LEDs, a long wi th the

dj -screte Over f low and Gate LEDs, are dr iven by d iscretetransistors to perrnit higher drive currents, and therefore higherbr ightness.

Four separate vo l tage regulators are used in the 5OOL powersupply to assure opt imum iso lat ion between the d ig i ta l c i rcu i t ryand the analog s tages of input ampl i f icat ion.

A I N P U T

B I N P U T

Z Selects

F i g u r e O - B l o c k D i a g r a m

2 7

CIRCT'IT DESCRIPTION

Refer to the block diagran (figure 6) and the schernaticdiagran of the sooL dur ing tn is dis-cussion of c i rcui t operat ion.

fnput signals at the -a

and g inputs are connected directlyto-three posi t ion xr /xro/x j"oo at tenul tors (RLlc1 , R2/c42, nz1€+2,and s l -3 a t A ; R2 l ' / c ro , R2z /e44, R23/c45, and-s t -4 . a t B) .

' rnputprotect ion is provided by l -oo ohrn ser ies resistors (R7, R24) andd iodes D5-8 .

signals are then buffered and arnpl i f ied by high- impedanceJFET-input cornpound-series feedback ainpf if iers' (el-- and e2 for theA input, e3 and e4 for the B input) . i iasing ro ' i1n"=eanpl i f iers is adjusted by RLL and R30.

signals then reach high-speed cornparators u3 and ug, where! ! : v a r e c o m p a r e d t o l e v e l s s e t u y r r i g g e r L e v e l c o n t r o r s R 5 a n dR72, which are buffered by. op-ampu7 cont igured as vol tagefol-Iowers. Hysteresis is introduced into ihe conparators toassure c lean switching act ion even in the presencl of s low ornoisy input s ignals.

Exclusive-oR gates (U2) in conjunct ion wi th Slope switchessL1 and s12 determine whether r is ing or fa l r ing eagel wir l becounted.

N o t e t h a t t h e e n t i r e p r e a m p l i f i e r c i r c u i t f o r b o t hprearnpl i f iers is- degigned to work wi tn s ignal f requencies up to3 5 M H z i i n t e r n a l l i r n i t a t i o n s o f t h e L S r c o u n t e r r c , h o w e i e r ,l i m i t A c h a n n e r r e s p o n s e t o L 0 M H z a n d B c h a n n e l r e s p o n s e t o2 MHz.

Al l count ing, . gat ing, housekeeping, and dispray dr ive s ignaltasks are accomplished by u1_, an rnterl ir rcrrlT2;6. A detaileddescr ipt ion of i ts funct ion is beyond the scope of th is . . r , . ru i ,b u t a b r i e f s u r n m a t i o n o f i t s u s e i l i t h i n t h e 5 o o r r o r l o w s .

A measu lgrnen! in p rogress ou tpu t a t p in 2 tu rns on the Gateopen LED-]D2 o)--€h-rough -tr-f,ns-iFtor

a.-.- -

Function, range, and contror inputs are time-rnultiplexedonlo the digi t d isplay dr ive 1ines. serector pushbuttonswitchbank s2 through s1-0 routes appropriate ctde= io U1- throughc o n t a c t s i - n t h e i l A i l b a n k .

- Fgr Frequency, period, Frequency Ratio, and Tirne rnterval,the rrBrr bank of mode selectors sz through si; send a signal tot r a n s i s t o r e r - 7 a n y t i n e a n e w m o d e i s s e t e c t e d . T h i s i s o R e dYilh. a power-up reset signal generated by exclusive-oR gate U2 toinit iate a reset for uL ana oifay t iner u5. This same function

Here, the base of e17 is not groundLd directly through the i lB' 'sw i t chbank as i t i s i n t he o thL . r modes , bu t i s . i ns tead g roundedthrough the base-ern i t ter junct ion of qb; the ern i t ter o f ea isconnected to ground in every case except when the Resetpushbutton is selected in the Event co-unter mode. In this case,t h e e r n i t t e r i s d i s c o n n e c t e d a n d e 1 7 c a n t u r n o n t o a c c o m p l i s h areset sequence. When Hold is se lected, the base-emi t ter junct ionof Q7 is shor ted, .ar lowing e8 to turn on. This act ivates Delayt imer u5, which wi l t . keep-u l - f rom updat ing the d isp lay but wi l inot a f fect the count ing funct ion and wi l l not re=el the counters.s e l e c t i n g R u n w i l l r e l e a s e t h e s h o r t o n t h e b a s e o f e 7 , a l l o w i n g

2 8

i t to turn on, thereby turning off e8, releasing the Delay timer,and al}owing. u1 to update the display and continue counti-ng

.Delay t i rner U5 is a 555 t imer conf igured as a rnonostablenultivibrator. rt drives the Hold input of u1_, stopping anymeasurement in progress, resettlng the main counter-lnd-rnakingthe chip ready to init iate a new measurement. Arso, the naincounter data latches are not updated, so the display continues toshow the last cornplete measurement. However, betaule the inputto u5 is the Bgqe! ou tpu t o f u i - , u5 permi ts one comple temeasurement cycrJ (onry) before impbsing the Hold c-ondition. v2buffers the Reset s ignar f rom ut- . R45 ind c22 act as adi f ferent iator, and i lso alrow the oRing of the s ignals f rom thecol lector of Q8. Delay control R73, a logar i thmic potent iometer,varies the monostabre pulse width at the output of ts from75 ni l l iseconds to 7.s seconds; switch s15 extends i tindef in i te ly.

switch s15 also performs the r tpr imingtr funct ion necessaryfor the measurement of s ingle, non- iepet i t ive s ignals. when stsis- opened, as occurs when the De1ay c6ntrol is r5tated out of theHoId position, a narrow pulse is generated by the network made upo f D 2 6 , R L 4 , R 4 8 , . R 4 7 , c 2 3 , a n d c z L . T h i s p u t s e i s b u f f e r e d b yu6, which then dr ives hal f of u4, a 74),23 monostabremurtivibrator. one output of this harf is coupred, throughanother sect ion.of u6, to the A input of uL. ihe cornpren6ntaryoutput of the f i rst harf of u4 is used to t r igger the secondharf ; . an output of the second harf is coupredj-again through as e c t i o n o f u 6 , t o t h e B i n p u t o f u 5 . T h e e n d r e i u l t o f t h l s i sto provide an A-to-B transi t ion, which readies uL for a s inglemeasurement.

Transistors eL8 through e25 buffer both digit and segmentdisplay dr ive I ines, permit t ing higher dr iv ing 6,rrr . t t= foropl lTul d isplay br ightness. rhe overf low LEi (Dl j - ) isnul t ip lexed in place of the most s igni f icant digi t ls decimalpo in t .

The power supply makes l iberar use of three-terrninalregulators. Note that there are separate regulators for theanalog and digi ta l sect ions of the instrumenl; th is helps toensure maximum isolat ion between the stages. Regulators A4 andA3 provide * l -0 vorts and -J-0 voI ts, respect iveryj which are usedgnly - for .comparators u3 and u8. Regulator Al_ s i r i :p l ies +5 vol tsfor the input preampl i f icat ion sect ions. negulal l r A2 generatesthe +5 vol t supply used in al l of the rernaining digi ta lc i rcui t ry.A input of the soot-. proceed as detaired under the operatingInstruct ions sect ion.

2 9

APPLICATIONS

Frequency Counter

Always measure osc i l la tor f requencies af ter a t least onestage of buffering; measurements taken at the osci l latorcomponents thernselves can pull the osci l lator off-frequency.When th is is unavoidable, us ing a Xi -O osc i l loscope probeconnected to the A input o f the 500L wi1 l n in i rn ize c i rcu i tloading, reducing this frequency shift . Keep in nind, however,t h a t a X L O p r o b e w i l l r e d u c e t h e s i g n a l a n p l i t u d e t o t h e i n p u t o fthe 500L by a factor of 10, thus reducing the apparentsensi t iv i ty ; s ignals of less than 200 rn i l l ivo l ts RMS anpl i tudernay not be measurable. In addit ion, the Trigger Level controlwil l behave as though the attenuator was switched into the nexthigher range of attenuation.

Cer ta in cr i t ica l appl icat ions nay requi re that the 500Linput impedance be identical to circuit impedance,' for example, a50, 75, or 300 ohm terminat ion may be requi red to proper ly loadthe circuit under test. Since both the A and B inputs are highimpedance, th is terminat ion may be appl ied at the 5OOi- inputd i rec t l y .

When measur ing t ransmi t ter and other rad iated f ie ldf requencies, a shor t p iece of wi re or te lescopic antennaconnected directly to the 5OOl- input may provide adequatecoupling for a rel iable reading. DO NOT ATTEI{PT TO CONNECT THE5OO]. INPI]:T IN PI,ACE OF THE TRA}TSI{ITTER ANTENNA OR N.IYWHEREDIRXCTLY TN THE TRJANSITIISSION LINE.

T o m e a s u r e a f r e q u e n c y t h a t i s o n l y a v a i l a b l e f o r a s h o r tt ime, set the Delay contro l to i ts Hold (detent , fu l lycounterclockwise) posit ion, press in the Frequency pushbutton ands e l e c t a g a t e t i n e o f . L , 1 - , o r 1 0 ( b u t n o t . 0 L ) s e c o n d s .Disregard the d isp lay at th is po int . As soon as the s ignal isavai lab le, press in the .01 second gate t ime pushbut ton. Thesignal then only need remain va l id for 10 n i l l iseconds; theinstrument wil l complete one measurement cycle in that t ime andwi l l d isp lay the resul ts of that measurernent unt i l the gate t imeis changed, the mode is changed, or the Delay control is takenout of the Hold posi t ion.

For fast , accurate measurements of 1ow f requencies, use thePeriod mode and calculate the frequency as the reciprocal ofp e r i o d , i . e . ,

f requency ( in t ' tHz1 : L /per iod ( in n icroseconds)

See the Per iod Measurement sect ion, be low, for a fur therd iscuss ion of the Per iod funct ion.

Freqtrency Counter example - measuring nicroprocessor clockf requency: Locate the microprocessorrs buf fered c lock output .Assuming the signal is at, TTL 1eve1s, set the A input Attenuatorto X10, set the Tr igger Level contro l to 1.5 voLts (approx inate lythe L:30 posi t ion) , and connect c lock and ground d i rect ly to the

3 0

Period lleasurement

The accuracy of this measurement is very dependent upon theamount of noise present on the input signal; display instabil i tyn a y b e o b s e r v e d e v e n w h e n t h i s n o i s e i s b e l o w t h e 5 0 0 1 - r s n o i s ethreshold. To substantial ly reduce this effect, take the averageover a larger number of cycles, increase the input anpli tude ofthe waveform, and/or select the steeper edge of the waveform asthe tr iggering edge.

Period measurements yield much quicker and more accurateresults than freguency measurements for 1ow frequency phenomena.For example, i t would take l -0 seconds to prov ide 0.L H2resolution in deternining the frequency of a l- l-0.4 Hz(0.1L04 RHz) s ignal in the Frequency Counter mode; in the Per iodmode, a L00 cyc le average of gO5T.gTL rn icroseconds is avai lab lein less than one second. ff the period were instead to bemeasured as 9057.946 microseconds, the f reguency could becalcu lated as LL0.4003 Hz, y ie ld ing an addi t ional three accurated i g i t s .

PHOTOVOLTAIC CELLFOR CADMIUM SULPHIDE CELL ORPHOTOTRANSISTOR, VISE CIRCUIT SHOWN IN FIGURE 9.

Figure 7 - Period Application

Period Measurement exanple - measuring the speed of a notionpic ture (nov ie) pro jector : L ike many phenornena, the speed of amot ion p ic ture pro jector rnay be measured ind i rect ly us ing the5001- more s i rnp ly , more convenient ly , and more accurate ly thanthrough d i rect measurements of mechanica l mot ion. In the case ofa mot ion p ic ture pro jector , the var iab le of in terest is f ramerate in f rames per second. Nominal ly , most pro jectors run ate i ther 1-6 or 24 f rames per second; in te lev is ion f i ln chains,every f i f th f rarne is pro jected twice, conver t ing nominal 24 f rameper second rnotion pictures to standard 30 frame per second videorates. Accurate frarning of video picture information within syncrequi res that pro jector speeds be especia l ly accurate. The 5OO1permits accurate measurement of these low freguencies throughrec iprocal ca lcu lat ion of per iod, as measured by leading edges ofphotosensit ive transducer outputs in response to each projectedframe. (see f igure 7) A photovol ta ic ce l l may be connected d i -rec t l y t o t he 5001 inpu t , bu t response o f t hese i s usua l l y s lowerthan that o f o ther photodetectors. A photodiode or photot rans is torcan be used, but some s ignal condi t ion ing wi l l be necessary; anexample of an appropr ia te s ignal condi t ion ing c i rcu i t is shown inf i gu re 9 .

3t_

w i t h n o f i l m i n t h e p r o j e c t o r , a n d b o t h m o t o r a n d r i g h t t u r n e dotr , prace the sensor direct ly in f ront of the lens. The framer a t e c a n n o w b e c a l c u l a t e d b y t a k i n g t h e r e c i p r o c a l o f t h edisplayed per iod. some degree of opt ical f i l ler ing, l i rn i t ing, ofshadowing nay be necessaryl dependfng on the specii ics of thedetector being used.Time Interrral

Unlike other measurernent modes that uti l ize nultiple cycleaveraging, multiple Time Interval averaqed measurenentiaccumulate the total errors occurring i; each cycle; this irnpliesboth that some j i t ter is inevi tabre when averaging mult ip leintervals increasing with the averaged nurnber o-t intervals -and that variance between single interval measurements is to beexpected.

The Time fnterval mode provides a highly useful faci l i ty fordeterrnil ing pulse parameters. This is done by externarlycom_m.on ing the A and B inputs so tha t the input s ignar w i l l beapplied to both inputs sinultaneously. pulse wiatn (the "hjgryrt i n e ) c a n t h e n b e d e t e r r n i n e d b y s e l e c t i n g t h e r i s i n g e d g e o n l h eA input slope selector and the fall ing edge on the a input slopeselector. Pulse spacing ( the t lowrr t ime) can be determined by-select ing the fal l ing edge on the A input Slope selector and Lher is ing.edge on the B input s lope sereclor. putse per iod can bedetermined by taking the surn of the pulse width and pursespacing, or by serect ing the per iod rnode of the 5ooL: pulserepetit ion rate can be determined by taking the reciprocal of thepurse period, or by serecting the Frequency counter lnode of the?091. .Duty cycle can be deternined mathenat ical ly. Thefol lowing formulae apply:

p e r i o d = W i d t h + S p a c i n g

Duty Cyc1e = (Width/Spacing) X l_oO= (width/ (width + Spacing) ) X t_00: Width X Frequency X LOO

Repetition Rate : ilH:rFrequency: 1 / (Width + Spacing)

l l _ -

t* t O

'Condit ioning Circuit, see Figure 9.To

ISTOP

Time fntenral exampletime of falt for ball istico f f l i g h t a n d t i r n e o f f a l I

- measuring the tine of flight andprojecti les or fal l ing objects: Timem a y b e d i r e c t l y m e a s u r e d b y t h e 5 0 O l - .

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Figure 8 - Time Interval Application

The Disp lay Hold feature is especia l ly usefu l in th is casebecause it always perrnits one and only one measurement cycle,which cannot begin unti l the appearance of the selected eage atthe A input in the Tine Interval mode; once the measuremeni cyclei s compre ted w i th the appearance o f t he se rec ted edge a t t he Binput , the d isp lay is he ld indef in i te ly . Arranging b lect r ica lcontacts directly in the path of the object is the sirnplest meansof prov id ing appropr ia te input s ignals to the sOOL, and isacceptable i f the force associated wi th the mass and ve loc i ty ofthe object is large compared to the contact breaking (or rnaking)force reguired. Note that by using contact opening as thesignif icant event, errors due to contact bounce problems areavoided. Alternatively, photoelectr ic beam-break detectors maybe used, or other methods more convenient to the specif ic test.once clean input signals are available, the measurement can betaken 10, L00, or l -000 t imes us ing mul t ip le cyc le averaging;beware, however, of contact bounce when switches are restored totheir resting posit ion between measurernents.

Freguency Ratio

I n m a n y c a s e s , t h e 5 0 0 1 - w i l l b e u s e d i n c o n j u n c t i o n w i t h asignal derived from the metering of a physicar phenomenon, suchas rotat ionar speed, f low, l inear speed, or weight . The sooL canbe configured to display measurements in terrns of the actuaruni ts of in terest ( for example, RpM, gal rons per minute, fur longsper for tn ight ) by tak ing advantage of the scal ing (a lso car ledrescal ing) capabi l i t ies of the 5OO1- in the f requency Rat io rnode.rn this mode, the instrurnent indicates how nany signal edgesappear a t t he A i npu t du r ing the se lec ted number o f edges a t t heB. input . rn other words, the B input s ignal r rgates, , the A inputsignal. Therefore, instead of displaying frequ-ency measurementsin cycres per second (Her tz) , they are in cyctes pLr B s ignalpe r iod .

The f requency to app ly to the B i npu t can be de te r rn ined asfo l l ows :

1-. Deterrnine how many pulses occur per event of interest andconvert into the units urt imately desired for the 5ooi-d isp lay. For example, i f the number of pu lses der iveredper p in t a re known , mu l t i p l y by l _6 to conve r t t o pu l sesper ga l l on .

2. Express L second in terms of the t ime uni ts des i red. Forexa rnp le , l / 60 m inu te , l _OO0 rn i l l i seconds , I / 3600 hou r .

3. carculate the frequency needed at the B input as forlows:

Frequency at ! = (pulses per event) X (t ime units inseconds)

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4. Using a f requency source, such as the GlobaL Special t iesmodel 4001- Pulse Generator or the nodel 2OO2 Funct ionGenerator, provide the appropriate signal frequency tothe B input. Note that the B input cannot accept afrequency greater than 2 MHz.

, Frequency Ratio exampre - motor Rpll dispray: rf an encodingd isk on a motor shaf t g ives Lo24 pu lses per rLvo lu t ion and themotor is rotat ing at one revolut ion per second, the 5o0L wi l rdisplay a L,o24 krtz reading in the Fieguency mode. To convertthis to RPM using the Freguency Ratio frode,- divide the encodingdisk output f requency by 60 (L.02 4 k] f .z/6o = o.o17o7 kHz :)-7.o7 Hz). Using this f reguency as the B input and select ing theF r e q u e n c y R a t i o m o d e w i r l y i e t d a d i s p l a y o f R p M , i n t h i s c a J e60. Note that the B input frequency must be from a separates o u r c e f r o m t h e A i n p u t , a n d n o t s i r n p l y a d i v i d e d r e s u l t o f t h e AJ-nput, or erse a change in the a input treguency wil l cause achange in the B input frequency, and the rit io (and therefore thedisplay) wi l l remain unchanged.

Event Counter

As in other modes of operat ion, the f lexibi l i ty of the 5OOl-input circuitry permits a great many devices to be

-used as

sensors, requir ing only very s impre interface circui t ry ( theinputs respond onry to vort lges, so s imple contact c losures andimpedance changes require some conditioiring with externalc i rcu i t ry ) (see f igure 9) .

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Fig"ure 9 - Signal Conditioning Circuit

Addit ional condit ioning of input signars may be required toget accurate counts i f the signals include gritches, contactbounce, or a great dear of noise. The circuitry needed may be assimple as an RC fi l ter at the soot- inputs, or a! involved as amonostable rnult ivibrator tr iggered by the signali the amount ofcondi t ion ing necessary wi l l depend on tne ch l racter is t ics of the

,) \ContactPhototransistorY

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signar. The circui t of f iqure 9 is presented as one example ofs ignal condi t ioning scherne. rn the tase of purely electronicsignals, such as error signals generated frorn a microprocessor,no signal condi t ioning should be required at a l l .

PHOTOTRANSISTOR

Circuit, see Figure 9.

Figure 1-O - Event Counter Application

Event counter exampre - counting items on a conveyor bert:A s imple photoelect r ic beam break arrangement prov ides a su i tab leinpu t f o r t he 5001 . ( see f i gu re 10 ) . Assuming each i t em on theconveyor breaks the beam once and only once, the 5001 can keep arunning count on product . ion.

External Timebase

By us ing the external t imebase capabi r i t ies, a var ie ty ofusefu l e f fects can be real ized. The most obv ious enhancementthat is poss ibre is increased accuracy in the Frequency, per iod,and Time Interva l modes ( the External T imebase hai no bf fect inthe Freguency Ratio or Event Counter modes). Other uses includethe abil i ty to extend period and t ime interval measurements up tol -000 seconds or to scale the reading to be uni ts other thanseconds, and to perform ratio-type measurements at frequenciesabove that possible in the Frequency Ratio mode. Note that thesignal applied to the Externar Timebase input must be at rr l ,Ievels . r f no s ignal is present at the input , Do Nor swi tch in tothe External Tirnebase mode - damage to the display could result.

External Timebase exanples - extended period measurement:when us ing the 50ot- wi th the in ternal t i rneb-se, per iodmeasurements of f requencies l -ess than o.1 Hz cause counter

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overf low, result ing in uncertainty as to the f inal result.Consider the case where a 0.0L667 Hz s iqnal is to be measured.Using the in ternal t imebase, a d isp lay ; f 9989002.4 microsecondswith the Overf low LED l i t would result. I f a l- MHz externalt imebase is used instead, the most s ign i f icant d ig i t would not beIost , g iv ing a reading of 5998800.2 wi th no Over f low ind icat ion.Note that the decimal point does not now show the microsecondposit ion; the interpretation of the display must be made bearingin nind the difference between the internal and external t imebasefreguencies. In this example, the external t imebase frequency isI / L 0 t h a t o f t h e i n t e r n a l t i r n e b a s e , s o t h e r e a d i n g n u s t b emu l t i p l i ed by 10 , y ie ld ing a pe r iod o f 59988002 m ic roseconds , o r5 9 . 9 8 8 0 0 2 s e c o n d s .

Scal ing example: Consider the t i rne in terva l exarnple off igure 8; i f the contacts were p laced one rneter apar t , the 5OOl-would d isp lay the e lapsed t ime for an object t ravel ing one meter .I f i t was desi red instead to measure the t ime requi red to t ravelo n e f o o t , o n e w a y t o a c c o m p l i s h t h i s w o u l - d b e t o s u p p l y a nappropr ia te external t imebase. As one foot = 0.3048 meters, theuse o f an ex te rna l t i r nebase o f 3 .048 l {Hz (0 .3048 X LO MHz) wou ldresul t in the d i rect d isp lay in the desi red uni ts wi thout movingthe contacts or resor t ing to ca lcu lat ions for each measurement .

High-frequency ratio example: fn the Frequency Ratio mode,frequencies above 2 l{Hz cannot be used at the B input. This isnot norrnal ly a ser ious l in i ta t ion, but there could be occasionswhere h igher f requency capabi l i t ies would be usefu l . TheExternal Timebase feature can be used to irnplenent this function.As an example, to compare two osc iL la tors running at a norn inal3.579545 NIHz, use one of the osc i l la tors as the external t imebaseand feed the other osci l lator into the A input. selecting theFreguency Counter mode with a gate t ine of .01- seconds, a readingof L0000.0 would ind icate an exact rnatch. A d isp lay of 9999.9would ind icate that the s ignal present at the A input is o .oo2eolower than the external t imebase frequency.

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SERVICE AND WARRANTY INFORMATION

FACTORY SERVICE AND REPAIRGlobal Specialties will service and repair this instrument free of charge for a period of one full year, sub-ject to the warranty conditions below.

To obtain a return merchandise authorization (RMA) required for all returns, phone our Customer Ser-vice Department for an RMA and all shipping instructions: Tel. go0-572-102gor wrile:

GLOBAL SPECIALTIES1486 Highland Avenue, Unit 2Cheshire, CT 06410(2AQ272-3285Tel.(203)2724330 FN<

WARRANTYGlobal Specialties warrants this device to be free from defective material or workmanship for a period of

one full year from date of original purchase.

Global Specialties under this warranty is limited to repairing the defective device when returned to thefactory, shipping charges prepaid, within one full year from date of original purchase.

Units returned to Global Specialties that have been subject to abuse, misuse, damage or accidenl, orhave been connected, installed or adjusted contrary to the instructions furnished by Global Specialties, orthat have been repaired by unauthorized persons will not be covered by this warranty.

Global Specialties reserves the right to discontinue models, change specif ications, price or design of thisdevice at any time without notice and without incurring any obligation whatsoever.

The purchaser agrees to assume all liabilities for any damages and/or bodily injury which may resultfrom the use or misuse of this device by the purchaser, his employees, or agents.

This warranty is in lieu of all other representations or warranties expressed or implied and no agent orrepresentative of Global Specialties is authorized to assume any other obligation in connection with thesale and purchase of this device.

BREADBOARDING SOCKETS LIFETIME GUARANTEEAll Global breadboarding sockets are guaranleed for life. lf a socket ever fails to meet your requiremenls,

return it and we will replace it, NO QUESTTONS ASKED.

Specifications subject to change without notice.O Copyright 1985, TNTERPLEX ELECTBONTCS, tNC., New Haven, Cf

@ and TM trademarks are the property ot INTERPLEX ELECTRONICS, lNC., New Hav€n, CT.. t9B5

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