Type 846 Electro-Pneumatic Valve Positionerlinearcontrols.net/intranet2/Fisher/Fisher/Manuals/D012077.pdftested per SAMA Standard PMC 33.1C–1978, change in steady–state deviation

D10

2077

X01

2

�Fisher Controls International, Inc. 1994, 1995; All Rights Reserved

Fisher, Fisher-Rosemount, and Managing The Process Better are marks owned by FisherControls International, Inc. or Fisher-Rosemount Systems, Inc.HART is a mark owned by Rosemount Inc.All other marks are the property of their respective owners.

This product may be covered by one or more of the following patents (4,481,967; 4,534,376;4,638,830; 4,653,523; 4,665,938; 4,760,859; 4,777,826; 4,901,756) or under pending patentapplications.

Fisher-Rosemount satisfies all obligations coming from legislation to harmonise product requirements in the European Union.

Type 846 Electro-Pneumatic TransducerContents

1. IntroductionScope of Manual 1–1. . . . . . . . . . . . . . . . . . . . . . . . . . Description 1–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Specifications 1–2. . . . . . . . . . . . . . . . . . . . . . . . . . . .

2. InstallationMounting 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pressure Connections 2–1. . . . . . . . . . . . . . . . . . . . .

Supply Pressure 2–1. . . . . . . . . . . . . . . . . . . . . . . . . Output Pressure 2–3. . . . . . . . . . . . . . . . . . . . . . . . .

Electrical Connections 2–5. . . . . . . . . . . . . . . . . . . . . Stroke Port 2–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Exhaust Port 2–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Signal Interruption 2–6. . . . . . . . . . . . . . . . . . . . . . . . .

3. CalibrationStandard Performance:

Full Range Input, Direct Action 3–1. . . . . . . . . . . Multirange Performance:

Full Range Input, Direct Action 3–2. . . . . . . . . . . Standard Performance:

Split Range Input, Direct Action 3–2. . . . . . . . . . . 4 to 12 mA Input Signal 3–2. . . . . . . . . . . . . . . . . . . 12 to 20 mA Input Signal 3–2. . . . . . . . . . . . . . . . . .

Standard Performance:Full Range Input, Reverse Action 3–3. . . . . . . . .

Multirange Performance:Full Range Input, Reverse Action 3–3. . . . . . . . .

Standard Performance:Split Range Input, Reverse Action 3–3. . . . . . . .

4 to 12 mA Input Signal 3–3. . . . . . . . . . . . . . . . . . . 12 to 20 mA Input Signal 3–3. . . . . . . . . . . . . . . . . .

Transporting the Module Final Assembly 3–4. . . . .

4. Principle of OperationElectronic Circuit 4–1. . . . . . . . . . . . . . . . . . . . . . . . . . Magnetic Actuator 4–1. . . . . . . . . . . . . . . . . . . . . . . . . Pilot Stage 4–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Booster Stage 4–2. . . . . . . . . . . . . . . . . . . . . . . . . . . .

5. TroubleshootingDiagnostic Features 5–1. . . . . . . . . . . . . . . . . . . . . . .

Stroke Port 5–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Remote Pressure Reading (RPR) 5–1. . . . . . . . . .

Using the HART Communicator toRead the RPR Signal 5–1. . . . . . . . . . . . . . . . .

Using a Frequency Counter toRead the RPR Signal 5–1. . . . . . . . . . . . . . . . .

In-service Troubleshooting 5–2. . . . . . . . . . . . . . . . . Troubleshooting in the Shop 5–4. . . . . . . . . . . . . . . .

6. MaintenanceModule Final Assembly 6–1. . . . . . . . . . . . . . . . . . . .

Removing the Module Final Assembly 6–1. . . . . . Replacing the Module Final Assembly 6–3. . . . . .

Electronic Circuit Board 6–4. . . . . . . . . . . . . . . . . . . . Optional Remote Pressure Reading (RPR)

Jumper 6–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Range Jumper 6–5. . . . . . . . . . . . . . . . . . . . . . . . . . Action 6–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Removing the Electronic Circuit Board 6–5. . . . . . Replacing the Electronic Circuit Board 6–5. . . . . .

Pilot/Actuator Assembly 6–6. . . . . . . . . . . . . . . . . . . . Action 6–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Removing the Pilot/Actuator Assembly 6–6. . . . . . Replacing the Pilot/Actuator Assembly 6–6. . . . . .

Module Subassembly 6–7. . . . . . . . . . . . . . . . . . . . . . Terminal Compartment 6–7. . . . . . . . . . . . . . . . . . . . . Exhaust and Stroke Port Screens 6–7. . . . . . . . . . .

7. Parts List

8. Loop Schematics

Section 1Introduction

Scope of ManualThis instruction manual provides installation, operat-ing, calibration, maintenance, and parts ordering in-formation for the Type 846 electro-pneumatic trans-ducer. Refer to separate manuals for instructionscovering equipment used with the transducer.

Instruction ManualForm 5354

November 1995Type 846

Type 846

1–2

Figure 1-1. Type 846 Electro-Pneumatic Transducer Mountedon a Type 667 Actuator

W6307–1/IL

Only personnel qualified through training or experienceshould install, operate, or maintain the transducer. Ifthere are any questions concerning the instructions inthis manual, contact your Fisher sales office or salesrepresentative before proceeding.

DescriptionThe Type 846 electro-pneumatic transducer, shown infigure 1-1, accepts an electrical input signal and pro-duces a proportional pneumatic output. Typically, 4 to20 mA is converted to 3 to 15 psi (0.2 to 1.0 bar).Models are available in direct or reverse action andfield-selectable full or split range inputs. See Section 3Calibration for more information on input/output com-binations.

The most common application of the Type 846 is toreceive an electrical signal from a controller and pro-duce a pneumatic output for operating a control valveactuator or positioner. The Type 846 may also be usedto transduce a signal for a pneumatic receiving instru-ment.

The Type 846 is an electronic I/P transducer. It has asingle electronic circuit board, as shown in Figure 1-2.

Figure 1-2. Type 846 Modular Construction

A6643/IL

MODULE COVER

MODULE FINALASSEMBLY

ELECTRONICCIRCUIT BOARD

MODULE HOUSING

TERMINAL BLOCK

TERMINALCOMPARTMENTCOVER

The circuit contains a solid-state pressure sensor thatmonitors output pressure and is part of an electronicfeedback network. The self-correcting ability providedby the sensor/circuit combination allows the Type 846to produce a very stable and responsive output signal.

All active mechanical and electrical components of theType 846 are incorporated into a single, field-replace-able module called the module final assembly, shownin Figure 1-2. The module final assembly contains theelectronic circuit board, pilot/actuator assembly, andbooster stage. The module final assembly is easilyremoved by unscrewing the module cover. Its designminimizes parts and reduces the time required for re-pair and troubleshooting.

The terminal compartment and module compartmentare separated by a sealed compartment wall. Thismulti-compartment housing also protects the electron-ics from contaminants and moisture in the supply air.

SpecificationsSpecifications for the Type 846 transducer are listed intable 1-1.

Type 846

1–3

Table 1-1. Specifications

Input Signal (1)

� 4 to 20 mA dc, � 4 to 12 mA dc, or � 12 to 20mA dc. Field adjustable split ranging

Output Signal (1)

Standard Performance: � 3 to 15 psig (0.2 to 1.0bar). Rangeability between 1 and 18 psi (0.1 to 1.2bar).Multirange Performance: � 0.5 to 18 psig (0,03 to1.2 bar), � 6 to 30 psig (0.4 to 2.0 bar), and � 0.5to 33 psig (0.03 to 2.3 bar). Rangeability between0.5 and 33 psi (0.03 to 2.3 bar).Action: � Direct (increasing input signal increasestransducer output) (Minimum span, 6 psi) or � Re-verse (increasing input signal decreases transduceroutput) (Minimum span, 11 psi)

Supply Pressure (1)

Standard Performance18 to 24 psig ( 1.2 to 1.6 bar)Multirange PerformanceMinimum: 3 psig(4) (0.2 bar) greater than the maxi-mum calibrated output pressureMaximum: 35 psig (2.4 bar)

Steady-State Air Consumption (2)

0.20 scfm (0.3 normal m3/hr) at 20 psig (1.4 bar)supply pressure

Output Air Capacity (2)

Standard Performance: 4.0 scfm (6.7 normalm3/hr) at 20 psig (1.4 bar) supply pressureMultirange Performance: 6.0 scfm (9.0 normalm3/hr) at 35 psig (2.5 bar) supply pressure

Temperature Limits

Operating: (1) –40 to 185°F (–40 to 85°C).Storage: (1) –40 to 200°F (–40 to 93°C).

Humidity Limits

0 to 100% condensing relative humidity.

Performance (3)

Linearity (1), Hysteresis (1), and Repeatablility:�0.3% of span. Reference SAMA PMC 31.1.Temperature Effect (total effect including zeroand span): �0.045%/°F (0.07%/°C) of spanVibration Effect: �0.3% of span per g during thefollowing conditions:

5 to 15 Hz at 4 mm constant displacement15 to 150 Hz at 2 g. 150 to 2000 Hz at 1 g.

per SAMA Standard PMC 31.1-1980, Sec. 5.3,Condition 3, Steady StateShock Effect: �0.5% of span, when tested perSAMA Standard PMC 31.1, Sec. 5.4.Supply Pressure Effect: NegligibleElectromagnetic Interference (EMI): (1) Whentested per SAMA Standard PMC 33.1C–1978,change in steady–state deviation is less than�0.1% of span at 30 V/m, Class 3 (wire in conduit),ABC.�1.0% of span at 10 V/m, Class 2 (wire not in con-duit), ABC.Leak Sensitivity: (2) Less than 1.0% of span for upto 3.0 scfm (5.0 normal m3/hr) downstream leak-age.Overpressure Effect: Less than 0.25% of span formisapplication of up to 100 psi (7.0 bar) supplypressure for less than 5 minutes to the input port.

Reverse Polarity Protection: No damage occursfrom reversal of normal supply current (4 to 20 mA)or from misapplication of up to 100 mA.

Connections

Supply and Output Pressure: 1/4–18 NPT femaleconnection.Electrical: 1/2–14 NPT female conduit connection

Adjustments

Zero and Span: screwdriver adjustments located interminal compartment.

Remote Pressure Reading (optional)

Jumper selectable, ON or OFF, if unit includes op-tionFrequency Range: 5,000 to 8,000 Hz.Amplitude: 0.4 to 1.0 Vp-p

Required Operating Voltage

with Remote pressure Reading OffMin. 6.0 V (at 4 mA)Max. 7.2 V (at 20 mA)

with Remote Pressure Reading OnMin 6.4 V (at 4 mA)Max. 8.2 V (at 20 mA)

Weight

6.5 lb (2.9 kg) excluding options

Hazardous Locations Certifications

Refer to the Hazardous Area Classification Bulletin9.2:001 and the transducer nameplate (see figure1-3).

–Continued–

Type 846

1–4

Table 1-1. Specifications (continued)

Housing ClassificationCSA Type 4X, NEMA 4X, designed to meet IP66,tropicalization (Fungus test per MIL-STD-810)

Options� Type 67AFR filter regulator, � supply and output

gauges or � tire valves, � remote pressure read-ing, � module cover with multiple stroke ports,� stainless steel housing, or � stainless steelmounting bracket

1. This term is defined in ISA Standard S51.1-1979.2. Scfm—Standard cubic feet per minute (60�F and 14.7 psia). Normal m3/hr—Normal cu-bic meters per hour (0�C and 1.01325 bar, absolute).

3. Performance values are obtained using a transducer with a 4.0 to 20 mA dc input signal,a 3 to 15 psig (0.2 to 1.0 bar) output, and a 20 psig (1.4 bar) supply pressure.4. 2 psig (0.14 bar) for a 33 psig (2.3 bar) output

Figure 1-3. Typical Nameplate

INFORMATION IN THIS AREAIDENTIFIES THE HAZARDOUS AREACLASSIFICATION AND APPROVALSFOR THE PRODUCT SPECIFIED ONTHE EQUIPMENT ORDER

B2464

Type 846

2–1

Section 2 InstallationWhen a control valve is ordered with a Type 846 trans-ducer specified to be mounted on the actuator, thefactory-mounted transducer is connected to the actua-tor with the necessary tubing and calibrated to thespecifications on the order.

If the transducer is purchased separately for mountingon a control valve already in service, all the necessarymounting parts are furnished, if ordered. This includesthe appropriate bracket for attaching the unit to an ac-tuator boss (with tapped holes) or for attaching it to thediaphragm casing.

If preferred, mounting parts can be supplied for mount-ing the transducer on a 2-inch (51 mm) diameter pi-pestand, a flat surface, or a bulkhead.

MountingFigures 2-1, 2-2, and 2-NO TAG show the mountingdimensions. Mount the unit with the stroke port down.This allows any moisture buildup in the terminalcompartment to drain to the signal wire conduit en-trance. Any moisture in the pilot stage area will be ex-pelled through the stroke port without affecting pilotstage operation. As an alternative, the Type 846 maybe mounted horizontally. However, it must be mountedso that the flat bracket-mounting surface is down. Inapplications with excessive moisture in the supply air,vertical mounting allows the most effective drainagethrough the stroke port.

Before mounting the Type 846, note the following rec-ommendations:

� Ensure that all bolts are fully tightened. The recom-mended torque is 16 lbf�ft (22 N�m).

� Bolts that connect to the Type 846 and to a valveactuator should have the lock washer placed directly be-neath the bolt head and the flat washer placed betweenthe lock washer and bracket. All other bolts should havethe lock washer next to the nut, and the flat washerplaced between the lock washer and bracket.

� Do not mount the Type 846 in a location where for-eign material may cover the stroke port or exhaust port.See the descriptions of the stroke port and exhaust portlater in this section.

Pressure ConnectionsAs shown in figure 2-1, all pressure connections are1/4-18 NPT female connections. Use 3/8-inch (9.5mm) outside diameter tubing for the supply and outputconnections.

Supply Pressure

WARNING

Personal injury or property damage mayoccur from an uncontrolled process ifthe supply medium is not clean, dry, oil-free, or non-corrosive gas. Industryinstrument air quality standards de-scribe acceptable dirt, oil, and moisturecontent. Due to the variability in natureof the problems these influences canhave on pneumatic equipment, FisherControls has no technical basis to rec-ommend the level of filtration equipmentrequired to prevent performance degra-dation of pneumatic equipment. A filteror filter regulator capable of removingparticles 40 microns in diameter shouldsuffice for most applications. Use ofsuitable filtration equipment and the es-tablishment of a maintenance cycle tomonitor its operations is recommended.

WARNING

Explosions may cause death or seriousinjury. Do not operate the Type 846 withthe CENELEC flameproof options at asupply pressure in excess of 20 psi (1.4bar). Doing so invalidates the CENELECflameproof certifications and could al-low flames to spread from the unit po-tentially igniting and causing an explo-sion.

The supply medium must be clean, dry air or noncor-rosive gas that meets the requirements of ISA Stan-dard S7.3-1975 (R1981). An output span of 3 to 15psig (0.2 to 1.0 bar) requires a nominal supply pres-sure of 20 psig (1.4 bar) and a flow capacity not lessthan 4 SCFM (0.11 m3/min). For multirange perfor-mance units with higher output spans, the supply pres-sure should be at least 3 psig (0.2 bar) greater thanthe maximum calibrated output pressure, but shouldnot exceed 35 psig (2.4 bar).

The air supply line can be connected to the 1/4–18NPT supply port, or to the supply port of a filter-regula-tor mounted directly to the transducer.

The mounting boss for the air supply connection con-tains two 5/16–18 UNC tapped holes that are 2-1/4inches apart. The tapped holes allow direct connectionof a filter-regulator having a matching through-bolt pat-tern. A filter-regulator with mounting hardware is avail-able. The mounting hardware consists of two 5/16–18x 3-1/2 inch grade 5 bolts and one O-ring. See Table6-1 for the O-ring size. The O-ring is positioned in the

Type 846

2–2

Figure 2-1. Type 846 Dimensions and Connection Locations

4.64(118)

4.62(117)

STROKE PORT

OUTPUT GAUGE PORT1/4-18 NPT

NAMEPLATE EXHAUST PORTUNDERNEATH NAMEPLATE

CONDUIT CONNECTION1/2 - 14 NPT

OUTPUT PORT1/4 - 18 NPT

��

� ��

WIRING CONNECTION

1.38(35)

1.16(29)

1.13(29)

2.31(59)

COVERREMOVAL

4.33(110)

4.00(102)

5/16-18 (2)

O-RING GROOVEFOR FILTERREGULATOR

SUPPLY PORT1/4-18 NPTPOSITIVE

NEGATIVE

GROUND

NOTE;DIMENSIONS ARE IN INCHES (MILLIMETERS).

B2473/IL

TEST PINS

Type 846

2–3

FOR PROPER MOISTUREDRAINAGE THIS ENDMUST BE UP

Figure 2-2. Typical Type 846 Dimensions with Type 67AFR Filter/Regulator and Gauges

2.6266.5

COVER REMOVALCLEARANCE

8.81223.8

2.7569.9

3.0677.7

5.38136.7

2.2557.1

2.0050.8

.348.6

MODULE COVERREMOVAL CLEARANCE

6.38162.1

.256.4

8.44214.4 MAX

YOKE MOUNTED

NOTE: THE MOUNTING POSITIONS SHOWN ALLOW ANY MOISUTRE BUILUP IN THE TERMINAL COMPARTMENTTO DRAIN TO THE SIGNAL WIRE CONDUIT ENTRANCE. DO NOT MOUNT THE TRANSDUCER WITH THE TERMINALCOMPARTMENT COVER ON THE BOTTOM; MOISTURE MAY ACCUMULATE IN THE TERMINAL COMPARTMENTOR PILOT STAGE, PREVENTING PROPER TRANSDUCER OPERATION. THE VERTICAL MOUNT IS MOST EFFECTIVEFOR MOISTURE DRAINAGE IN WET APPLICATIONS.

1

14B7361A6626–1/IL

O-ring gland of the filter-regulator mounting boss. Thefilter-regulator contains a 1/4 NPT output port for asupply gauge. A threaded plug must be installed in thegauge port when a gauge is not used.

Output PressureConnect the output signal line to the Type 846 at theoutput port. The output port is 1/4–18 NPT, as shownin Figure 2-1. The output gauge port can be used asan alternate signal port. If the gauge port is used as asignal port, a threaded plug must be installed in theoutput port.

The output gauge port allows connection of an outputgauge to provide local output signal indication. Theoutput gauge port is 1/4–18 NPT. If an output gauge isnot specified, a threaded plug is shipped with the Type846. The plug must be installed in the output gaugeport when the port is not used.

WARNING

The following conditions may cause fail-ure of the output gauge resulting in per-sonal injury, and damage to the trans-ducer and other equipment:

� pressure beyond the top of thegauge scale.

� excessive vibration.

� pressure pulsation.

� excessive instrument temperature.

� corrosion of the pressure contain-ing parts.

� other misuse.

Refer to ANSI B40.1-1980. Do not use onoxygen service.

Type 846

2–4

Figure 2-2. Typical Type 846 Dimensions With Type 67AFR Filter/Regulator and Gauges (continued)

2.6266.5


3.0677.7

MODULE COVERREMOVAL CLEARANCE


NOTES: THE MOUNTING POSITIONS SHOWN ALLOW ANY MOISUTRE BUILUP IN THE TERMINAL COMPARTMENTTO DRAIN TO THE SIGNAL WIRE CONDUIT ENTRANCE. DO NOT MOUNT THE TRANSDUCER WITH THE TERMINALCOMPARTMENT COVER ON THE BOTTOM; MOISTURE MAY ACCUMULATE IN THE TERMINAL COMPARTMENTOR PILOT STAGE, PREVENTING PROPER TRANSDUCER OPERATION. THE VERTICAL MOUNT IS MOST EFFECTIVEFOR MOISTURE DRAINAGE IN WET APPLICATIONS. IF MOUNTED ON HORIZONTAL PIPE, THE I/P MUST BE ON TOP OF THE PIPE FOR PROPER MOISTURE DRAINAGE.

1

14B7363A6627–1/IL

10.25260.4 MAX

5.38136.7

6.38162.1

PIPE STAND MOUNTED

8.81223.8

2.0050.8

2.3860.5∅

6.19157.2

TYPE 67AFR1/4-18 NPTSUPPLY CONN


9.7/.38∅MOUNTING HOLE4 PLACES

9.69246.1 MAX

6.38162.1

2.6266.5


8.31211.1

2.3860.5

3.5088.9

.7519.0

3.5088.9

5.38136.7 MODULE COVER

REMOVAL CLEARANCE

214B7332A6625–1/IL

Type 846

2–5

Figure 2–3. Dimensions for Type 846 with CENELEC Certifications

TERMINAlCOMPARTMENTCOVER

COVER LOCK

INTERNALHEX DRIVEROUND HEADSCREW (3 mm)

4.75(121) MODULE COVER

HOUSING

EXTERNAL EARTHING CONNECTION, SST TERMINALCLAMP AND SLOTTED M5 SCREW AND SPLITRING WASHER

3.62(92)

6.38(162)

4.75(121)

INCH(mm)

B2465/IL

Electrical Connections

WARNING

Explosions may result in death or seri-ous injury. In explosive atmospheres,remove power and shut off the air sup-ply to the I/P unit before attempting toremove the terminal compartment coveror module cover. Failure to do so couldresult in electrical spark or explosion.

CAUTION

Excessive current can damage thetransducer. Do not connect the Type846 to an input current of more than 100mA.

Signal wiring is brought to the terminal compartmentthrough a 1/2–14 NPT housing conduit connection,shown in Figure 2-1. Where condensate is common,

use a conduit drip leg to help reduce liquid buildup inthe terminal compartment and avoid shorting of theinput signal. Electrical connections are made at theterminal block. An internal grounding lug is provided tofacilitate a separate ground when required. As shownin figure 2-NO TAG, units with CENELEC certificationalso have an external earthing connection. The use ofshielded cable will ensure proper operation in electri-cally noisy environments.

Connect the positive signal lead to the positive termi-nal, marked +. Connect the negative signal lead to thenegative terminal, marked –.

Note

Units with the Remote Pressure Reading(RPR) option may cause interferencewith the analog output signal from someinstrumentation systems. This problemmay be solved by placing a 0.2 microfa-rad capacitor or a HART filter across theoutput terminals.

Type 846

2–6

WARNING

Unscrewing the module cover removespower from the electronics and the out-put signal will be 0.0 psig. An uncon-trolled process may result in death orserious injury. Before removing themodule cover, ensure the device isproperly controlled.

Stroke Port

WARNING

Personal injury and property damagecould result from fire or explosion of ac-cumulated gas. During normal opera-tion, supply air is vented to the atmo-sphere through the stroke port andexhaust port. If a flammable gas is usedas the supply air, the area into which itis vented must be classified as a Divi-sion I hazardous area.

The constant bleed of supply air from the pilot stage isdirected out the stroke port, which is a screened holelocated at the center of the module cover. Figure 2-1shows the location of the stroke port. Before installingthe Type 846, ensure the stroke port is clear. Do notmount the Type 846 in a location where foreign materi-al may cover the stroke port. For information on usingthe stroke port, refer to Section 5 – Troubleshooting.

Exhaust PortThe Type 846 exhausts through a screened port lo-cated beneath the instrument nameplate. Figure 2-1shows the location of the exhaust port. The nameplateholds the screen in place. Exhaust will occur with areduction in output pressure. The Type 846 should notbe mounted in a location where foreign material mayclog the exhaust port.

Signal InterruptionUpon loss of input current, or if input current de-creases below 3.3 �0.3 mA, the output of the directaction unit will decrease to less than 1 psig (0.1 bar).

In the same situation, the output of the reverse actionunit will increase to near supply pressure.

Type 846

3–1

Figure 3-1. Connecting a Current or Voltage Source for Calibration

��

��

��

��

Section 3 CalibrationCalibration of the Type 846 requires either an accuratecurrent generator or an accurate voltage generatorwith a precision 250-ohm, 1/2-watt resistor. Figure 3-1shows how to connect either device.

Calibration also requires a precision output indicatorand a minimum nonsurging air supply of 3 SCFM (5.0Normal m3/hr) at 20 psig (1.4 bar) for standard perfor-mance units. For multirange performance units, the airsupply must be at least 3 psi (0.2 bar) greater than themaximum calibrated output pressure, up to 35 psig(2.4 bar) maximum.

For ease of calibration, the output load volume, includ-ing the output tubing and output indicator, should be aminimum of 2 cubic inches (33 cm3). Review the infor-mation under Signal Interruption in Section 2 beforebeginning the calibration procedure.

Before calibration, determine the type of input (full orsplit range), and the type of output action (direct orreverse). Consult the factory for split range output cal-ibration. Also, determine if the unit offers standard ormultirange performance. The Type 846 supports eightbasic input/output combinations:

Standard Performance

� Full Range Input, Direct Action

� Split Range Input, Direct Action

� Full Range Input, Reverse Action

� Split Range Input, Reverse Action

Multirange Performance

� Full Range Input, Direct Action

� Split Range Input, Direct Action(1)

� Full Range Input, Reverse Action

� Split Range Input, Reverse Action(1)

The input range is selected by changing the position ofa jumper located on the electronic circuit board. Referto Electronic Circuit Board in Section 6, and Figure6-5 for the location and instruction on placement.

CAUTION

Excessive current can damage thetransducer. Do not connect the Type 846to an input current of more than 100 mA.

Standard Performance: Full Range Input,Direct ActionUse the following procedure to achieve a standard 3 to15 psi (0.2 to 1.0 bar) output span for a 4 to 20 mAinput signal:

1. Remove the module final assembly from the hous-ing. Refer to Removing the Module Final Assemblyin Section 6 for an explanation of how to disengagethe module final assembly.

2. Confirm that the unit is direct acting. A green elec-tronic circuit board identifies direct-acting units. Referto Action under the heading Electronic CircuitBoard in Section 6 for more information on direct act-ing units.

3. Position the range jumper in the H position for HighRange. Figure 6-5 shows the circuit board jumperpositions.

4. Replace the module final assembly in the housing.Refer to Replacing the Module Final Assembly inSection 6 for an explanation of how to engage themodule final assembly.

5. Connect the air supply to the air supply port.

6. Connect a precision output indicator to the outputsignal port.

7. Make sure that the output gauge port has an outputgauge or a threaded plug installed. A threaded plug isprovided for units shipped without output gauges.

8. Remove the terminal compartment cover.

9. Connect the current source (or voltage source)positive lead (+) to the terminal block positive (+) and

Type 846

3–2

the current source (250-ohm resistor lead) negativelead (–) to the terminal block negative (–). Refer toFigure 3-1.

CAUTION

Excessive current can damage thetransducer. Do not connect the Type 846to an input current of more than 100 mA.

10. Apply a 4.0 mA (Vm = 1.0 V) signal, and adjustthe zero screw to achieve a 3.0 psig (0.2 bar) output.The output increases with clockwise rotation of thezero screw.

11. Apply a 20.0 mA (Vm = 5.0 V) signal, and adjustthe span screw to achieve a 15.0 psig (1.0 bar) output.The output increases with clockwise rotation of thespan screw.

12. Repeat Steps 10 and 11 to verify and completethe calibration.

Multirange Performance: Full RangeInput, (2) Direct ActionUse the following procedure with a multirange perfor-mance unit to achieve the desired direct action outputspan for a 4 to 20 mA input signal:

1. Perform steps 1 through 9 of the calibration proce-dure for Standard Performance: Full Range Input,Direct Action.

2. Apply a 4.0 mA (Vm = 1.0 V) signal, and adjust thezero screw to achieve the desired lower psi limit of theoutput range. The lower limit must be between 0.5psig (0.03 bar) and 9.0 (0.6 bar). The output increaseswith clockwise rotation of the zero screw.

3. Apply a 20.0 mA (Vm = 5.0 V) signal, and adjustthe span screw to achieve the desired upper psi limitof the output range. The span must be at least 6.0 psi(0.4 bar). The maximum upper limit is 30.0 psig (2.0bar). The output increases with clockwise rotation ofthe span screw.

4. Repeat steps 2 and 3 to verify and complete thecalibration.

Standard Performance: Split RangeInput, Direct Action

4 to 12 mA Input SignalUse the following calibration procedure to produce a 3to 15 psi (0.2 to 1.0 bar) output span for a 4 to 12 mAinput signal:


2. Apply an input of 4.0 mA (Vm = 1.0 V), and adjustthe zero screw to achieve an output of 3.0 psig (0.2bar).

3. Apply an input of 12.0 mA (Vm = 3.0 V), and adjustthe span screw to achieve an output of 15.0 psig (1.0bar).


12 to 20 mA Input SignalUse the following calibration procedure to produce a 3to 15 psi (0.2 to 1.0 bar) output span for a 12 to 20 mAinput signal:

Note

There may be some span interactionwith zero in this range, and the follow-ing steps compensate for this.




4. Maintain the input of 12.0 mA (Vm = 3.0 V), andadjust the zero screw to achieve an output of 3.0 psig(0.2 bar). The unit may not turn down this low; if itdoes not, go to step 7.

5. If the output reaches 3.0 psig (0.2 bar) in step 4,apply an input of 20.0 ma (Vm = 5.0 V) and note theerror (the actual reading versus 15.0 psig). Adjust thespan screw to overcorrect the error by a factor of two.For example, if the reading was 14.95 psig (0.9 bar),adjust the span screw to achieve an output of 15.05psig (1.1 bar).


7. Turn off the air supply. Remove the module finalassembly from the housing. Please the range jumperin the L position for Low Range, as indicated in Figure6-5. Replace the module final assembly. Turn on theair supply.


9. Apply an input of 20.0 mA (Vm = 5.0 V), and notethe error (the actual reading versus 15.0 psig). Adjust

Type 846

3–3

the span screw to overcorrect the error by a factor oftwo. For example, if the reading was 14.95 psig (0.9bar), adjust the span screw to achieve an output of15.05 psig (1.1 bar)


Standard Performance: Full Range Input,Reverse ActionUse the following procedure on reverse action units toachieve a 15 to 3 psig (1.0 to 0.2 bar) output span fora 4 to 20 mA input signal:

1. Perform steps 1 through 9 under Standard Perfor-mance: Full Range Input, Direct Action, except forstep 2. In place of step 2, confirm that the unit is re-verse acting. A red electronic circuit board identifiesreverse-acting units. Refer to Action under the head-ing Electronic Circuit Board in Section 6 for moreinformation on reverse acting units.




Multirange Performance: Full RangeInput (3), Reverse ActionUse the following procedure with a multirange unit toachieve the desired reverse action output span for a 4to 20 mA input signal:

1. Perform steps 1 through 9 of the calibration proce-dure for Standard Performance: Full Range Input,Direct Action, except for step 2. In place of step 2,confirm that the unit is reverse acting. A red electroniccircuit board identifies reverse-acting units. Refer toAction under the heading Electronic Circuit Boardin Section 6 for more information on reverse actingunits.

2. Apply an input of 4.0 mA (Vm = 1.0 V), and adjustthe zero screw to achieve the desired upper psi limit ofthe output range. The 4 mA point must be between 9.0psig (0.6 bar) and 30.0 psig (2.0 bar). The output in-creases with clockwise rotation of the zero screw.

3. Apply an input of 20.0 mA (Vm = 5.0 V), and adjustthe span screw to achieve the desired lower psi limit ofthe output range. The span must be at least 11.0 psi(0.7 bar). The lower limit of the 20.0 mA setting is 0.5

psig (0.03 bar). The output increases with clockwiserotation of the span screw.


Standard Performance: Split RangeInput, Reverse Action

4 to 12 mA Input SignalUse the following procedure on reverse action units toachieve a 15 to 3 psi (1.0 to 0.2 bar) output signal fora 4 to 12 mA input signal:

1. Perform steps 1 through 9 of the calibration proce-dure for Standard Performance: Full Range Input,Direction Action, except for step 2. In place of step2, confirm that the unit is reverse acting. A red elec-tronic circuit board identifies reverse-acting units. Re-fer to Action under the heading Electronic CircuitBoard in Section 6 for more information on reverseacting units.




12 to 20 mA Input SignalUse the following procedure on reverse action units toachieve a 15 to 3 psi (1.0 to 0.2 bar) output signal fora 12 to 20 mA input signal:

Note

There may be some span interactionwith zero in this range, and the follow-ing steps compensate for this.

1. Perform steps 1 through 9 of the calibration proce-dure for Standard Performance: Full Range Input,Direct Action, except for step 2. In place of step 2,confirm that the unit is reverse action. A red electroniccircuit board identifies reverse-acting units. Refer toAction under the heading Electronic Circuit Boardin Section 6 for more information on reverse actingunits.



Type 846

3–4

4. Maintain the input of 12.0 mA (Vm = 3.0 V), andadjust the zero screw to achieve an output of 15.0 psig(1.0 bar). The unit may not turn up this high; if it doesnot, go to step 7.

5. If the output reaches 15.0 psig in step 4, apply aninput of 20 mA, and adjust the span screw to achievea 3.0 psig output. Apply an input of 20 mA (Vm = 5.0V), and note the error (the actual reading versus 3.0psig). Adjust the span screw to overcorrect the errorby a factor of two. For example, if the reading was2.95 psig, adjust the span screw to achieve an outputof 3.05 psig.


7. If the 12.0 mA (Vm = 3.0 V) cannot be adjusted to15.0 psig (1.0 bar) in step 4, turn off the air supply.Remove the module final assembly from the housing.Place the range jumper in the L position for LowRange, as shown in Figure 6-5. Replace the modulefinal assembly. Turn on the air supply.


9. Apply an input of 20 mA (Vm = 5.0 V), and note theerror (the actual reading versus 3.0 psig). Adjust thespan screw to overcorrect the error by a factor of two.For example, if the reading was 2.95 psig, adjust thespan screw to achieve and output of 3.05 psig.


Transporting the Module Final AssemblyThe design of the Type 846 allows the module finalassembly to be removed while the housing is in itsinstalled position. In the event the Type 846 does notfunction properly, an operational module final assem-bly can be taken to the field and exchanged with thenonfunctional module.

After the Type 846 is calibrated in the shop, the mod-ule final assembly can be removed from the housing.At the time the span and zero screws disengage, therewill be minimal effect on the calibrated span. The cali-brated module can now be taken to the field. Ensurethat the span and zero potentiometers are not movedfrom their calibrated positions.

Type 846

4–1

Figure 4-1. Type 846 Block Diagram

4 to 20 MAINPUT

ELECTRONIC CIRCUIT

MAGNETIC ACTUATOR

PILOT STAGE

BOOSTER STAGE

SOLID-STATEPRESSURESENSOR

3 TO 15 PSIOUTPUT, TYPICALA6324/IL

Section 4Principle of OperationThe following paragraphs describe the functional partsof the Type 846. Figure 4-1 shows the block diagram.

Electronic CircuitDuring operation, the input current signal is receivedby the Type 846’s electronic circuit and compared tothe output pressure from the booster stage. A solid-state pressure sensor is part of the electronic circuitand monitors the booster stage output. The silicon-based sensor uses strain gauge thin film technology.

The sensor’s pressure signal is fed to a simple internalcontrol circuit. By using this patented technique, theType 846’s performance is set by the sensor/circuitcombination. Changes in output load (leaks), varia-tions in supply pressure, or even component wear aresensed and corrected by the sensor/circuit combina-tion. Electronic feedback allows crisp dynamic perfor-mance and readily compensates for output changesinduced by vibration.

Note

Because the Type 846 is electronic innature, it is not well-modeled in the loopas a simple resistor in series with an in-ductor. Also it is better thought of as a50-ohm resistor in series with a 6.0 Vvoltage drop, with negligible induc-tance.

Figure 4-2. Detail of Deflector/Nozzle Pilot StageW6287/IL

This is important when calculating the loop load. Whenthe Type 846 is used in series with a microprocessor-based transmitter, the noninductive nature of the Type846 allows digital signals to successfully pass throughundistorted.

Magnetic ActuatorThe electronic circuit controls the level of current flow-ing through the actuator coil, which is located in thepilot/actuator assembly. A change to the level of coilcurrent is made by the electronic circuit when itsenses a discrepancy between the pressure measuredby the sensor and the pressure required by the inputsignal.

The actuator performs the task of converting electricalenergy (current) to motion. It uses a patented, coaxialmoving magnet design optimized for efficient operationand is highly damped at its mechanical resonance. Asilicone rubber diaphragm protects its working mag-netic gaps from contamination.

Pilot StageThe patented pilot stage contains two opposed fixednozzles: the supply nozzle and the receiver nozzle. Italso contains the deflector, which is the moving ele-ment. See Figures 4-2 and 4-3. The supply nozzle isconnected to the supply air and provides a high-veloc-ity air stream. The receiver nozzle captures the airstream and converts it back to pressure. The receivernozzle pressure is the output pressure of the pilotstage.

To vary the pilot output pressure, the high-velocitystream is diverted away from the receiver nozzle bythe deflector, which is a cylindrical, aerodynamic bodylocated between the two nozzles.

In response to a change in actuator coil current, thedeflector is repositioned between the nozzles. There is

Type 846

4–2

Figure 4-3. Deflector/Nozzle Pilot StageOperation (Direct Action)

HIGH OUTPUT PRESSURE

PRESSURE TOBOOSTER STAGE

REGULATEDAIR SUPPLY

��

DEFLECTED NOZZLEFLOW PATTERN

PRESSURE TOBOOSTER STAGE

REGULATEDAIR SUPPLY

A6645/IL

a linear relationship between the coil current and thepilot stage output pressure. For direct action units thepower-off, or fail-safe, position of the top of the deflec-tor is near the center of the stream and results in near-ly zero pilot output pressure. As the coil is energized,the deflector is drawn out of the stream.

For reverse action units, the power-off or fail-safeposition of the deflector is completely out of thestream. The result is maximum pilot output pressure.As the coil is energized, the deflector moves into thestream, resulting in a decreased pilot output pressure.

The deflector material is tungsten carbide, and thenozzles are 316 stainless steel. The nozzles have alarge bore of 0.016 inches (0.41 mm), which providesgood resistance to plugging.

Booster StageThe receiver nozzle pressure controls the boosterstage, which has a poppet valve design. An increasein receiver nozzle pressure positions the valving in thebooster stage to produce an increase in the transduceroutput signal. A decrease in the receiver nozzle pres-sure positions the valving in the booster stage to allowexhaust to occur, decreasing the output signal.

The booster stage operates using a 3:1 pressure gainfrom the pilot stage. High flow rate capability isachieved by large flow area poppet design and internalporting having low flow resistance. The booster stagedesign provides very good stability in high vibrationapplications, and the poppet valve technology providesresistance to plugging.

Type 846

5–1

Section 5 TroubleshootingThe modular design and unitized subassemblies of theType 846 allows for quick and easy troubleshootingand repair. This section presents information on thediagnostic features and procedures for troubleshootingthe Type 846 in service or in the shop.

Diagnostic FeaturesIf a control loop does not perform properly and thecause of malfunction has not been determined, twofeatures of the Type 846 can be used to determine ifthe transducer is at fault: the stroke port and RemotePressure Reading.

Stroke PortThe stroke port provides a way to quickly increase theoutput of the Type 846, giving a rough measure of theunit’s functionality. A hole in the module cover ventsthe constant bleed from the pilot stage. When the holeis covered, pressure at the pilot stage receiver nozzleincreases, which in turn increases the output. Outputpressure will increase to within 2 psi of supply pres-sure for either direct or reverse action. If output pres-sure does not increase to this level, it may indicatethat supply air is not reaching the pilot stage or that apilot stage nozzle is plugged.

Note

If the stroke port diagnostic feature isnot desired, the transducer is availablewith an optional cover that containsmultiple stroke ports, as shown in figure2-1. This prevents increasing the outputby covering the stroke port.

Remote Pressure Reading (RPR)Remote Pressure Reading (RPR) is an optional diag-nostic feature that enables the user to determine theoutput pressure from any location along the signal wirepath. For loop troubleshooting, this allows the user toconfirm the functionality of the Type 846 from a re-mote location.

A frequency signal directly proportional to the outputpressure is superimposed on the input signal loop.The frequency range of the RPR function is 5,000 to8,000 Hz.

A jumper on the circuit board activates the RemotePressure Reading function. Section 6–Maintenanceprovides instruction on positioning the jumper. The

Figure 5-1. HART Communicator ON/OFF Key

A6646/IL

Figure 5-2. HART Communicator Main MenuA6647/IL

Figure 5-3. HART Communicator Frequency Device Menu

A6648/IL

jumper, shown in Figure 6-5, has two positions: N forON, or D for OFF.

Using the HART Communicator to Read the RPRSignal

Use the ON/OFF key to turn the HART Communicatoron and off. When the communicator is turned on, itsearches for a HART compatible device on the 4 to 20mA loop. If a device is not found, then the communica-tor displays the message, ‘‘No Device Found. PressOK.’’ Press OK (F4) to display the Main menu.

If a HART-compatible device is found, the communica-tor displays the Online menu.

When the HART Communicator is not connected to aHART compatible device, the first menu to appear af-ter powering is the Main menu.

From within the Main menu, you can access the Fre-quency Device menu by pressing the 4 key.

Using a Frequency Counter to Read the RPR Signal

A frequency counter also can be used for RemotePressure Reading. The frequency counter displays theRPR output in the same manner as the HART commu-nicator, but the output frequency must be converted tooutput pressure using a simple mathematical formula.To determine the output pressure, subtract 5,000 Hz

Type 846

5–2

Figure 5-4. Wiring Connections for the HART Communicator or a Frequency Counter

CONTROLLER

POWERSUPPLY

FREQUENCYCOUNTER

TESTPINS

POSITIVE

NEGATIVE

GROUND

NOTE: IF A HART COMMUNICATOR IS NOT AVAILABLE, A FREQUENCY COUNTER

CAN BE USED IN ITS PLACE. SEE TEXT TO CONVERT THE FREQUENCY DISPLAYTO TYPE 846 OUTPUT PRESSURE

1

B2466/IL

from the frequency displayed on the frequency count-er, and then divide by 100.

Display Hz – 5, 000 Hz100

psig

5, 311 Hz – 5, 000 Hz100

3.11 psig

Conversion Formula

Example:

Note

The Remote Pressure Reading (RPR)frequency signal has an amplitude of 0.4to 1.0 V peak-to-peak. If other noise (fre-quency) with a comparable or greateramplitude is present on the line, it maymake the RPR frequency signal unread-able.

In-service TroubleshootingA number of simple checks can be made on the Type846 while the unit is in service. Figure 5–5 shows atroubleshooting flowchart.

1. Make sure that the module cover is tight. The covershould be hand–tightened and then advanced 1/4 to1/2 turn (18 to 20 lbf�ft) (24 to 27 N�m).

2. Confirm the general functionality of the unit by us-ing the diagnostic features described earlier in thissection.

3. Confirm that the filter–regulator is not full of wateror oil and that supply air is reaching the unit. The airsupply pressure should be at least 3 psi (0.2 bar)greater than the maximum calibrated output pressure.

4. Confirm that there are no major leaks in the outputsignal line or from the output gauge port.

5. Confirm that there are no obstructions and thescreens are clean in the stroke port or the exhaustport.

WARNING

An uncontrolled process may result indeath or serious injury. Unscrewing themodule cover removes power from theelectronics and the output signal will be0.0 psi. Before removing the modulecover, ensure the device is properlycontrolled.

WARNING

In explosive atmospheres, remove pow-er and shut off the air supply to thetransducer before attempting to removethe terminal compartment cover or mod-ule cover. Failure to do so could resultin electrical spark or explosion.

6. For units with CENELEC Flameproof Certification,remove the cover lock and screw to allow access tothe terminal compartment cover.

7. Remove the terminal compartment cover (seeWarning above), and use a milliammeter, or a digital

Type 846

5–3

Figure 5-5. Type 846 Field Troubleshooting Flowchart

NOTE:AFTER FINAL CORRECTIVE ACTION, CHECK LOOP OPERATION.

IF NOT OK, RESTART TROUBLESHOOTING PROCEDURE. REFER TO REPLACING THE MODULE FINAL ASSEMBLYIN SECTION 6.

1

� ��

� ��

��

� ��

��

��

C0789/IL

voltmeter to confirm that proper input current is sup-plied to the transducer.8. Remove the terminal compartment cover (seeWarning above), and short the loop across the positive(+) and the negative (–) terminals to check the output.The output should be nearly 0 psi. If the output is not 0psi, replace the module final assembly.9. Remove the terminal compartment cover (seeWarning above), and, using a digital voltmeter, checkthe voltage between the positive (+) and negative (–)terminals of the Type 846. The voltage should mea-sure 6.0 to 8.2 V. A lower voltage can indicate a short

in the input wires or defective controller. No voltagecan indicate an open circuit in the control loop. A volt-age of greater than 8.5 volts indicates a problem withthe Type 846, a faulty or corroded connection at thetransducer, or an overcurrent condition. Replace themodule final assembly. If the voltage is still not in theproper range (6.0 to 8.2 V), remove the terminal blockand terminal block connection board. Apply power tothe electrical feedthroughs. (Note the polarity of thefeed–throughs, shown in Figure 6-9.) Recheck thevoltage. If the voltage is in the proper range, replacethe terminal block and terminal block connection

Type 846

5–4

board. If the voltage is still not in the proper range,replace the housing.

10. Prepare to remove the module final assemblyfrom the housing, or to remove the Type 846 from itsmounting bracket. Refer to Module Final Assemblyin Section 6 for instructions on removing the modulefinal assembly from the module housing.

WARNING

An uncontrolled process may result indeath or serious injury. Unscrewing themodule cover removes power from theelectronics and the output signal will be0.0 psig. Before removing the modulecover, ensure the device is properlycontrolled

With the module final assembly removed from thehousing, the following checks can be made.

1. Review the position of the Remote Pressure Read-ing jumper (if so equipped) and range jumper to con-firm that they are placed in the desired position. Referto Electronic Circuit Board in Section 6, and Figure6-5 for the location of these jumpers and instructionson placement.

2. Observe the position and condition of the threemodule O-rings to confirm they make a tight seal.

3. Verify that the O-ring is correctly positioned in thegroove on the flat face of the module cover. Refer toFigure 6-9 for an exploded view.

4. Inspect the porting on the module final assembly todetermine if large amounts of contaminants have en-tered the transducer.

Before making the following checks, disconnect bothsignal wires from the Type 846, and ensure the mod-ule final assembly is removed from the housing.

1. Using an ohmmeter, check the electrical connec-tions in the housing terminal compartment. The circuitshould show an open between the positive (+) andnegative (–) terminals. If not, replace the housing orterminal block and connection board.

2. Use a wire jumper to connect the two electricalfeedthroughs located in the module compartment. Theresistance between the positive (+) and negative (–)terminals in the terminal compartment should be 10ohms. If not, check the electrical feed–throughs forshort or open circuits. If a short or open circuit isfound, replace the housing.

3. With the electrical feed–throughs jumpered asstated above, connect the ohmmeter to either the pos-itive (+) or negative (–) terminal and the grounding lug.

The circuit should show an open. If not, check for ashort to the housing.

4. Remove the module from the module cover andinspect the pilot/actuator assembly for damage orclogging.

Some of the previous troubleshooting steps may beinconvenient to perform in the field. It may be best tomake use of the modular design of the Type 846, andkeep a spare, calibrated module final assembly avail-able for exchange. If the module final assembly is tobe transported to the shop for repair, first remove itfrom the module cover. Attach the spare module finalassembly to the module cover. Refer to Module FinalAssembly in Section 6 for complete instructions. Thenonfunctioning module can then be returned to theshop for troubleshooting.

Troubleshooting in the ShopIf the entire transducer is brought to the shop for trou-bleshooting, then the preceding sequence applies. Ifonly the module final assembly has been brought tothe shop, then use another Type 846 housing as a testfixture. Insert the module into the test fixture. Performthe previous steps (as they apply) of the In-serviceTroubleshooting procedure.

To further aid troubleshooting, the module final assem-bly can be broken down into three subassemblies. Thetroubleshooting sequence consists of exchanging thesubassemblies with known working ones to determinewhich is at fault. The three subassemblies are the pi-lot/actuator assembly, the electronic circuit board, andthe module subassembly. The module subassemblyconsists of the module final assembly with both thepilot/actuator assembly and electronic circuit boardremoved.

1. Remove the pilot/actuator assembly. Refer to Pilot/Actuator Assembly in Section 6 for complete remov-al information.

a. Inspect the nozzles and deflector. If they show abuildup of contaminants, clean the nozzles bygently inserting a wire with a maximum diameter of0.015 inches (0.38 mm). Clean the deflector, if nec-essary, by spraying with LPS� Electro ContactCleaner.

CAUTION

Do not apply force to the deflector barwhile cleaning the nozzles. Doing socould alter the alignment or disable thedeflector bar mechanism.

Type 846

5–5

CAUTION

Do not use chlorinated solvents forcleaning the pilot/actuator assembly.The chlorinated solvents will deterioratethe rubber diaphragm.

b. Make sure the O-rings are lightly lubricated withsilicone grease and properly seated.

c. Reassemble and check operation.

d. If after cleaning the Type 846 does not function,replace the pilot/actuator assembly with a new one.

e. Reassemble and check operation.

2. Remove the electronic circuit board from the mod-ule final assembly. Section 6 – Maintenance describeshow to remove the board.

a. Inspect the O-rings around the sensor for dam-age and replace them if necessary.

b. Check the sensor port and areas around thesensor for foreign material, and clean if necessary.

c. Reassemble and check operation.

d. If the Type 846 does not function, replace theelectronic circuit board with a new one. Refer toElectronic Circuit Board in Section 6 for completeremoval information.

e. Reassemble and check operation.

3. The module subassembly is aligned at the factoryand should not be further disassembled. If the abovesteps fail to produce a working unit, the module subas-sembly is faulty and should be replaced.

Type 846

5–6

Type 846

6–1

Section 6 MaintenanceSection 6 describes the major components, assembly,and disassembly of the Type 846.

WARNING

Use only the procedures and new partsspecifically referenced in this manual.Unauthorized procedures or parts canaffect product performance and the out-put signal used to control a process,and may render the instrument danger-ous. Direct any questions concerningthese procedures or parts to the FisherControls sales office or representative.

Module Final AssemblyThe active mechanical and electrical components ofthe Type 846 are incorporated into a single, field–re-placeable module called the module final assembly, asshown in Figure 6-1. Electrical connection between theterminal compartment and module final assembly ismade by electrical feed–throughs that extend into themodule compartment. The feed-throughs enter sock-ets on the electronic circuit board. The span and zeroscrews extend through the terminal compartment wallinto the module compartment. Connection to the spanand zero potentiometers on the electronic circuit boardis made by Velcro�.

The module final assembly has three separate radialports. The upper port is for supply air, the middle portfor the output signal, and the lower port for exhaust.Three O-rings separate the ports. The two lower O-rings are the same size, and the upper O-ring is slight-ly smaller. Table 6-1 shows Type 846 O-ring sizes.

Note

If the Type 846 will be operated in re-gions where the temperature will be be-low 0 �F (–18�C), ensure that Fisher-sup-plied O-rings are used. They have beenselected to provide cold temperature op-eration.

The module final assembly is attached to the modulecover, which allows insertion and removal, and can beseparated from the module cover for further disassem-bly. A module cover O-ring provides a seal betweenthe module cover and module final assembly. Table6-1 shows the O-ring sizes. A slip ring is locatedaround the module feet. It allows the module cover toturn easily when the module final assembly is beingremoved from the housing.

Table 6-1. Type 846 O-Ring SizesDescription Qty. Size

Module O-rings 12

043042

Pilot/Actuator O-rings 2 006

Circuit Board O-rings 21

016005

Module Cover O-ring 1 238

Terminal Cover O-ring 1 238

Filter–Regulator O-ring 1 208

The module final assembly consists of three majorsubassemblies, as shown in Figure 6-1. They are theelectronic circuit board, pilot/actuator assembly, andmodule subassembly.

Removing the Module Final AssemblyThe module final assembly is attached to the modulecover. Removing the module cover automatically re-moves the module final assembly from the housing.When the module cover is unscrewed, the electricalfeed-throughs and span and zero adjustments auto-matically disengage. The internal air ports are alsodisengaged. The air supply to the transducer shouldbe turned off to prevent uncontrolled air loss throughthe housing.

WARNING

Unscrewing the module cover removespower from the electronics and the out-put signal will be 0.0 psig. An uncon-trolled process may result in death orserious injury. Before removing themodule cover, ensure the device isproperly controlled.

WARNING

Explosions may result in death or seri-ous injury. In explosive atmospheres,remove power and shut off the air sup-ply to the transducer before attemptingto remove the terminal compartmentcover or module cover. Failure to do socould result in electrical spark or explo-sion.

Use the following steps to remove the module finalassembly from the housing and module cover:

1. Shut off the air supply. For units with CENELECFlameproof Certification, remove the cover lock andscrew to allow access to the terminal compartmentcover. Unscrew the module cover. When the modulecover threads clear the housing, slowly pull on thecover, and the module final assembly will graduallycome out of the housing.

Type 846

6–2

Figure 6-1. Type 846 Exploded View

ELECTRONIC CIRCUIT BOARD SCREWS

ELECTRONIC CIRUIT BOARD

SENSOR SEAL

MODULE SUBASSEMBLY

PILOT/ACTUATORASSEMBLY

SCREWS

PILOT/ACTUATORASSEMBLY SCREWS

PILOT/ACTUATORASSEMBLY O-RINGS

MODULE O-RINGS

ELECTRONICCIRCUIT BOARD O-RINGS

TERMINAL COVER

MODULE HOUSING

V-GROOVEALIGNMENTMARK

MODULE FINAL ASSEMBLY

V-GROOVE

MODULE FEET

SLIP RING

O-RING

MODULE COVERINDICATING BOSS

ALIGNMENT KEY

MODULE COVER

COVER SLOT (2)

O-RING CLIP

RETAINING CLIP (2)

STROKE PORTSCREEN

KEY SLOT

C0790/IL

Type 846

6–3

Figure 6-2. Alignment Key Above Module Cover Indicating Boss

MODULEALIGNMENTKEY

INDICATINGBOSS

A6649/IL

Note

The module and the housing are de-signed for minimal clearance; therefore,patience may be required while pullingon the cover. Time must be allowed forrelease of the vacuum effect betweenthe housing and module. If the modulebecomes tilted and cannot be removed,reinsert it completely into the housingand fully engage the module coverthreads. Then proceed again with re-moval, ensuring that you pull slowly in astraight line.

Support both the module cover and the module finalassembly as it comes out of the housing. This is toprevent dropping them, should they become detachedaccidentally.

CAUTION

Do not grip the module cover threads.The threads are sharp and may causeminor injury. Wear gloves when remov-ing the module cover.

2. Prepare to remove the module final assembly fromthe module cover. Align the module feet with the twointerior cover slots. To accomplish this, identify theindicating boss on the module cover, shown in Figure6-2.

Grasp the module cover with one hand and the mod-ule final assembly with the other hand. Rotate themodule final assembly so that the module alignmentkey is directly above the indicating boss on the modulecover. Figure 6-2 shows the module alignment key andthe indicating boss. The module feet are now alignedwith the cover slots.

3. Remove the module final assembly from the mod-ule cover. To accomplish this, hold the cover steady,

Figure 6-3. Removing the Module Final Assembly from theModule Cover

A6650/IL

and push the module final assembly in the direction ofthe module cover indicating boss. At the same time, liftthe opposite foot of the module final assembly out ofthe cover slot, as shown in figure 6-3.

Replacing the Module Final AssemblyUse the following procedure to attach the module cov-er and replace the module final assembly:

1. Ensure that the electronic circuit board and the pilotactuator assembly provide the desired action (direct orreverse). See the Electronic Circuit Board and Pilot/actuator Assembly Action descriptions later in thissection.

2. Ensure that the slip ring is in place around the feetof the module final assembly. The module cover O-ringshould be lightly lubricated with silicone grease andplaced in the O-ring gland. The stroke port screenshould be clean and in place.

WARNING

Explosions may cause death or seriousinjury. Do not operate the Type 846 withthe CENELEC flameproof options at asupply pressure in excess of 20 psi (1.4bar). Doing so invalidates the CENELECflameproof certifications and could al-low flames to spread from the unit po-tentially igniting and causing an explo-sion (see figure 6-4).

Note

The module cover O-ring must be in theO-ring gland, not down on the threadsof the cover. This will ensure propersealing of the pilot pressure area.

3. Position the retaining clips in the module cover sothey are ready to accept the feet of the module finalassembly. Ensure the leaves on the retaining clips arefacing up. Figure 6-1 shows the correct orientation.

Type 846

6–4

Figure 6-4. CENELEC Flameproof Module

A6651/IL

4. Insert one of the module feet into a cover slot, andpush on the module final assembly to compress theretaining clip. Insert the opposite foot into the oppositecover slot, and rotate the module 90 degrees in themodule cover to secure it in place.

5. Ensure that the three module O-rings are in theO-ring glands and are lightly lubricated with siliconegrease. Inspect the O-rings to ensure that they are nottwisted or stretched.

6. Ensure that the module cover threads are lubri-cated with Low Temperature Lubriplate.

7. Prepare to insert the module into the housing. Alignthe V-groove located on the module final assemblywith the indicating mark located on the nameplate.This positions the alignment key with the key slot. Fig-ure 6-1 shows the location of the V-groove and theindicating mark.

8. Insert the module, engage the module coverthreads, and screw on the module cover. The modulefinal assembly will automatically engage the electricalfeed-throughs and span and zero screws.

9. Hand tighten the module cover as much as pos-sible. Use a wrench or long screwdriver shaft to tight-en the module cover an additional 1/4 to 1/2 turn (18to 20 lbf�ft) (24 to 27 N�m). For units with CENELECFlameproof Certification, make sure the cover lockand screw have been securely re-installed. The screwaccepts a 3 mm hex drive.

RPR OFF

Figure 6-5. Circuit Board Jumper Positions

HIGHRANGE

LOWRANGE

RPR ONNOTE:

RPR JUMPER ONLY ON UNITS WITH REMOTEPRESSURE READING (RPR) OPTION1

A6652/IL

Note

When the module cover is tightened,connection is made with the electricalfeedthroughs and span and zeroscrews, and the module final assemblyO-rings become seated. Failure to fullytighten the module cover may preventthe Type 846 from operating properly.

Electronic Circuit BoardThe Type 846 electronic circuit board is located on topof the module final assembly, as shown in Figure 6-1.Beneath the circuit board and permanently attached toit is the pressure sensor. Two jumpers on the circuitboard control various functions of the transducer. Fig-ure 6-5 shows the location of these jumpers.

Optional Remote Pressure Reading (RPR)JumperRemote Pressure Reading (RPR) is an optional diag-nostic feature that enables the operator to determinethe output signal of the Type 846 from any locationalong the signal wire path. The Type 846 generates afrequency signal that can be received by a HART�

Communicator, or a frequency counter. Operation ofthe RPR feature is jumper-selectable, in units soequipped. The RPR feature operates when the jumperis located in the N position on the circuit board. With

Type 846

6–5

the jumper in the D position, the RPR feature does notoperate. When the RPR feature is included, the Type846 is shipped with the RPR jumper in the N position.For more information about the RPR feature, refer toRemote Pressure Reading (RPR) in Section 5.

Note

When operating Type 846 transducers inseries, only one unit may be configuredfor Remote Pressure Reading. Activat-ing the RPR feature in two units will re-sult in an unusable RPR signal.

Range JumperThe range jumper is positioned according to the cal-ibration specified. All full span calibrations and somesplit range calibrations can be accomplished with therange jumper in the High Range position. Some splitrange calibrations require the jumper to be in the LowRange position. For more information about the rangejumper, refer to Standard Performance: Split RangeInput, Direct Action in Section 4.

ActionFor direct action units, output changes directly with acorresponding change in input. For example, as theinput increases from 4 to 20 mA the output increasesfrom 3 to 15 psi (0.2 to 1.0 bar). Direct action circuitboards are green in color.

For reverse action units, output changes inversely witha change in input. For example, as the input increasesfrom 4 to 20 mA the output decreases from 15 to 3 psi(1.0 to 0.2 bar). Reverse action circuit boards are redin color.

Upon loss of input current, or if input current de-creases below 3.3 �0.3 mA, the output of the directaction unit decreases to less than 1 psig (0.1 bar). Inthe same situation, the output of the reverse actionunit increases to near supply pressure.

Removing the Electronic Circuit BoardThe electronic circuit board is connected to the modulefinal assembly by five mounting screws. The circuitboard must be removed to inspect the pressure sen-sor located beneath it. To remove the circuit board,remove the five mounting screws and pull upward onthe plastic board standoff.

CAUTION

Standard electronic assembly handlingprocedures apply. Do not attempt to re-

Figure 6-6. Positioning the Pressure Sensor

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ELECTRONICCIRCUITBOARD

ELECTRONICCIRCUITBOARD

MANIFOLD

MANIFOLD

SOLID STATEPRESSURE SENSOR

A6653/IL

move the circuit board by pulling on thecomponents. Doing so could weakenthe connections and disable the elec-tronics.

Be careful when handling the pressure sensor locatedbeneath the circuit board. The pressure sensor leadframe is bent to allow the pressure sensor to fit prop-erly in the sensor cavity of the module final assembly,and to maintain flush contact with the pressure sensormanifold.

Three O-rings accompany the pressure sensor. TwoO-rings of the same size are located on each side ofthe pressure sensor. A third, smaller O-ring is posi-tioned in the beveled O-ring gland of the module sub-assembly. Table 6-1 shows the O-ring sizes. It is ac-ceptable to gently bend the pressure sensor awayfrom the pressure sensor manifold to access the sen-sor O-ring and confirm that the pressure ports areclear.

Replacing the Electronic Circuit Board1. Verify that the circuit board is green for assemblyinto a direct action unit, or red for assembly into a re-verse action unit.

2. Ensure that the three O-rings are in the properposition. The small O-ring is positioned in the beveledO-ring gland of the module sub-assembly. The twosensor O-rings are each positioned on the shouldersof the sensor. They should be lightly lubricated withsilicone grease.

3. Ensure that the pressure sensor is correctly posi-tioned against the manifold. The pressure sensorshould be centered and in contact with the manifold,as shown in Figure 6-6.

4. Position the circuit board on the module subassem-bly. Ensure that the circuit board mounting holesmatch those on the module subassembly. Place thethree long screws in the mounting holes adjacent tothe pressure sensor.

Type 846

6–6

Figure 6-7. Pilot/Actuator Assembly (Bottom View)

ALIGNMENTKEY

RUBBERDIAPHRAGM

MOUNTINGSCREWS

A6654/IL

5. Place the two short screws in the remaining mount-ing holes. Tighten the three long screws first, thentighten the remaining two screws.

Pilot/Actuator AssemblyThe pilot/actuator assembly is located at the bottom ofthe module final assembly, as shown in Figure 6-1. Itis a unitized assembly consisting of the coil, magnet,and spring of the actuator, and the deflector andnozzles of the pilot stage. Two O-rings are part of thepilot/actuator assembly. Table 6-1 shows the O-ringsizes. They are located in the beveled O-ring glands ofthe module subassembly, adjacent to the nozzles. Thepilot/actuator assembly is held in place by four mount-ing screws.

ActionA blue rubber diaphragm under the deflector bar andnozzle area identifies the direct action pilot/actuatorassembly. A red diaphragm under the nozzle areaidentifies the reverse action pilot/actuator assembly.Figure 6-7 shows the bottom view of the pilot/actuatorassembly.

Removing the Pilot/Actuator AssemblyTo remove the pilot/actuator assembly, disengage thefour mounting screws, and gently pull the assemblyout of the module subassembly. It is useful to gentlygrip the pilot/actuator framework with a pair of pliers.

WARNING

An uncontrolled process may result indeath or serious injury. Do not attemptto remove the pilot/actuator assemblyby gripping or pulling on the deflector

Figure 6-8. Cleaning the Nozzles

A6655/IL

DEFLECTOR BAR

WIRE WIRE

PLASTIC HOUSING

or nozzles. Doing so could alter thealignment or disable the deflector/nozzle mechanism.

The assembly can be inspected for a buildup of for-eign material. The nozzle passage-ways should beclear, and the deflector should be clean. The deflectorcan be cleaned by spraying it with LPS� Electro-Con-tact Cleaner. The nozzles can be cleaned by gentlyinserting a wire with a maximum diameter of 0.015inches (0.38 mm).

� Insert the wire into each nozzle separately fromthe outside as shown in figure 6-8.

� Do not try to put the wire through both nozzles si-multaneously.

� Do not push the wire on the deflector bar.

CAUTION

Do not apply force to the deflector barwhile cleaning the nozzles. Doing socould alter the alignment or disable thedeflector mechanism.

CAUTION

Do not use chlorinated solvents forcleaning the pilot/actuator assembly.The chlorinated solvents will deterioratethe rubber diaphragm

Replacing the Pilot/Actuator Assembly1. Verify that the rubber diaphragm under the nozzlearea is blue for pilot/actuators inserted into a directaction unit, or red for pilot/actuators inserted into areverse action unit.

2. Inspect the pilot/actuator assembly cavity in themodule final assembly to ensure that it is clean.

3. Lightly lubricate the two O-rings with siliconegrease, and place them in the beveled O-ring glands.

Type 846

6–7

O-rings between the pilot/actuator assembly and themodule should be installed justified to the lower portionof the O-ring gland. The air passageway should bevisible through the O-ring inside diameter if properlypositioned.

4. Prepare to insert the assembly by aligning the keyon the pilot/actuator assembly with the key slot in themodule subassembly.

5. Insert the assembly into the module subassembly,and engage the four mounting screws.

Module SubassemblyThe module subassembly, shown in Figure 6-1, con-sists of the module final assembly with both the elec-tronic circuit board and pilot/actuator assembly re-moved. The module subassembly contains the portingand valving for the booster stage.

Note

The module subassembly is aligned atthe factory and should not be furtherdisassembled. Disassembling the mod-ule subassembly may result in perfor-mance outside specifications.

Terminal CompartmentThe terminal compartment contains the terminal block,terminal block connection board, span and zeroscrews, electrical feed–throughs, and internal ground-ing lug, as shown in Figure 6-9. The terminal blockconnection board is attached to the terminal block andto the electrical feedthroughs.

Separate test points are provided that have a 10-ohmresistor in series with the signal negative (–) terminal.The test points allow the input current to be deter-mined with a voltmeter without disconnecting a signallead. A 4 to 20 mA span produces a 40 to 200 mV dcvoltage drop across the 10–ohm resistor. The testpoints can accommodate different connections, includ-ing alligator clips and E–Z hooks.

The terminal block and terminal block connectionboard can be removed by disengaging the two termi-nal block mounting screws. Lubricate the terminalcompartment cover threads with CICO� Anti–SeizingPaste 1200, Never–Seez� Compound, or Low Tem-

Figure 6-9. Terminal Compartment Exploded View

A6656/IL

ELECTRICALFEEDTHROUGHS

TERMINALBLOCK

TERMINAL BLOCKCONNECTIONBOARD

TEST PINS

ZERO AND SPANSCREWS

GROUNDINGLUG

perature Lubriplate. See Table 6-1 for the size of theterminal compartment cover O-ring.

Exhaust and Stroke Port ScreensTwo identical screens, the exhaust port screen and thestroke port screen, allow air to vent to the outside en-vironment from the Type 846. The exhaust port screenis located behind the nameplate. Removing the twonameplate screws and rotating the nameplate to theside allows access to the exhaust port screen. Figure7-1 shows an exploded parts view.

The stroke port screen is located at the center of themodule cover. Removing the module final assemblyfrom the housing and then from the module cover al-lows access to the stroke port screen. Removing theModule Final Assembly earlier in this section de-scribes this procedure. Figure 7-1 shows an explodedparts view.

Type 846

6–8

Type 846

7–1

Section 7 Parts ListWhenever corresponding with the Fisher sales officeor sales representative about this equipment, alwaysmention the transducer serial number. When ordering

replacement parts, refer to the 11-character Fisherpart number of each required part. Figure 7-1 showsthe key numbers for all replaceable parts.

Table 7-1. Parts List Cross ReferenceKey No. Description Rosemount Part No. Fisher Part No. Spares Category (8)

Module Final Assembly(4)

Standard PerformanceDirect ActionReverse Action

Multirange PerformanceDirect ActionReverse Action

03311-0298-000403311-0298-0005

03311-0298-000803311-0298-0009

13B8788 X01213B8789 X012

13B8790 X01213B8791 X012

BB

BB

9Module Subassembly(1)(4)

Standard Performance OnlyStandard Configuration 03311-0409-0002 13B8792 X012 B

12

Pilot/Actuator Assembly(1)

Standard Performance OnlyDirect ActionReverse Action

03311-0410-000103311-0410-0002

13B8793 X01213B8794 X012

BB

8

Circuit Board Assembly(1)

Standard Performance OnlyDirect ActionReverse Action

03311-0411-000503311-0411-0006

13B8795 X01213B8796 X012

BB

3 Housing(2) 03311-0412-0008 13B8797 X012 C

15Module Cover

Single Stroke PortMultiple Stroke Ports

03311-0341-000303311-0341-0004

13B8798 X01213B8799 X012

CC

1 Terminal Compartment Cover 03311-0413-0002 13B8800 X012 C

5 Terminal Block Kit(3) 03311-0414-0002 13B8801 X012 B

16 Screens (12/pkg) 03311-0415-0001 13B8802 X012 B

10117

2, 21, & 23

O–RingsModule (5/kit)(5)

Pilot/Actuator (5/kit)(5)

Circuit Board (5/kit)(5)

Cover [12 O–rings (keys 2 and 23), 12 slip rings (key 21)](5)

03311-0416-000103311-0417-000103311-0418-000403311-0421-0001

13B8803 X01213B8804 X01213B8805 X01213B8806 X012

BBBB

136

14

ScrewsPilot/Actuator (3/kit)(5)

Circuit Board (3/kit)(5)

Nameplate (3/kit)(5)

03311-0417-000203311-0418-000103311-0419-0001

13B8807 X01213B8808 X01213B8809 X012

CCC

18 Retaining Clips (3/kit)(5) 03311-0420-0001 13B8810 X012 C

Output gaugeTire ValvePipe Plug (use if gauge or tire valve isnot specified)

— — —— — —

— — —

see following table1H4470 X0012

1C3335 28992

AA

C

Universal Mounting Kits(6)

Painted CS Bracket, CS Nuts/BoltsPainted CS Bracket, SST Nuts/Bolts316 SST Bracket, SST Nuts/Bolts

— — —— — —

03311-0404-0004

13B8811 X01214B4978 X01214B4977 X012

CCC

Universal Mounting kit for transducerw/SST housing(7) 03311-0404-0003 14B4979 X012 C

1. Includes O–rings.2. Includes housing, span and zero screws, electrical feedthroughs, and grounding lug.3. Includes terminal block, connection board (key 4), and screws.4. For units with approvals other than CENELEC Flameproof, use standard module.5. #/kit indicates number of tranducers that may be serviced.6. Use universal mounting kit for surface or bulkhead mounting transducer with aluminum housing.

7. This mounting kit contains 316 SST bracket, nuts and bolts, plus aSST plate to support the additional weight of the SST housing.8. Spares Catetories

Category A – Recommend 1 spare part per 25 transducersCategory B – Recommend 1 spare part per 50 transducersCategory C – None normally required.

Type 846

7–2

Figure 7-1. Type 846 Exploded Parts Drawing

B2467/IL

Type 846

7–3

Figure 7-1. Type 846 Exploded Parts Drawing (continued)

B2468 / IL

Type 846

7–4

Output and Supply Gauges

RangeOutput Gauge Supply Gauge

RangeBrass SST Brass SST(2)

Triple Scale0-30 psi/0-0.2 MPa/0-2 bar0-60 psi/0-0.4 MPa/ 0-4 bar

11B8579 X02211B8579 X032

11B9639 X01211B9639 X022

11B8580 X06211B8580 X022

11B9639 X01211B9639 X022

Dual Scale0-30 psi/0-2 kg/cm2

0-60 psi/0-4 kg/cm211B8579 X06211B8579 X072

11B8583 X032(3)

— — —11B8580 X05211B8579 X072(1)

11B8583 X032(3)

— — —1. Adding a brass, dual scale, 0 - 60 psi/0-4 kg/cm2 supply gauge to an existing unit also requires an elbow, part number 1J1082 28992.2. Adding a stainless steel supply gauge to an existing unit also requires a SST elbow, part number 1A9132 X0022.3. Adding a stainless steel, dual scale, 0-30 psi/0-2 kg/cm2 gauge to an existing unit also requires a bushing, part number 1E2537 K0012.

Parts For Integrally Mounted 67 SeriesFilter RegulatorKey Description Part Number

8* Supply Gauge See following table8 Tire Valve (use only when specified) 1H4470 X0012

11 Cap Screw (2 req’d)steel pl 1C3988 24052SST 1C3988 X0022

12* O-ring, nitrile 13B9462 X012108 Pipe plug, steel (use if gauge or tire valve

is not specified) 1A7675 24662

316 SST 1A7675 35072

*Recommended spare parts

Type 846

8–1

Section 8Loop SchematicsThis section includes loop schematics required for wir-ing of intrinsically safe installations. If you have anyquestions, contact your Fisher Controls sales repre-sentative or sales office.

13B8779-A/ doc

CSA Schematics

Type 846

8–2

FM Schematics

13B8780-A/ doc

For information, contact Fisher Controls:Marshalltown, Iowa 50158 USACernay 68700 France Sao Paulo 05424 BrazilSingapore 0512

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Printed in U.S.A.

Documents

Type 846 Electro-Pneumatic Valve Positionerlinearcontrols.net/intranet2/Fisher/Fisher/Manuals/D012077.pdftested per SAMA Standard PMC 33.1C–1978, change in steady–state deviation