END-OF-TRAIN SENSE AND BRAKE UNIT · END-OF-TRAIN SENSE AND BRAKE UNIT R An ANSALDO Affiliated Company Installation Operation. TABLE OF CONTENTS SM 6496 4/96 i I. INTRODUCTION.....1-1

SERVICE MANUAL 6496645 Russell StreetBatesburg, SC 29006

Digitair Model 6695

April 1996COPYRIGHT 1996, UNION SWITCH & SIGNAL INC.PRINTED IN USA

UNION SWITCH & SIGNAL

END-OF-TRAIN SENSE AND BRAKE UNIT

R

An ANSALDO Affiliated Company

Installation

Operation

TABLE OF CONTENTS

SM 6496 4/96 i

I. INTRODUCTION.......................................................................................................... 1-1

1.1 PURPOSE OF MANUAL.............................................................................................. 1-11.2 DESCRIPTION............................................................................................................. 1-11.2.1 General ......................................................................................................................... 1-11.2.2 Components ................................................................................................................. 1-21.2.2.1 Unit Housing ................................................................................................................. 1-21.2.2.2 Coupler Clamp.............................................................................................................. 1-31.2.2.3 Brake Line Connection ................................................................................................. 1-31.2.2.4 External Test Button and Display Window ................................................................... 1-31.2.2.5 Highly Visible Marking Device (Marker Light) .............................................................. 1-41.2.2.6 Unit Identification .......................................................................................................... 1-41.2.2.7 Batteries........................................................................................................................ 1-41.2.2.8 Antenna ........................................................................................................................ 1-41.2.2.9 Brake Pipe Hose Retention Chain or Steel Cable........................................................ 1-41.2.2.10 RS-232 Port.................................................................................................................. 1-51.2.2.11 Brake Solenoid ............................................................................................................. 1-51.2.2.12 Motion Sensor............................................................................................................... 1-51.2.2.13 Transceiver................................................................................................................... 1-51.2.2.14 Pressure Sensor........................................................................................................... 1-51.2.2.15 Temperature Sensor..................................................................................................... 1-51.2.2.16 Microcontroller Board ................................................................................................... 1-51.3 SPECIFICATIONS........................................................................................................ 1-61.4 FUNCTIONAL BLOCK DIAGRAM ............................................................................... 1-7

II. INSTALLATION ........................................................................................................... 2-1

2.1 INTRODUCTION.......................................................................................................... 2-12.2 BATTERY INSTALLATION .......................................................................................... 2-12.2.1 NiCad Battery Installation ............................................................................................. 2-12.2.2 Lead Acid Battery Installation ....................................................................................... 2-32.3 UNIT MOUNTING AND ENVIRONMENT.................................................................... 2-32.4 UNIT TESTING............................................................................................................. 2-42.4.1 Diagnostics ................................................................................................................... 2-72.5 UNIT INITIALIZING and ARMING................................................................................ 2-72.5.1 One-way Operation and Initializing............................................................................... 2-72.5.2 Two-way Operation and Arming ................................................................................... 2-82.5.3 Automatic One-Way/Two-Way SBU Operation............................................................ 2-92.5.4 SBU LED Pressure Display Enable on Reception of Cab Message ............................ 2-92.5.5 User Definable Password Protection.......................................................................... 2-102.5.6 AEI Tag Installation .................................................................................................... 2-102.6 AEI TAG INSTALLATION (Optional).......................................................................... 2-11

TABLE OF CONTENTS

ii SM 6496 4/96

III. OPERATION ................................................................................................................ 3-1

3.1 GENERAL OPERATION .............................................................................................. 3-13.1.1 Unit Power Up............................................................................................................... 3-13.1.2 Unit Power Down.......................................................................................................... 3-13.1.3 Brake Pressure Monitoring........................................................................................... 3-23.1.4 Motion and Direction Sensor ........................................................................................ 3-23.1.5 Battery Monitoring......................................................................................................... 3-23.2 EMERGENCY OPERATION ........................................................................................ 3-33.2.1 Emergency Brake Application ...................................................................................... 3-33.2.2 Emergency Brake Application (Manual Reset)............................................................. 3-43.2.3 Diagnostic Unit Software .............................................................................................. 3-43.2.3.1 Keys.............................................................................................................................. 3-43.2.3.2 Connecting to the End Unit........................................................................................... 3-43.2.3.3 Main Menu.................................................................................................................... 3-53.2.3.4 Diagnostics Items Menu ............................................................................................... 3-53.2.3.5 System Information....................................................................................................... 3-73.2.3.6 Configuration Items Menu ............................................................................................ 3-73.2.3.7 Set ID Code .................................................................................................................. 3-83.2.3.8 Set Message Protocol Type.......................................................................................... 3-93.2.3.9 Pressure Sensor Calibration Menu ............................................................................ 3-103.2.3.10 Set Password Protection Screen................................................................................ 3-10

LIST OF ILLUSTRATIONS

Figure 1-1 Two-Way Telemetry ..................................................................................................... 1-1Figure 1-2 Model 6695 SBU Features ........................................................................................... 1-2Figure 1-3 End Unit Functional Block Diagram.............................................................................. 1-7Figure 2-1 Jumper Configuration for Batteries............................................................................... 2-2Figure 2-2 Unit Mounting................................................................................................................ 2-3Figure 2-3 AEI Tag Installation .................................................................................................... 2-11

Section I INTRODUCTION

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1.1 PURPOSE OF MANUAL

This manual provides information on the installation and operation of the DIGITAIR� Model 6695Sense and Brake Unit (SBU) End-of-Train (EOT) Monitor system. The manual also providesinformation on troubleshooting, diagnostics and field maintenance.

1.2 DESCRIPTION

1.2.1 General

The DIGITAIR Model 6695 is a two-way telemetry device operating in the 450 MHz band. The Model6695 SBU is clamped to the coupler of the last car of the train, with its brake line sensing hoseattached to the brake line gladhand.

The Model 6695 SBU performs two important functions for the locomotive operator:

�� provides a telemetry unit that monitors and reports on the following conditions atthe rear of the train:

-the brake line pressure-the state of motion of the last car-the status of the Highly Visible Marker (HVM) Device-battery status

�� provides a back-up emergency braking device

The Model 6695 measures the conditions at the end of the train and radios them from the “End Unit” tothe “Cab Unit” of the locomotive. The information is then decoded and displayed for the locomotiveoperator.

The Model 6695 SBU features an air release brake valve that serves as a back-up emergency brakingdevice, NOT as a braking improvement device. The locomotive operator can activate the valve in theModel 6695 SBU to vent the brake line from the rear if releasing the brake pressure from thelocomotive fails to slow the train.

The Model 6695 is compatible with all Cab Units employing the American Association of Railroads(AAR) End-of-Train message protocol. It meets or exceeds the guidelines of the AAR along with theFederal Railroad Administration (FRA), the Federal Communications Commission (FCC), and theCanadian Department of Communications (DOC) regulations.

HVM

6695 SBU

BRAKE PIPE AIR

LAST CAR

450-475 mHz RF LINK

-BRAKE PRESS.-BATTERY STATUS-HVM STATUS-CAR MOTION

VEHICLEBATT.

ODOMETERINPUT (OPT.)

CAB UNIT

LOCOMOTIVE

Figure 1-1. Two-Way Telemetry


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1.2.2 Components

The diagram below depicts a typical version of the Model 6695 SBU showing its external components.The Exhaust Valve & Gladhand, Air Hose, Battery Compartment, and Coupler Clamp are available inother configurations to accommodate specific customer requirements.

Exhaust Valveand

Gladhand

LargeReflective Surfaces

Test Button

Plastic Holderfor

AEI and ID Tags

DisplayWindow

Unit Housing

Handle

Protective Ribsaround

Battery DoorLatches

Battery Door

LED Marker Light

Antenna

Coupler Clamp

Air Hose

Figure 1-2. Model 6695 SBU Features

1.2.2.1 Unit Housing

The Model 6695 SBU features a fully-unitized, high-strength aluminum alloy casting. The housingprotects the internal components of the End Unit from the severe environment it encounters, such asvibration, impact and handling abuse. The latest technology in gasket material gives the Model 6695SBU a higher degree of water resistance. A water-resistant conformal coating is applied to all PrintedCircuit Boards (PCBs) along with gold-plated connectors for additional protection.

The Model 6695 SBU is designed to be lightweight with enhanced balance and a handle for handcarrying. The unit features highly-reflective 3M� Diamond Grade reflective tape on the trailing side toincrease night visibility for approaching train crews.

The unit also features a conveniently located battery compartment door on the reflector side of the unit.Within the battery compartment is an RS-232 serial data port which connects to a PC, so technicianscan perform diagnostics, calibration and tests without opening the main case.


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1.2.2.2 Coupler Clamp

A compact coupler clamp at the base of the Model 6695 SBU allows quick, secured mounting of theunit and a locking mechanism for security. The unit’s center of gravity is located close to the coupler,minimizing loading on the mounting clamp. The Model 6695 SBU will be clear of damage from helperlocomotives equipped with snow plows.

Two types of Coupler Clamps are available as follows:

1. A “key” shaped handle used to tighten and loosen the coupler clamp. This handle has two squareholes which align with a Battery Door lever and accept a standard railroad padlock. The padlockcan be used to reduce theft of the batteries and also serves to prevent the SBU from vibrating loosefrom the coupler.

2. A crank handle incorporating a ratchet type tightening mechanism. Once secured to the coupler, thisCoupler Clamp will not vibrate loose, even if a padlock is not used. A Battery Door lever isprovided, however, and accepts a standard railroad padlock to reduce theft of the batteries.

1.2.2.3 Brake Line Connection

The Model 6695 SBU monitors brake line air pressure via its gladhand connection to the brake line.The brake line supplies the air to run the brake system for each car and provides the control forapplying and releasing the brakes. The brake line runs the entire length of the train. Brake line air issupplied to the Model 6695 SBU through a hose. The hose is a high-pressure, internally steel braidedflexible hose with a standard gladhand fitting. In emergency situations, the operator can request anemergency brake command through the Model 6695 SBU.

Units equipped for 2-way operation include a differential pressure type Exhaust Valve which isavailable in two configurations:

1. Exhaust Valve mounted directly to the bottom of the SBU and fitted with a standard diameter AARbrake pipe hose and gladhand.

2. Exhaust Valve mounted at the end of a small diameter air hose which screws into the bottom of theSBU.

The SBU is also available in a Dual Pressure configuration which is fitted with an additional air hoseand gladhand. This provides for monitoring of air pressures other than the main brake pipe pressure.

1.2.2.4 External Test Button and Display Window

The external test button allows the user to apply power if no air is applied and to transmit the airpressure and status information each time the button is pressed. It is easily accessible and can bepushed by someone wearing heavy gloves.

A 4-character LED display is located near the external test button and is easily visible from the trackside. It displays the air pressure, telemetry battery status, and other diagnostic information. Tomaximize the visibility of the display window, the lens is angled downward to minimize the surfacereflections coming from behind the user.


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1.2.2.5 Highly Visible Marking Device (Marker Light)

NOTE

In areas where the Marker Light is not required, it is replaced with a highvisibility reflector.

The Highly Visible Marker Light (HVM), also referred to as the Marker Light, is a visual warning deviceindicating the end of the train. Any time the Marker Light changes state, the End Unit sends statusmessages to the Cab Unit to indicate the change in status.

The Marker Light consists of a red flashing light operated by a photoelectric sensor which enables thelight. When enabled, the light flashes at a rate of about once per second. LEDs provide a brilliant lightoutput pattern. Even if several LEDs fail, a high level of light intensity is maintained. The LED lightsource draws far less power than previous HVM equipment, a major factor in the extended battery life.

1.2.2.6 Unit Identification

The Model 6695 SBU features two identification forms, a printed label and attached plastic pocketholder for both the Automatic Equipment Identification (AEI) tag and an aluminum strip with the five-digit AAR assigned ID number printed on it.

1.2.2.7 Batteries

The UHF version of the Model 6695 incorporates a battery compartment that holds up to two standardEOT Nickel Cadmium (NiCad) rechargeable batteries or one EOT Lead Acid type rechargeablebattery, depending on the configuration ordered. Replacement of the batteries does not require theremoval of the Model 6695 SBU from the train, or the use of any tools.

The batteries in the Model 6695 SBU have sufficient capacity to ensure lengthy operational lifebetween battery charges. The actual life expectancy is dependent on the number and type of batteriesused and the type of usage that is encountered. The batteries can power the Model 6695 SBU for morethan 72 hours at -40�C.

1.2.2.8 Antenna

The antenna is located at the top of the Model 6695 SBU and is made of a material which exhibitshigh-impact strength to below -40� C.

1.2.2.9 Brake Pipe Hose Retention Chain or Steel Cable

The SBU incorporates either a steel chain or plastic coated steel cable to provide support and removetension from the air hose.


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1.2.2.10 RS-232 Port

The RS-232 Port is a standard 9-pin, “D” connector located at the top of the battery compartment. Thisport allows a technician to connect a PC for diagnostics, testing and recalibration purposes.

1.2.2.11 Brake Solenoid

The Brake Solenoid is located inside the unit on the brake line manifold. When an emergency brakeapplication is requested by the Cab Unit, the End Unit opens this small solenoid operated pilot valvewhich triggers the exhaust valve (and the gladhand) to open, venting the brake line.

1.2.2.12 Motion Sensor

The motion sensor generates velocity and vibration signals, which the microprocessor interprets todetermine the state of motion and the direction of the last car.

1.2.2.13 Transceiver

The Model 6695 SBU contains a transceiver that transmits and receives communication between theEnd Unit and the Cab Unit. It provides enhanced frequency stability in the railroad environment. Thistransceiver is smaller and lighter than previous models.

1.2.2.14 Pressure Sensor

The Pressure Sensor measures the brake line pressure. It can measure pressures between 0 and 150psig (pounds per square inch, gauge), can withstand pressure up to 450 psig without damage andoperates in a temperature range from -40�C to +70�C. The Dual Pressure type SBU incorporates anadditional pressure sensor.

1.2.2.15 Temperature Sensor

An internal temperature sensor, located on the microcontroller board, allows the microprocessor todetermine the ambient temperature of the End Unit. On SBUs using NiCad type batteries, thetemperature sensor is used to correctly estimate the remaining charge on each battery.

1.2.2.16 Microcontroller Board

The Microcontroller board is an internal component of the End Unit. It is the longer of the two printedcircuit boards in the electronic cage. The Microcontroller board manages all timing and controlfunctions of the End Unit, including the communication functions.


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1.3 SPECIFICATIONS

Dimensions (with antenna) H = 31-1/2”, W = 9-1/2”, D = 5”

Weight: Approx. 30 lb. (with 1 NiCad battery)

RF: End Unit transmit frequency: 457.9375MHzEnd Unit receive frequency: 452.9375MHz

Power output: 2W (typ.) or customer spec.

Brake Line Pressure: Nominal operating range: up to 125 psig (Measurable)Maximum: 450 psig (Without Damage)

PC Interface: 9-pin D-Connector, IBM-compatible, RS-232

Marker Light: 1.0 second flash rate, FRA-compliant luminosity

Temperature Range: -40�C to +70�C

Humidity: 95% noncondensing at 40� C, 96 hour exposure


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1.4 FUNCTIONAL BLOCK DIAGRAM

The following a functional block diagram of a typical End Unit.

Actuate

ParameterEEPROM

Key XMTR

Sleep

CPU

InternalRAM

InternalA/D

Converter

InternalUART

+ 5 VDC

Marker Light

E. BrakeSolenoid Actuate

Test Battery

+12VDC

Lap-topfor Diagnostics

8888 LEDDisplay

Light Acknowledge

TiltSwitch

TransceiverCarrier Detect

4 bitD/A

4

TransmitAudio

ReceiveAudio

SystemEPROM

PressureSensor

AmbientLight Sensor

Regulator

velocity

vibration

TestSwitch

SignalConditioning

Circuitry

Marker Light Enable

E. BrakeCircuitry

SignalConditioning

Circuitry

MotionSensor

PressureSwitch

Diagnostics and CalibrationInformation

Figure 1-3. End Unit Functional Block Diagram

Section II INSTALLATION

SM 6496 4/96 2-1

2.1 INTRODUCTION

When installing the Model 6695 SBU, follow your railroad’s standard operating procedures.

2.2 BATTERY INSTALLATION

Installation or replacement of either the NiCad or Lead Acid type batteries does not require the removalof the Model 6695 SBU from the train, or the use of any tools.

2.2.1 NiCad Battery Installation

The SBU version supporting NiCad type batteries contains a battery compartment that holds up to two(2) NiCad rechargeable batteries. You can configure the unit for 1 or 2 batteries and allocate thepower to 1) the light only, 2) to the telemetry features only or 3) to both the light and telemetry features.To install and configure the batteries, follow the procedure below:

1. Release the two retaining latches on the battery compartment door.

2. Open the battery compartment door.

3. Loosen and remove the captive retaining nuts securing batteries to the posts.

4. Align hole in battery with battery post and snap battery onto circuit board. (The battery isdesigned to fit only when placed in the correct position.)

5. Replace retaining nut and hand-tighten to hold the battery in place.

CAUTION

The captive retaining nuts must be securely attached to each battery posteven if a battery is not present, to prevent potential damage to internalcomponents. The top of the nut must not extend above the top of the post.

6. Repeat steps 3-5 if using a second battery.

7. Close and secure the battery compartment door with the retaining latches.

NOTE

Remove the fuse cover on the circuit board before replacing fuses, changing thebattery configuration, battery sharing, or before installing the two batteries. Setthe jumpers on the circuit boards in one of the following positions as defined inFigure 2-1.


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To indicate battery sharing:

Shared:set jumper J1 to pins 2 and 3

set jumper J2 to pins 2 and 3

Unshared:set jumper J1 to pins 1 and 2

set jumper J2 to pins 1 and 2

To indicate the number of batteries:

One: set jumper J3 to pins 2 and 3Two: set jumper J3 to pins 1 and 2

To indicate the battery type:

4 amp-hr.: set J4 to pins 1 and 2

FUSES

BATTERY JUMPERSSHARED

UNSHARED

J1 SHARED NO. OF BATT. CAPACITY

J2 J3 J4NO YES 2 1

ALL FUSES2 AMP 3AG

F3 F2 F1

RADIO

LIGHT

UNION SWITCH AND SIGNAL

P/N M246XXX01

PROCESSOR

123

*4AMJ11 2 3

.....

Figure 2-1. Jumper Configuration for Batteries

Typical PinArrangement


SM 6496 4/96 2-3

NOTE

Batteries from previous End Unit models may be used in the Model 6695 SBU.

The Model 6695 SBU consumes less power to minimize battery-replacement cycles. To check thecondition of the battery, refer to Section 2.4, Unit Testing.

2.2.2 Lead Acid Battery Installation

The SBU version supporting the Lead Acid type battery contains a battery compartment that holds oneLead Acid rechargeable battery.

The SBU Battery Interface Board is factory configured to allocate power to both the Marker Light andthe Telemetry circuitry. To install the battery, slide it into the compartment so that it mates with theinternal power connector and secure it using the two latches on each side of the SBU.

The Model 6695 SBU is designed to consume small amounts of power in order to reduce battery-replacement cycles. To check the condition of the battery, refer to Section 2.4, Unit Testing.

2.3 UNIT MOUNTING AND ENVIRONMENT

The Model 6695 SBU clamps to the coupler of the last train car. The unit’s brake line sensing hoseattaches to the brake line by way of its attached gladhand as shown in Figure 2-2. For the DualPressure type SBU, attach the second gladhand to the second air source being monitored.

To prepare for End Unit installation, close the exhaust valve on the train’s last car. To install the Model6695 SBU, perform the following steps:

1. Place the gripping jaws of the Model 6695 SBU into the “guide arm” holes on the coupler ofthe train’s last car.

2. Tighten the clamp or jaws by turning the “key” or “crank” handle clockwise on the grippingjaws. After the handle is tightened, align the handle with the battery door retaining latch. Apadlock may be used to prevent the Model 6695 SBU and its battery from theft.

3. Connect the Model 6695 SBU’s exhaust valve to the gladhand of the last car and slowlyopen the angle cock. For the Dual Pressure type SBU, attach the second gladhand to thesecond air source being monitored.

NOTE

Some railroads choose not to use a padlock. If a padlock is not used, it isreommended that the “key” type handle be secured to the battery doorlocking lever with a “tiewrap”, “dog leash” latch or metal clip to preventthe clamp from loosening during transit.


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Coupler Side Track Side

Antenna

Test Push-button

Gripping Jaws

Exhaust Valve andGladhand

Emergency BrakePilot Valve

(cut-away view)

Exhaust Port

Coupler Clamp,unlocked

Coupler Clamp,locked

LED Display82481

AEI TagHolder

Figure 2-2. Typical Unit Mounting

The End Unit is powered up anytime that the brake pressure is above ten (10) psig. To minimize thebattery requirements whenever pressure drops and remains below five (5) psig for five (5) minutes, theEnd Unit will go into a “powered down” state. The Marker Light, if applicable, will remain operational aslong as the unit is not tilted or batteries removed.

2.4 UNIT TESTING

After installing the Model 6695 SBU, test the unit to ensure it is operational. When the test button ispressed and held, the display shows the following functions in sequence. The operation selected isdetermined by the function displayed when the button is released.

� PRESSURE� ARM� TEST� PHOTOCELL


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PRESSURE

1. Press the test button until the display reads “PRESSURE” and release the testbutton.

� The display will read:

“P###” (where # # # = brake pressure in psig)

for thirty (30) seconds and then go dark. To further conserve battery capacity, leadingzeros are suppressed in the display (e.x., “P 85”).

TEST

Pressing the test button on the End Unit until it displays “TEST” causes it to run through a self-testroutine and send a status radio report to the Cab Unit. The brake pressure, battery condition, the unitmodel number and the software version number are all shown in sequence on the display in the side ofthe unit.

1. Press the test button until the display reads “TEST”, then release the test button. TheMarker Light will flash for a configured number of seconds, the telemetry system will run aself-test, and the following information will be displayed:

� The customer identification string, or ‘US&S’ if nothing else is configured

� The software version number (e.x., “REV9”)

� The battery condition depending on the type of battery as follows:

(A) For the NiCad Battery type SBU, one of the following displays:

“OK# # ” Battery is Good, More than 39% of timed charge remaining.

(where # # indicates the estimated percentage of battery life remaining)

“LO# # ” Low - 39% to 12% of timed charge remaining (where ## indicates the estimated percentage of battery life remaining)

“WEAK” Weak - Less than 12% of timed charge remaining

“REPLACE” Replace - 0% of timed charge remaining


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(B) For the Lead Acid Battery type SBU, one of the following displays:

“GOOD” Battery is good. Voltage is approx. greater than 11.9 volts.

“WEAK” Battery is weak. Voltage is approx. between 11.9 and 10.7 volts.

“REPLACE” Battery needs replacement. Voltage is approx. between 10.6 and 10.0 volts.

“ABORT” Battery is non-usable. Voltage is less than approx. 9.9 volts.

� The results of self-test, including the emergency brake valve circuitry

� The brake line pressure as described in (1) above.

During the TEST sequence above, the Marker Light begins a self-test by flashing a configured amountof time.

2. When the test button is released, a status report is transmitted to the Cab Unit.

3. If the test button is pressed a second time before the self-test and the subsequent displaysequence is complete, the self-test process will restart immediately.

4. If the unit is in a "power down" condition when the test button is pressed (due to "zero"brake pressure) the unit goes into a "power up" state and runs the above tests. If brake linepressure remains below five (5) psig, the unit "powers down" after five (5) minutes toreduce power requirements.

5. A user-configurable option is an extended pressure display. After running the self-test, thedisplay will revert to showing the brake pressure:

"P # # # " (leading zeros suppressed)

The display will either remain visible (on for three (3) seconds, off for five (5) seconds) fortwo (2) hours, until the last car begins to move or the End Unit powers down, whichevercomes first.

NOTE

Due to the high current demand of the LED display, the extended pressure displayoption will reduce the life of the batteries per charge.


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PHOTOCELL

1. Press and hold the external test button until the word “PHOTOCELL” appears. The unitdisplays “PRESSURE”, “ARM”, and “TEST” before indicating “PHOTOCELL”. The displaywill become dark for the operator to check the photocell light sensor for proper operation.

2. If the ambient light level is relatively high due to bright lights or sunlight, cover the lightsensor located inside the display window to ensure that the Marker Light begins to flash.Uncovering the sensor should cause the Marker Light to stop flashing.

3. If the ambient light level is low, the Marker Light should already be flashing. To test a sensor in this condition, shine a light on the display window. When the light is removed, theMarker Light should begin flashing when sufficient light hits the photocell.

2.4.1 Diagnostics

A dedicated serial port, located at the top of the battery compartment, is provided so that a standardlap-top computer can be used for diagnostics and system configuration. The software package on thelap-top permits the customer to:

� Run internal diagnostics� View system parameters and variables� View and modify the End Unit ID number� Check and correct brake pressure calibration (if required)

The operation of the Diagnostic Unit Software and examples are described in Section 3.2.2.

2.5 UNIT INITIALIZING and ARMING

Each Model 6695 SBU has a unique ID number so every End Unit/Cab Unit pair can operate with aminimum of interference from similar units on nearby trains. The ID number is used to identifymessages sent to and received from its assigned Cab Unit. The Cab Unit must be initialized with the IDnumber of the Model 6695 SBU. One-way operation allows rear-to-front communication; two-wayoperation allows both rear-to-front and front-to-rear communication. One-way and Two-way operationare selected using the Diagnostic Unit Software.

2.5.1 One-way Operation and Initializing

When the End Unit is used in one-way service or sense-only operation, the Model 6695 SBU monitorsand sends information about the brake line pressure, state of motion of the last car and the status ofthe Marker Light to the one-way Cab Unit. To initialize the End Unit for one-way operation, it onlyneeds to have a usable battery installed and be connected to a pressurized brake line. To receivemessages from the Model 6695 SBU, the Cab Unit must be set to accept the unique ID code of theinstalled SBU.

When the brake pressure measured by the End Unit exceeds ten (10) psig, the End Unit goes to apower up condition, runs a self-test and begins normal status update reports.


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2.5.2 Two-way Operation and Arming

In two-way operation, or Sense and Brake operation, the Model 6695 SBU monitors and sendsinformation about the brake line pressure, state of motion of the last car, and the status of the MarkerLight from rear to front. The SBU is also equipped to allow for emergency brake applications from therear.

To minimize the chance of an unauthorized emergency brake application in the two-way mode, it isnecessary to “ARM” the Cab Unit to the End Unit. This prevents unauthorized external devices orpeople from activating the emergency brake function. It is not sufficient to permit the Cab Unit toinitiate the arming process because that opens the possibility for arming from unauthorized Cab Units.Some railroads may not require the security provided by the arming process. In such cases, the CabUnit can be configured to be armed at all times.

To “ARM” a Model 6695 SBU and its Cab Unit, follow these steps:

1. The locomotive operator enters the correct ID code into the Cab Unit so that it is in a “readyto arm” state.

The operator at the rear of the train presses the TEST button on the End Unit. When thebutton is released, a “REQUEST TO ARM” signal is sent by the End Unit.

2. When the Cab Unit receives the "REQUEST TO ARM" message from the End Unit, thelocomotive operator is prompted to respond. The locomotive operator has five (5) secondsto initiate a "COMMAND TO ARM" message by initiating a manual communications test (asdefined by the operations guide for the particular model of the Cab Unit in use).

3. If the End Unit receives the "COMMAND TO ARM" message within six (6) seconds of itsinitial arming message, it responds with an "ARMING CONFIRMATION" message (anormal status report complete with pressure reading, with the "CONFIRMATION BIT" set).The End Unit display will read “OK”.

4. When the Cab Unit receives the "ARMING CONFIRMATION" message, the armingprocess is a success. The locomotive operator knows immediately whether the armingprocess was successful because it is indicated on the Cab Unit.

NOTE

The Cab Unit is now authorized to execute an emergency brake command, if required.The locomotive operator should inform the End Unit operator by voice radio that thearming was successful. Railroad operating rules often require an exhaust valve teston the last car.

5. If a "COMMAND TO ARM" message is not received within six (6) seconds after the"REQUEST TO ARM" message is transmitted, the arming process fails and must berepeated before normal operation can begin.

6. If the Cab Unit does not receive an "ARMING CONFIGURATION" message within one (1)second of sending the "COMMAND TO ARM" message, the arming process fails and mustbe repeated before normal operation can begin.


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NOTE

The Cab Unit will indicate that the arming process has failed. The locomotiveoperator should inform the End Unit operator by voice radio that the armingprocess failed.

7. If the ID code entered into the Cab Unit does not match the "authorized" ID, (i.e. the one theCab Unit is armed to), the Cab Unit can receive status reports from the selected End Unitbut is prevented from sending emergency brake applications commands. Requests forstatus updates will be honored, but an alarm will sound.

2.5.3 Automatic One-Way/Two-Way SBU Operation

This feature is useful for railroads operating with a mixture of One-Way and Two-Way End-of-Trainequipment. This feature, when enabled using the Diagnostic Unit Software, causes the SBU toautomatically switch its communications protocol between One-Way (G) and Two-Way (J), to becompatible with the type of Cab Unit it detects is installed in the locomotive. If the SBU receives amessage from the Cab Unit, it determines it must use the Two-Way (J) protocol. On the other hand, ifthe SBU does not receive any messages from the Cab Unit during a 17 minute time period, it switchesto a One-Way (G) protocol. The 17 minute time period is based on the Cab Unit’s built-in automaticcommunications test function.

NOTE

During the time period that the SBU is determining its mode of operation (1-Wayor 2-Way), the Cab Unit may indicate a Valve Failure if it is a 2-Way Cab Unit orundetermined motion indications if it is a 1-Way Cab Unit. As soon as the SBUdetermines the correct mode of operation, it will automatically switch protocoland transmit a message to the Cab Unit to restore the proper indications.

This feature is enabled by using the Diagnostic Unit Software “Configuration Items” menu (Refer toSection 3.2.3 for information on Diagnostic Software screens). Select the item entitled "EnableAutomatic 1-Way/2-Way (G/J) Communications" and set the value to ON.

2.5.4 SBU LED Pressure Display Enable on Reception of Cab Message

This feature, when enabled using the Diagnostic Unit Software, causes the SBU to display the brakepipe pressure on its LED display whenever it receives a message from the Cab Unit and is in aSTOPPED state. The user performs this function by pressing the COMM TEST button on the CabUnit. When the SBU state is in motion, this display is suppressed.

This is a useful feature which provides a means for a person at the rear of the train to view thepressure being measured by the SBU without having to step on the track to press the SBU TESTbutton. The duration of the display ON time is configurable as described below.

This feature is enabled by using the Diagnostic Unit Software “Configuration Items” menu menu (Referto Section 3.2.3 for information on Diagnostic Software screens). Select the item entitled "EnableReceived Messages to Cause Pressure Display" and set the value to ON.


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The duration of the SBU pressure display ON time is configurable using the Diagnostics Unit Software“Configuration Items” menu. Select the item entitled "Set Brief Pressure Display Duration". This willchange the duration of the pressure display whether it is initiated by a Cab Unit message or by a pressof the SBU TEST button.

2.5.5 User Definable Password Protection

This feature allows the user to enter a custom password to permit access to the “Customer String”stored in the SBU’s non-volatile RAM (NOVRAM). User’s typically set the Customer String torepresent their railroad; for example “ABC Rail Co” or “ABCR”. This string is scrolled across theSBU’s LED display each time the unit is powered-up. This provides a measure of security by allowingthe user to identify that a specific SBU is owned, or not owned, by their railroad.

NOTE

The default password is set to “US&S” unless otherwise specified by thecustomer. Once changed, it is the responsibility of the railroad to remember thenew password setting.

The SBU Diagnostic Unit Software displays a “Password Protected Items” menu (Refer to Section3.2.3 for information on Diagnostic Software screens). The user can use this menu to change theCustomer String or enter a new password as follows:

The first item in the “Password Protected Items” menu is "Enter Password". This password must becorrectly entered before the other two (2) menu items can be accessed. The default password is“US&S”.

Once the correct password has been entered, the user can perform the following two (2) functions:

1. Enter or change the Customer String using the “Set Customer String (up to 31 characters)”menu.

2. Change the existing password using the “Change Password (up to 9 characters)” menu.

NOTE

As with all of the Diagnostic Unit Software items, the user must exit and terminate the SBUdiagnostic mode by unplugging the communications cable and then either pressing the SBUTEST button or powering down the unit by removing the batteries.

2.5.6 Allow Marker Light to be Manually Enabled

Some railroads use the End-Of-Train device to mark a train that has set out on a siding at night. Thisoptional mode allows the operator/installer to set the Marker Light to flash when it is dark, even with noair pressure applied.

This feature is enabled by using the Diagnostic Unit Software “Configuration Items” menu (Refer toSection 3.2.3 for information on Diagnostic Software screens). Select the item entitled "Allow MarkerLight to be Manually Enabled” and set the value to ON.


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Once enabled, pressing the external TEST button will cause the Marker Light to continue to flash whenit is dark, even with no air pressure applied. Tilting the End Unit will turn off the Marker Light.

2.6 AEI TAG INSTALLATION (Optional)

The model 6695 is equipped with a tamper resistant plastic holder for an Automatic EquipmentIdentification (AEI) tag. Refer to Figure 2-3 and the following procedure to install the AEI tag.

1. Open the battery compartment door and remove the batteries. If only one battery is used,disconnect the battery retaining nut on both posts.

2. Remove the twelve (12) screws that attach the rear cover to the EOT unit. Lift off the cover.

CAUTION

When handling the electronic assembly, follow proper ElectroStatic Discharge(ESD) procedures to protect the electronic module. If there are any questionsconcerning proper procedures, consult Union Switch & Signal’s CustomerService Engineering Group.

3. Removal of the Electronic Assembly:

a. Carefully disconnect the antenna cable from the radio assembly by turning the cableconnector counterclockwise approximately 1/4 turn.

b. Disconnect the four (4) cable connectors from the electronic module. Remove theseven (7) screws holding the electronic assembly to the unit housing. This will allowyou to remove the electronic assembly.

4. Remove the six (6) screws and rubber washers that attach the plastic AEI tag holder to theunit.

5. Place the AEI tag in the holder and ensure proper orientation of the tag.

6. To replace the AEI tag:

a. Reinstall the AEI tag holder by replacing the six (6) screws and rubber washers. It isrecommended that you apply Loctite 242 to the screws prior to their installation. Screwsshould be tightened to five (5) inch pounds to properly engage the rubber washers.

WARNING

Overtightening the screws on the AEI tag holder may damage the rubber washers.

7. Replacement of the Electronic Module:

a. Set the electronic module in the unit so that the controller board (N451923-1901) isseated in the casting to align the LED display with the window.

b. To install the seven (7) screws, it is recommended you use Loctite 242 prior toinstallation and tighten to eight (8) inch pounds.


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c. Replace the cable connectors. These connectors are keyed so that the connectors canonly be inserted into the proper receptacle on the electronic module.

NOTE

Do not overtighten antenna cable connector.

d. Connect the antenna cable connector to the radio assembly by turning clockwise 1/4turn.

NOTE

When replacing the cover, ensure that the male connector on the reardoor is properly aligned with the female receptacle on the electronicmodule.

e. Replace the twelve (12) screws on the rear cover. Apply Loctite 242 on each screwprior to installation. Each screw should be tightened to forty-six (46) inch pounds.

f. Replace the batteries, ensuring both battery retaining nuts are attached to the post andsecure the battery compartment door.

8. The unit is ready for operation.

Electronics Assembly

RemovableRear Panel

AEI Tag

Metal ID Tag

AEI TagHolder

Figure 2-3. AEI Tag Installation

Section III OPERATION

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3.1 GENERAL OPERATION

The Model 6695 SBU monitors and reports on the brake line pressure measured at the end of thetrain, motion status of the last train car and the state of the Marker Light. It also allows the locomotiveoperator to vent the emergency brake line from the rear of the train.

A scan of all inputs to the End Unit is made once per second, except for the radio receiver output whichis scanned approximately three (3) times per second. The End Unit only transmits changes in motion,battery condition, or rapid changes in brake pressure to the Cab Unit. Transmitting messages morefrequently would consume too much power and create unnecessary message traffic, which wouldinterfere with other units.

During its “steady state”, the Model 6695 SBU sends status reports on a semi-random schedulebetween fifty-five (55) and sixty-five (65) seconds. This random schedule allows transmitters to “talkaround each other” instead of “talking over each other” when several trains are in close proximity.

Since many trains can exist close to one another, each End Unit/Cab Unit pair must share a unique IDcode. Therefore, all messages received by either unit can be identified as coming from its “assigned”unit. For the End Unit, this 5-digit number is a unique identifier stored in the parameter storageEPROM of the End Unit during system fabrication. End-of-Train ID number allocation is administeredby the AAR clearinghouse.

3.1.1 Unit Power Up

The Model 6695 SBU has no power switch instead, it is activated when the following conditions occur:

1. The brake pressure goes from essentially “zero” (i.e., less than five (5) psig) to more thanten (10) psi.

or

2. The external test button is pressed and held until the display reads “TEST”, regardless ofbrake pressure.

In either case, the Model 6695 SBU goes to a “power up” condition, runs a self-test and beginssending normal status update reports.

3.1.2 Unit Power Down

1. If the brake pressure drops below five (5) psig for more than five (5) minutes, the Model6695 SBU transmits a final message indicating that the shut down is due to low pressureand goes to a “power down” condition.

2. The End Unit will remain powered up for five (5) minutes after pressure is removed.When the SBU is placed in a truck, the Marker Light could turn and stay on depending onthe light levels. To conserve battery power, the Marker Light is designed to turn off whenthe unit is placed on its side.


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3.1.3 Brake Pressure Monitoring

The main function of the Model 6695 SBU is to monitor and report the brake line pressure at the end ofthe train. The pressure is measured once per second. Although changes in other monitored inputsare transmitted immediately, brake pressure changes are reported to the front of the train as follows:

1. If the brake pressure changes by more than five (5) psig (either up or down) two (2)seconds after the last transmission, a status update report is sent immediately.

2. If the brake pressure changes by more than two (2) psig but less than five (5) psig (eitherup or down) five (5) seconds after the last transmission, a status update report is sentimmediately to the Cab Unit.

3. If the brake pressure changes by less than two (2) psig (either up or down) since the lasttransmission, a pseudo-randomized interval timer is set to transmit an update messagebetween fifty-five (55) to sixty-five (65) seconds. This pseudo-random “back-off and retry”time reduces the chance that two (2) transmitters can repeatedly block each other byrepeatedly transmitting at the same time.

4. If the actual brake pressure exceeds 125 psig, the value is limited to 125 psig.

3.1.4 Motion and Direction Sensor

The motion detector in the End Unit is checked every second.

1. When motion is monitored and the last train car begins to move, the End Unit sends astatus report indicating the motion of the last car. As long as the last car continues tomove, all subsequent status reports will indicate ‘MOVING’.

2. When motion is monitored and the last train car comes to a stop, the End Unit sends astatus report indicating no motion of the last car. As long as the last car remains at rest, allsubsequent status reports will indicate ‘STOPPED’.

3. When both motion and direction are monitored, and the last car is moving, the Model 6695SBU sends a status report indicating the “FORWARD” or “REVERSE” motion of the lastcar. After approximately 20 seconds, “FORWARD” or “REVERSE” is replaced with“MOVING”. As long as the last car continues to move in the same direction, all subsequentstatus reports will indicate ’MOVING’.

3.1.5 Battery Monitoring

1. If the operator at the end of the train presses and holds the external test button, and thenreleases it while the display reads “TEST”, a test sequence starts and displays informationincluding the state of the battery. The battery state is computed by the CPU based on thebattery’s output voltage, system on-time and ambient temperature and is displayed asdescribed in Section 2.4.

2. If the telemetry battery drops below the minimum operational voltage, a final shut-downmessage is transmitted. This message repeats once per minute for three (3) minutes toimprove the chance that the Cab Unit receives the final message. Then the Model 6695shuts down.


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3.2 EMERGENCY OPERATION

3.2.1 Emergency Brake Application (Standard Operation)

The emergency air release brake valve located in the End Unit is an emergency braking device, NOT abraking performance improvement device.

1. When the End Unit receives the emergency brake command, it begins (within one (1)second) an emergency brake command cycle and holds the emergency brake pilot valveopen for 45 seconds (default). The End Unit immediately sends an acknowledgmentmessage to the Cab Unit to indicate that the pilot valve has opened.

2. After the 45 seconds have passed, the End Unit releases the brakes by re-closing theemergency brake pilot valve. The End Unit sends a status update report indicating that ithas again closed the pilot valve. The brake line can be repressurized.

3. If the operator at the rear of the train presses the external test switch on the End Unit whilethe emergency brake pilot valve is still open, the End Unit truncates the emergency brakecycle and prepares for releasing of the brakes by re-closing the pilot valve. The End Unitsends a status update report indicating that it has again closed the pilot valve.

3.2.2 Emergency Brake Application (Manual Reset)

Some railroads require that the SBU TEST button be manually pressed to re-close the pilot valve afteran Emergency Brake Application. In this case, the unit will keep the pilot valve open indefinately untilan operator walks to the rear of the train and presses the TEST button. The SBU can be configured tooperate in this mode by using the Diagnostic Unit Software Configuration Items Menu “Set Brake ValveOpen Duration” and entering a value of zero seconds.


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3.2.3 Diagnostic Unit Software

The Diagnostic Unit Software is a program that runs from your PC, which allows you to configure theEnd Unit, run diagnostics on it and view its internal state. The Diagnostic Unit Software communicateswith the End Unit via a serial link cable plugged into the 9-pin D-connector located at the top of thebattery compartment. The software can be ordered by part number N4512321264 (3.5” disk) orN4512321265 (5.25” disk). When you execute the program (diagunit.exe), it displays the followingscreen:

The program name and version appear at the top of the screen. The box at the bottom of the screenprompts the user for input. The last line shows applicable function keys.

3.2.3.1 Keys

By default, the program uses PC serial port COM1 to communicate with the End Unit. If that port isunavailable, press < F2> to use COM2. To return to COM1, press < F1>.

You can quit the program at any time by pressing the F4 key. The following prompt will appear: “Areyou sure? [Y/N]”. Press “Y” to end the program, or “N” to continue.

3.2.3.2 Connecting the End Unit

The Diagnostic Unit communicates with the End Unit via a straight-through (not a null modem cable)serial link cable plugged into the 9-pin D-connector located at the top of the battery compartment. Onthe PC, use the COM port which you selected at the startup screen of the Diagnostic Unit program.

When the End Unit and Diagnostic Unit are connected, initiate communications by pressing theexternal test button on the End Unit. The Diagnostic Unit should then display the main diagnosticmenu.


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3.2.3.3 Main Menu

When the End Unit is operating in diagnostic mode, the first screen displayed on the PC is the MainMenu.

To select one of the submenus displayed, type selected item number and press <Enter>.


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3.2.3.4 Diagnostic Items Menu

The Diagnostic Items Menu displays selections which may display information about the End Unit orperform a diagnostic test:

To select an item from this menu, enter a menu item number and press <Enter>. To return to the MainMenu, press <Esc>.If the item selected needs only a single line to display its result, the text will appeardirectly above the prompt box. The above example shows the result of selecting item 1, “Show ModelAnd Version”.


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3.2.3.5 System Information

This screen is the result of selecting “Show System Information” from the Diagnostic Items Menu. Itshows the current state of various internal sensors. To update or repeat this screen, press <F1>. Toreturn to the Diagnostic Items Menu, press<Esc>.

3.2.3.6 Configuration Items Menu

This screen is the Configuration Items menu, selected from the Main Menu. To select an item from thismenu, type a number and press <Enter>. To return to the Main Menu, press <Esc>.

Each of these items are a value which can be changed interactively. See the following example.


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3.2.3.7 Set Id Code

This screen shows the Set Id Code item selected from the Configuration Items menu. It shows thecurrent value and prompts for a new value to be entered. When a new value is entered, the currentvalue displayed changes to show the new value. To return to the Configuration Items menupress<Esc>.


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3.2.3.8 Set Message Protocol Type

This screen shows the “Set Message Protocol Type” item selected from the Configuration Items menu.It shows the current value both in symbol and numeric form, and shows each of the possible valueswhich can be entered. To change the value, enter the number of one of the possible values listed andpress <Enter>; the current value will then show the new value. To return to the Configuration Itemsmenu, press <Esc>.

Setting the message protocol type configures the End Unit to send the selected message format to theCab Unit. When you change from one type to another, you must ensure that the End Unit is alsoconfigured in one-way or two-way mode, whichever is compatible with the selected message type. Toconfigure the unit for one-way or two-way mode, return to the Configuration Items menu (by pressing<Esc>) and select “Set two-way Mode”.


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3.2.3.9 Pressure Sensor Calibration Menu

This screen is displayed when “Pressure Sensor Calibration” is selected from the Main Menu.

To calibrate the pressure sensor follow the instructions and set the air pressure attached to the EndUnit to zero; press <Enter> when this is done.

The next screen will prompt you to set the air pressure to 100 psig; set the air pressure attached to theEnd Unit to 100 psig and press <Enter> when this is done.

The next screen will confirm that the pressure sensor is now calibrated. To return to the MainMenu, press <Esc>


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3.2.3.10 Set Password Protection Screen

This screen is displayed when “Password Protected Items” is selected from the Main Menu.

The user can use this menu to change the Customer String or enter a new password. The defaultpassword is set to “US&S”. Once changed, it is the responsibility of the railroad to remember the newpassword setting.

The first item in the “Password Protected Items” menu is "Enter Password". This password must becorrectly entered before the other two menu items can be accessed. The default password is “US&S”.

Once the correct password has been entered, the user can perform the following two functions:

1. Enter or change the Customer String using the “Set Customer String (up to 31 characters)”menu.

2. Change the existing password using the “Change Password (up to 9 characters)” menu.

To return to the Main Menu, press <Esc>.

Documents

END-OF-TRAIN SENSE AND BRAKE UNIT · END-OF-TRAIN SENSE AND BRAKE UNIT R An ANSALDO Affiliated Company Installation Operation. TABLE OF CONTENTS SM 6496 4/96 i I. INTRODUCTION.....1-1