User's Manual

SECTION II INSTALLATION
SM 7063 07/97 2-7
2.5.2 CDU Functional Check
Perform the following basic steps to verify that the CDU is functioning correctly:
Obtain a known operational End Unit. It may be operated within the locomotive without damage and no
pressurized air is necessary.
Power-up the CDU, observe it completes its power-on sequence, and then enter the ID code of the End
Unit into the CDU.
NOTE
If the CDU is configured to support the “Arming” security feature, it will prompt
the user to perform the Arming process as described in Section III. IT IS NOT
NECESSARY TO DO THIS IN ORDER TO PERFORM A FUNCTIONAL CHECK OF
THE CDU.
Press the external TEST button to activate the End Unit and cause it to transmit a message. Observe
the Brake Pressure Display on the CDU. With no air pressure applied to the End Unit, the pressure
reading should change from
“- - -”
to
“ 0”
psi. This will be accompanied by a Low Pressure Alarm
since the pressure is below the standard 45 psig threshold and is normal.
Press the
COMM ARM
key on the CDU to initiate an RF link check. Observe the CDU’s 32-character
LED Display briefly shows
“WAITING FOR REPLY”
, shortly followed by
“COMM TEST OK”
. This
confirms correct operation of the CDU’s RF transceiver and associated control circuits.
Note:
The rightmost decimal point in the Brake Pressure Display serves as an indicator to show that a
message has been received from the End Unit. It will briefly light each time a message is
received.
Verify the integrity of the Emergency Switch contacts by activating the switch and observing a
“SYSTEM IS NOT ARMED”
message on the Function Menu Display.
Perform a
LAMP TEST
to verify that all of the LED display segments light. This is done by
simultaneously pressing the
MENU UP
and
MENU DOWN
keys as marked on the front panel .
Observe that each of the CDU’s nine (9) Control Pushbuttons are illuminated (i.e., backlit).