
MEP 660 - Trouble shooting Manual
Doc No.: IM – 51
Rev.2.0
Print: October 2008
209
PARAMETER
DESCRIPTION
FAULT CODE
1202
FAULT MESSAGE P22 Auxiliary Contact Stuck Open. Run Auto/Manual Test
RESTRICTIONS
--
ALARM BELL
--
RESET LEVEL
Low, Manual
If the fault condition is still present when cleared manually, the fault
will be generated again.
FAULT
RECOVERY
Automatic when the P22 power contactor Aux. Contact closes.
PROBABLE
CAUSES
1. Defective Power contactor
2. Defective wiring.
3. Defective digital output card MLSD16 in slot No. 14.
4. Defective digital input card MDIP16 in slot No. 10
FAULT
ISOLATION
1. Set the display mode to ‘Manual Test for outputs’ under ‘Test Mode’
available in main menu. The display exhibits certain conditions to
be full filled. After that press Enter key to start testing of outputs.
Ensure control air pressure is 5 Kg./Sq.Cm.
2. Enter 4 against channel no. and then press Enter key to test P22
power contactor. Press 1 to energise the contactor and 0 to de-
energise the contactor.
3. Press 1 to energise the P22 power contactor.
4. If the contactor is not picking up. Check the voltage across the
operating coil of the magnet valve.
5. If the voltage is zero, check the voltage between Wire 13 at the coil
terminal and locomotive 4 wire.
A. If the voltage is zero, check the continuity of 13 wire connected
to the coil terminal.
B. If the voltage is more than 65V, check the voltage between
locomotive 13 wire and P22CL wire at the coil terminal.
C. If the voltage is zero, negative path is not getting completed
through MEP.
a) Check the slackness of the connector at MEP-660 control unit
for the cable ID: AY. If found slack tighten the connector.
b) Check the continuity of wire P22CL from the coil terminal to
the connector of cable ID: AY (pin – E). If necessary replace
the cable.
c) If still voltage is zero, the digital output card MLSD16 in slot
No. 14 might be defective. Replace the card and check once
again.
6. If the Voltage is more than 65V and still power contactor is not
picking up, then the power contactor or magnet valve or pneumatic
circuit is defective. Identify and replace the component/contactor.
7. Press 0 to de-energise the power contactor.
8. While you are toggling the power contactor, check the status of the
Green LED 7 and Yellow LED 7 on the digital input card MDIP16 in
slot 10.
9. With power contactor energized, Both the LEDs should glow.
10. If the Green LED is not glowing, check the voltage between wire 51
at the power contactor aux. Interlock and locomotive 4 wire.
A. If the voltage is zero, check the continuity of the wire Loop 51
connected to P22 power contactor interlock. Identify faulty