McQuay AGZ 035A, Инструкция по установке, эксплуатации и обслуживанию

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IOMM AGZ-3 AGZ 035A through 065A 83
Figure 31, MCB Power Supply Terminals
POWER FUSES
[BUSSMAN GDC-T2A]
PO
W
E
R
IN
[18-24 V
C
T]
AC AC G
ND G
N
D
AUX / OUT
4
3
2
1
9 8 7 6 5 4 3 2 1
Fuse F1
Fuse F2
Troubleshooting the Keypad/Display Interface
The Keypad/Display Interface is connected to the MCB via a ribbon cable and discrete wiring for the
back light. The MCB provides operating voltages, control signal outputs for the display, and input
conditioning for the keypad inputs.
Display is Hard to Read
The clarity of the LCD display can be affected by ambient temperature. Typically, less contrast will
result with cooler temperatures. If the display is difficult to read, adjust the contrast trim pot, which is
located on the back of the keypad/display assembly.
Back Light Not Lit
The Keypad/Display Interfaces supplied with the controller is equipped with a back light. If the light
does not come on, check for 5Vdc at terminal 9 on the IDC connector on the KDI and for 5 Vdc on
the CSC field wiring terminal strip.
Check for 5Vdc on the IDC connector on the To check for the 5Vdc on the IDC connector, pull back
the plug about one-eighth of an inch and place the test leads against the exposed pins. If there is no
voltage, check the wiring and the connections between the controller’s 5Vdc field wiring terminal
strip and the KDI. If the wiring is intact the MCB is probably defective.
Display is Blank or Garbled
If the MCB appears to be functioning properly and the display is completely blank or garbled,
perform the following procedure:
1. Try cycling power to the controller by opening and then closing circuit breaker CB1 (see note
below).
2. Try adjusting the contrast trim pot, which is located on the back of the keypad/display assembly.
If the contrast trim pot has no effect, it is likely that either the keypad/display or its ribbon cable
is defective.
3. After removing power from the controller, check the ribbon cable and connections between the
keypad/display and the MCB. Look for bent pins. Restore power after reconnecting the ribbon
cable.
4. Try swapping a known good ribbon cable and keypad/display. Swap these components separately
to isolate the problem. Remove power from the controller before disconnecting the suspect
component, and restore power after connecting the replacement component. If the problem
persists, it is likely that the MCB is defective.