IM620-1
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1.
Try cycling power to the controller by opening and then closing circuit breaker CB1.
2.
Check the ribbon cable(s), power wiring from MAG to the AOX-4, field wiring connections from
the AOX-4 to the analog output device, and the power wiring from the external power supply to
the output device. Look for bent pins, cable on backwards, or miswires. Restore power after
reconnecting all cables and wires.
Note:
If the analog output signal supplied by the MAG is a voltage signal (0–5, 0–10 Vdc), the
external power supply ground must be grounded to the MicroTech Controller’s chassis ground.
3.
If the problem persists, try swapping a known good AOX-4, ribbon cable(s), analog output
device, or external power supply. Swap these components separately to isolate the problem.
Remove power from the controller and analog output device 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.
Troubleshooting Output Boards
Each output on the output board consists of a solid-state relay, an LED, 5-amp fuse, and an MOV
(metal oxide varistor).
Normally, when the MCB commands an output to energize, the solid-state relay contacts close and
the LED glows. The contacts of each solid-state relay are in series with a 5-amp fuse. These fuses
resemble small resistors and are located on the board adjacent to the relays they serve (see Figure 19).
The fuses are pressed into place. They can be removed with a needle nose pliers. The MOV, which is
located on the underside of the output board, protects the solid-state relay from high transient
voltages. MOVs are part of the output board and cannot be replaced.
Following are troubleshooting procedures for various symptoms of output board problems
Note:
It should be possible to determine whether a solid-state relay is defective by using these
procedures. However, if you need more information on troubleshooting them, refer to
“Troubleshooting Solid-State relays” below.
!
WARNING
Electric shock hazard. Can cause severe injury or death.
Even when power to the panel is off, solid-state relay socket terminals 1 and 2 on the output
board could be connected to high voltage (see Figure 19). Avoid them.
