Manual 26166V1 MicroNet Simplex & MicroNet Plus
Woodward 45
4. Toggle the CPU’s RESET switch. The CPU’s red Fault and Watchdog LEDs should turn off, and the
green RUN LED should go on. At this time, the CPU is performing the self-diagnostic and boot-up
processes. When the CPU has completed its diagnostic tests, all red LEDs on the CPU module or I/O
modules should be off, and the control will begin running the application program.
5.1.3—Power Supply Troubleshooting
System diagnostic routines continuously monitor each main power supply for proper operation. If a fault
condition is detected, the fault is annunciated. If necessary, use the power supply’s front panel LEDs to
assist in diagnosing any related problems. If all supply LEDs are off (not illuminated), it is probable that
input power is not present, and verification should be made.
Power Supply LED Descriptions
OK LED—This green LED turns on to indicate that the power supply is operating and that no faults are
present.
INPUT FAULT LED—This red LED turns on to indicate that the input voltage is either above or below the
specified input range. If this LED is on, check the input voltage, and correct the problem. Long-term
operation with incorrect input voltages may permanently damage the power supply. Once the input
voltage is within the supply’s input specifications, this LED will turn off. Refer to the power supply input
specifications.
OVERTEMPERATURE LED—This red LED gives an early warning of a thermal shutdown. The LED
turns on to indicate that the internal power supply temperature has exceeded approximately 95 °C. If the
internal supply temperature rises to approximately 100 °C, the supply may shut down. Because of the
many variables involved (ambient temperature, load, thermal conductivity variations), there is no accurate
way of predicting the time between the indication of overtemperature (LED illuminated) and power supply
shutdown.
If this LED is turned on, verify that the fans in the power supply chassis are turning and free of dust and
other obstructions, and that the temperature around the power supply is less than 55 °C. If the power
supply is cooled down without delay, it can recover from this situation without shutting down. This LED
will turn off once the internal power supply heatsink temperature falls below approximately 90 °C.
POWER SUPPLY FAULT LED—This red LED turns on when one of the supply’s three power converters
has shut down or one or more of the supply levels is below internally specified levels. If this LED is on,
check for a short circuit on external devices connected to the control’s power supply. When the short
circuit has been removed, the supply will resume normal operation (Note that if the 24 V or 5 V outputs
are shorted, these power converters will be latched OFF and can only be cleared by removing the shorted
condition and removing the input power for 1 minute (or until the front panel LED’s extinguish)). If no short
circuit is found, reset the supply by removing input power for one minute. If the power supply is still not
functioning after input power has been restored, verify that the supply is properly seated to the
motherboard connector. If the supply is properly seated but is not working, then replace the supply.
Simplex Power Supply Checks
The following is a troubleshooting guide for checking areas which may present difficulties. If these checks
are made prior to contacting Woodward for technical assistance, system problems can be more quickly
and accurately assessed.
Is the input power within the range of the control’s power supply input?
Is the input power free of switching noise or transient spikes?
Is the power circuit dedicated to the governor only?
Are the control’s supplies indicating that they are OK?
Are the control’s supplies outputting the correct voltage?
Is the CPU Low Vcc LED ON?
To Next Page
Loading...
