Manual

21
Installation and Maintenance Manual
Chapter 5: Fault Check
Chapter 5: Fault Check
The Fault Check option provides an automatic in-process self-diagnostic mechanism to verify that all
PLS functions are operating properly.
The Fault Check option will detect and disable system operation in the event of any of the following
problems:
1. Disconnect or severed resolver cable.
2. Open or shorted resolver signals.
3. Resolver excitation failure.
4. Resolver-to-digital converter or associated electronic failure.
5. Microprocessor or 5 volt power supply failure.
Non-system-type faults, such as individual output failures, will not be sensed. It is recommended that
the Fault Check output be used as an operate enable type signal. Loss of this output should immedi-
ately stop the process which is being controlled.
The Fault Check input may be operated by an isolated contact, current sourcing, or current sinking
device 5V DC at 10mA.
A normally closed, momentary open contact button can be wired per Fig 11-2, Chapter 11: Wiring
Diagrams, to activate the Fault Check circuit, and it will provide a method of resetting the fault output
after a fault condition has been sensed.
To reset the Fault Check output after the fault condition has been cleared, the fault reset input must be
deactivated (open circuit) and then re-actuated. Cycling the fault reset input will cycle the fault check
relay to verity that the Fault Check output is operating properly.
NOTE: If the Fault Check inputs are not wired, the display will still show when there is a fault and the
outputs will be disabled, but it will not lock on the fault. However, if the fault check inputs are
wired as per Fig 11-2, Chapter 11: Wiring Diagrams, then upon seeing a fault, the fault check
relay will drop out and all outputs will shut off until the fault is fixed and the fault check input is
reset.