AMETEK 1995L Micro-Set PLS - Manual (Page 19)

15 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. Analog to digital converter or associated electronic failure.
2. 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 10-1, Fig. 10-2, OR
Fig. 10-3 (Chapter 10: 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 up per Fig. 10-1, Fig. 10-2 or Fig. 10-3 (Chapter 10: Wiring Diagrams), 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.