Rockwell Automation 1746-HSCE2 Multi-Channel High Speed Counter Module - Manual (Page 129)

1 Publication 1746-UM002B-EN-P - August 2004
Appendix
D
Frequently Asked Questions
This appendix presents some of the more commonly asked questions
about application and operation of the Multi-channel High Speed
Counter Module. The following questions and answers do not cover
all possible questions, but are representative of the more common
ones.
Q: What happens when my processor faults?
A: All outputs will turn off. In a remote chassis, the status of the
outputs when the processor faults is dependent upon the last state
bit.
Q: What happens to my outputs if I place the processor in program mode?
A: All outputs turn off. The inputs remains active and the module
keeps counting. When the processor is returned to RUN mode, all
defaults are restored.
Q: What does it mean when the indicator for a particular input is on.
A: If the indicator is on, it means that input voltage is present. If the
indicator is off, the input is floating or has no voltage.
Q: What does it mean when an output indicator is on?
A: Since the output indicator is tied to the logic side of the module, it
means that the module has commanded the output on. It does not
necessarily mean that the output is on. The indicator illuminates
even when no connection is made to the outputs or to the output
supply. For an output to actually turn on, the output power supply
must be connected.
Q: What are the delay times for turning the outputs on and off?
A: The outputs turn on in < 10 µs, and turn off in < 100 µs. However,
overall throughput is between 300 µs and 1.5 ms. Throughput is
the delay time between the module receiving a pulse and the
updating of its real outputs and the SLC backplane.