Rockwell Automation 1746-HSCE2 Multi-Channel High Speed Counter Module - Manual (Page 87)

Publication 1746-UM002B-EN-P - August 2004
Start Up, Operation, Troubleshooting, and Debug Mode 5-5
The rate underflow bit is set when the rate value is less than the
minimum rate value.
When the module is in overflow condition, the programmed
maximum rate value is reported and ranges that include the value will
still be acted upon. Likewise, in underflow condition, the minimum
rate value is reported, and ranges including it are affected.
Counter Value Does Not Change
Check the LEDs associated with the Channel A and B inputs which
have pulses coming in. The A and B LEDs should flash whenever
pulses are being received by the 1746-HSCE2 module.
If the A and B LEDs do not flash, check the power to the input sensor
and the wiring from the sensor to the module.
If the A and B LEDs flash, make sure that the configuration of the
module is complete and counters are enabled.
Counter Value/Rate Value Goes in the Wrong Direction
If single-ended encoder inputs are used, swap channels A and B to
change the direction. If differential encoder inputs are used, swap
A(+) and A(-) wires.
If pulse and direction inputs are used, check the direction and input
type.
If using up and down pulses mode, make sure inputs A and B have
not been switched.
Output Does Not Turn On
Make sure the SLC processor is in run mode.
Check the output’s LED.
If the LED is illuminated, check the power supply and its connections
to the module. Also check the connections to the output device.
If the LED is not illuminated, make sure the SLC processor is in the
run mode, and that a module fault has not occurred. Check the output
status field of the input image to see if the module is trying to
energize the output. If not, make sure that the enable ranges byte and
the output OFF mask are set.
Check the fuse status bit.