If you are using the AB ControlLogix platform and want a bit to cycle on and off at a consistent rate, you can address one of the bits of the register that represents the clock microseconds. (GSV WallClockTime) The register containing the microseconds is the 7th element in the array:
The scan time of the PLC will dictate how fast the register will update. I was running under 1ms and the periods longer than 8ms were measurable.
Reference the bit with the desired period you want to trigger off of:
