Terry (Customer) asked a question.
I have a continues input, on all the time, How can I create a one time pulse to start a series of timers.
What I need is: when the power comes on I need the PLC to output 2 pulses to operate a relay to set a machine, it is connect to, into the proper operating mode. The input is on all the time power is applied. Is there a way to, inside the PLC turn this into a single short pulse to start the timers which will create the output pulses. Keep in mind the power is on all day only shut off at night. The next time this operation would take place is when the power is turned on the next day.
Thanks,
Terry
The system contact SC2, _1st_SCAN is; "ON for the First Scan only." One might use it to start an off delay timer?
Also by default C contacts are non-retentive and default to false, one could pick a C bit to use for a fresh start flag, if it is OFF, SET it ON and then do you other stuff. That will only happen once (until the power is cycled) since once it has been SET ON, checking if it is OFF will return false
A timer on an unconditional rung should begin to time when the PLC powers up ... I have not tested this with a Click, but have done it numerous times with A/B PLCs to delay an action on power up of the PLC. Just a timer all by itself and use its done bit to trigger the other timers as needed.