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Technical support / Using PulsePeriod(ch)
« on: September 01, 2016, 08:24:57 PM »
I would appreciate some advice on the use of PulsePeriod(ch) instruction.
From what I understand, firstly, initiate the channel using the PMON instruction.
I assume this would be accomplished in a custom function and that this function can be called using the 1st.scan bit.
This function will contain the instruction PMON 1 only. (for example)
Then, in another custom function you would use dm[1] = PulsePeriod(1), then do what ever you have to do with dm[1].
From what I read, this mechanism is free running so, if for example, your ladder is doing an Analog to Digital conversion and ch1 transitions from low to high,
the A to D conversion will not be interrupted.
Then, when you call your Pulse Period Function, the last valid pulse period will be loaded into dm[1].
I simple need to know if my air conditioning condenser fan is running above a certain speed before engaging the compressor.
Is the attached example on the right track.
Thank you
Gavin
From what I understand, firstly, initiate the channel using the PMON instruction.
I assume this would be accomplished in a custom function and that this function can be called using the 1st.scan bit.
This function will contain the instruction PMON 1 only. (for example)
Then, in another custom function you would use dm[1] = PulsePeriod(1), then do what ever you have to do with dm[1].
From what I read, this mechanism is free running so, if for example, your ladder is doing an Analog to Digital conversion and ch1 transitions from low to high,
the A to D conversion will not be interrupted.
Then, when you call your Pulse Period Function, the last valid pulse period will be loaded into dm[1].
I simple need to know if my air conditioning condenser fan is running above a certain speed before engaging the compressor.
Is the attached example on the right track.
Thank you
Gavin