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dumb question

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NovicePLC

Computer
Joined
Apr 5, 2009
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2
Location
US
Hello
First time poster looking for advice on a PLC program.

Goal
1. record time a sensor is on
2. delay signal for 3 seconds
3. send signal to motor and have it run for as long as the sensor did

Should I use a retentive time or use both on and off delays?

thank you!
 
There is no such thing as a dumb question. Now to answer your question, there are several ways to do what you want. One way is to use one on delay timer and one off delay timer, both set to three seconds. The on delay starts the motor, and the off delay stops it. This is probably the simplest way.
 
It seems to me you should have a timer with a long setpoint to measure the "Sensor ON Time".
On the transition from ON to OFF copy the "Sensor ON Time" elapsed time to the setpoint of the "Motor Run Timer".
Clear the "Sensor ON Timer" elapsed time.
Wait 3 seconds "Delay Timer" then run the motor until "Motor Run Timer" expires.
Hope this helps
Roy
 
Good start for me. Just getting my feet wet with this stuff. Many thanks.
 
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