OR latch with a reset?

General
1

Hi,
I have a project where I want to measure the pressure drop across a filter bank supplied by 2 pumps.
I need either a function or group of nodes that trigger the pressure drop calculation flow 5 seconds after either of the pumps start running and continue until both pumps are running.
The pumps status are signaled from optocouplers continuously sending 0's or 1's
I believe this will work

  1. have two status messages sending 1 = on and 0 = off
  2. OR function from 2 inputs signals start after 5 sec delay
  3. start remains until both status is off, then is stop
    I can achieve parts of the requirement but it gets very messy when trying to stop
2

Sounds like you want an XOR gate. Perhaps this will work?

image
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3

@jbudd hey thanks so much, yes this looks good. I wasn't sure about the delay on the stop. The delay is to give the pump/'s time to get to pressure to eliminate the water hammer/pressure spikes on pressure up. The thought was to stop recording when the pumps stopped in case of any other issues and to ensure clean data. I looked at removing the delay on the stop but that incurs a stop, 5 seconds, start, 5 seconds Stop stop etc etc. I'll set it all up and see how i go. Many many thanks

4

You migth also want to look at the Boolean logic nodes - very comprehensive

Craig

5

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