Kevin Wynne Posted April 21, 2020 Report Share Posted April 21, 2020 Hi, I need to connect several flow meters that output a low frequency pulsed signal. I can easily do this with the HSC ports but they are limited in number and the frequency I need doesn't warrant their use. How can I use the standard digital inputs to count the pulses sent from the flow meters? I plan to use a V120 to do this. Thanks Kevin Quote Link to comment Share on other sites More sharing options...
AlexUT Posted April 21, 2020 Report Share Posted April 21, 2020 To count pulses in Ladder code, input signal, either 0 or 1, should be detected during 3 or more scans. *Take a maximum scan time. B.R. Quote Link to comment Share on other sites More sharing options...
MVP 2022 Joe Tauser Posted April 21, 2020 MVP 2022 Report Share Posted April 21, 2020 1 hour ago, Kevin Wynne said: flow meters that output a low frequency pulsed signal Be a little more specific on this. I would step up to a V130 as it allows you to run a 1.25 ms interrupt routine. If you use Immediate Inputs in this routine and increment your pulse counters there you get a pseudo-HSC input on all your on-board inputs with a frequency response of 400 Hz. Joe T. Quote Link to comment Share on other sites More sharing options...
Kevin Wynne Posted April 21, 2020 Author Report Share Posted April 21, 2020 Hi, So I guess the question now becomes how do I set up the interrupt routine? Kevin Quote Link to comment Share on other sites More sharing options...
MVP 2022 Joe Tauser Posted April 21, 2020 MVP 2022 Report Share Posted April 21, 2020 Type "interrupt" into the search box in the Help and all the answers will be revealed.... If that doesn't work post your code here and we'll hack one in for you. Joe T. Quote Link to comment Share on other sites More sharing options...
Kevin Wynne Posted April 21, 2020 Author Report Share Posted April 21, 2020 Thanks Quote Link to comment Share on other sites More sharing options...
MVP 2022 Ausman Posted April 21, 2020 MVP 2022 Report Share Posted April 21, 2020 Kevin, in addition to what Joe has said re the actual frequency which is very relevant to whether the plc will handle things properly through normal inputs, have a look at this post and also the entire topic to get background. It might be exactly what you need. cheers, Aus Quote Link to comment Share on other sites More sharing options...
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