How can I connect a Hall Effect Flow Sensor output to PLC?

[kdv1988]

Hello guys,

I am building a small prototype for a Coolant Dispensing System and need to measure the flow rate of water & chemical in the pipe in order to control the opening of valves downstream.

Since I am building a small pilot system, I can't really spend too much money and hence I intend to use those cheap Hall Effect Flow Sensors available online. Accuracy isn't important right now, but repeatability is!

So my question, how do I connect the Pulse Output of the Flow Sensor to the PLC?

https://gofile.io/?c=dt9oHh

- the sensor

 

[LionelHutz]

You connect it to a digital input that can count pulses, then set-up the PLC to count the pulses over a period of time.

 

[kdv1988]

But the sensor output is 5V.. Can the PLC read that?

 

[IRstuff]

Why not?

TTFN (ta ta for now)
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[thebard3]

A standard discrete PLC input module may not be able to discern the pulses at the frequency shown which I understand to be 98 pulses per liter/min of flow. It looks like a small meter so if your flow rate is 1 liter/min or something like that I'm sure it's okay.
Higher frequencies would typically require a high speed counter card. As far as the voltage is concerned, you need a DC input card rated for the operating voltage shown. A 120 VAC input card won't work.

Brad Waybright

It's all okay as long as it's okay.

 

[IRstuff]

Unclear what PLC they're using, but even cheap single-chip microcontrollers have pulse-counting inputs, which are be capable of counting well into the kHz range, since they typically have dedicated hardware for that sort of thing.

TTFN (ta ta for now)
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[itsmoked]

Do regular VFDs allow pulse inputs and then make decisions based on them? I don't think so? Typically that's what PLCs are for. There ARE a couple of VFDs that have micro PLCs in them. Those would do this job.

WEG CFW100 Series
WEG CFW300 Series
WEG CFW500 Series
FMX drives may also
Mitsubishi A700 series
Hitachi SJ700D series
Delta VFD-E series
ABB ACS880 drives
ABB ACS355 drives have something called 'sequence programming'
Siemens SINAMICS G120

Keith Cress
kcress -

http://www.flaminsystems.com