Kanalog and 4-20ma transmitter/transducer

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MadTooler
Posts: 81
Joined: Thu Nov 08, 2018 11:57 pm

Kanalog and 4-20ma transmitter/transducer

Post by MadTooler » Sat Dec 04, 2021 2:53 pm

I have another fun hardware connection to work through on my gantry machine. I am upgrading the table with a large vacuum chuck/plate system. For system and job part safety, I will have several pressure transducers/transmitters/senders to monitor vacuum. In the past, systems I have worked on were usually equipped with transducers that interface with a current output of 4-20ma. The current output is usually more immune from interference and can also have much longer cable runs vs. the more common 0.5-4.5VDC analog output units I am finding in the vacuum range (I only found a couple in the 10VDC analog that might work).

Can Kanalog directly work with 4-20ma sensors?

If not, any advice on maximum cable length for 5v(4.5max return analog) signals I may feed into Kanalog? With the transducers I find more available, 0 vac would probably only return 2.5VDC or less with full vacuum closer to 0.5v. Cables would probably be under 10ft long, 22awg, 3 conductor, shielded.

Thank you.

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TomKerekes
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Joined: Mon Dec 04, 2017 1:49 am

Re: Kanalog and 4-20ma transmitter/transducer

Post by TomKerekes » Sat Dec 04, 2021 5:41 pm

Hi MadTooler,

Kanalog inputs are voltage and can not work directly with 4-20ma sensors. In some cases a resistor can be used to convert current to voltage.

How much noise there would be would depend on the environment. But most noise is high frequency and the Kanalog Inputs have a 1.5KHz low pass filter so I wouldn't expect much to get through. I assume the readings don't need to be exceptionally fast so additional capacitors or RC could be added to add more filtering if necessary.

HTH
Regards,

Tom Kerekes
Dynomotion, Inc.

MadTooler
Posts: 81
Joined: Thu Nov 08, 2018 11:57 pm

Re: Kanalog and 4-20ma transmitter/transducer

Post by MadTooler » Sun Dec 05, 2021 2:10 pm

Thanks, Tom.

I appreciate the quick response. I was aware of creating a resistor circuit and of using a signal conditioner. I didn't think Kanalog was able to natively speak with 4-20ma inputs, but did hope there was a sneaky method. Maybe a new feature or add-on board to consider later?

I found some pretty nice vacuum sensors that run on 12vDC+ and output 1-5vDC analog. They seem like a good fit for a real industrial sensor at a more reasonable price than others, as long as I do not let my coolant get far enough into my vacuum plumbing and spoil the dry air only sensors :lol:

For your ref: SMC PSE541 series.

Thanks again.

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