4-wire transmitter with 120Vac?

Question

4-wire transmitter with 120Vac?

CuriousElectron (Electrical)

(OP)

13 Mar 19 05:37

Hi Gents,

I need to spec out a 4-20mA instrument that would come with a local 120VAC power supply. I'm measuring hydrostatic pressure at a remote site and need to bring 4-20mA signal back into the plant. No 24 Vdc available but 120VAC is available. Any recommendations for a brand?

Your typical GE Drucks and such all seem to be loop powered

Thanks,
EE

ScottyUK (Electrical) · Answer 1 · 2019-03-13 06:47:23

How 'remote' is this transmitter? Is there the option to run two-wire loop-powered, or provide 24V power via a spare pair? Can you provide a small PSU 120V/24V locally and use a standard transmitter?

I'm sure you've considered these possibilities, but you haven't explained why they won't work.

itsmoked (Electrical) · Answer 2 · 2019-03-13 08:14:21

Not understanding..? This is what loop powered devices are for. Power it from the place that wants the data over the 4-20mA line. That's why it's 4mA not 0-20mA.

Keith Cress
kcress - http://www.flaminsystems.com

PawSoxRule (Electrical) · Answer 3 · 2019-03-15 14:11:19

Different options to consider. Sometimes equipment does not come with its own power supply and you have to purchase one separately. Another thing to consider, is if the equipment takes 24 VDC but you only have 120 VAC at the site, you can buy a power supply that takes 120 VAC and outputs 24 VDC. Another option, is having a small enclosure or junction box located remotely where you take care of the power supplies and most of the wiring. Then just run a cable/wire bundle from the junction box to your equipment.

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4-wire transmitter with 120Vac?