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Remote Meter Data

Remote Meter Data

Remote Meter Data

(OP)
I have a couple of electric meters(GE PQMII).  They have an RS485 output and some 4-20ma outputs. I want to use an existing fiber cable to transmit the instantaneous kilowatts and kilovars to a utility RTU that only has the ability to deal with 4-20ma inputs.  Is there a way to convert the 4-20ma output into a signal suitable for transmission over the fiber line, and convert it back to 4-20ma at the other end.  I believe the only way to do this is to send an RS485 signal over the biber and then install a small PLC at the other end to pick out tht appropriate addresses and convert it through a 4-20ma output card.  Am I correct, or is there an easier and cheaper way?

RE: Remote Meter Data

(OP)
Thanks for the tips, but I already checked black box and b&b. All their devices are slave devices.

RE: Remote Meter Data

There are I/O devices that convert 4-20 to RS-485 as a modbus slave, but then you need a Modbus master on the other end to poll the slave.   If you're going to do that, and you have a Modbus master on the far end, there's no reason not to poll the meter RS-485 directly.

I don't know of a commercial device that converts 4-20 to RS-485 and back again.  There are wireless radios, like Phoenix Contact 1-way industrial wireless radio, that take 4-20 in on one end and output 4-20 on the other, but I'm not aware of any other I/O devices.  

I suspect your idea of a PLC with Modbus master capability (assuming the GE meter is a Modbus slave) is the best bet if you need 4-20 at the other end.

Of course, if you have a PLC, why not integrate/totalize  the values on the PLC?

Dan

RE: Remote Meter Data

In the past I use entrelec module (type PMAO) to convert a modbus data ( from rs 485) to 4 .. 20 mAmps output.

Entrelec is now part of ABB

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