4-20 mA output to transmitters 1

[notredave68]

All,
I am doing a wiring diagram and need some help. I need to run instrument pairs from analog output board of a GE GF868 ultrasonic gas flowmeter, see attached pic, to respective transmitters. The plant uses traditional black (+24vdc) and white wires. Can someone tell me for one loop, what wire color lands on the signal terminal. I am assuming that the black will land at the + terminal of transmitter. Thank you in advance.

 

[MikeHalloran]

I couldn't make sense of your file.

Here's what I think I know:

Any 4-20mA current loop comprises three components:
- a transmitter that limits the current through it in a controlled way.
- a receiver that measures the current through it, and typically sends the measurement data to some sort of recorder or display.
- a source that will apply sufficient voltage to cause current to flow through the loop.

Each such component has two terminals.

So there are six wires in a loop, some of which may be internal short jumpers when the source is combined with something else.



Mike Halloran
Pembroke Pines, FL, USA

 

[controlnovice]

Call your GE rep or their call center...

______________________________________________________________________________
This is normally the space where people post something insightful.

 

[danw2]

Your attachment 'E' is a blank document, as far as I can tell.

The installation guide for the GE GF868 is downloadable from here:

https://www.gemeasurement.com/flow-...ow-gf868-flare-gas-mass-ultrasonic-flow-meter

Pg 18 is a drawing showing the wiring terminal locations and pin functions.

There appear to be two sets of AOs. I'm guessing that the 2 pair of AOs is the standard pair, the set of 4 AOs is probably an option board. The labels on the pins AO are SIG(+) and RTN(-). That's pretty straight forward (+) to (+), (-) to (-).

I assume one maps variables to the AOs with the configuration software/firmware.

There is not mention of 'passive' or 'loop powered' or 'sinking', and since the flow meter is line powered, I would conclude that the AO's are active, powered outputs.

If the receiver system you are connecting to has only provision for powering a loop powered signal, then you will need a loop isolator module whose output is loop powered to be compatible with the receiver unit.

pg 14, sec 1.7.6 is titled "Wiring a 0/4-20 mA Analog Inputs Option Card".
Analog inputs are for pressure and temperature transmitter signals used for mass flow calculations.
Field transmitters connect to Analog inputs, not analog outputs.