Today is...
Wednesday, November 22, 2017
Welcome to Control.com, the global online
community of automation professionals.
Featured Video...
Featured Video
Watch an animation of a conveyor stacking operation demonstrating the use of a move on a gear command.
Our Advertisers
Help keep our servers running...
Patronize our advertisers!
Visit our Post Archive
Monitoring a flow sensor over a 4-20mA signal
Need help with verifying 420mA wiring and devices

We have a customer that has a DCS that is monitoring a flow sensor over a 4-20mA signal. We do not have any info on their DCS.

They would like to add a local display(for the flow) out near the sensor. And the displays that would be used is a Omron# K3HB-XAD 24VAC/VDC with a option card inside of it that can transmit a 4-20mA as well (Omron# K33-L1A)

https://www.ia.omron.com/products/family/1535/specification.html

The flow sensor is a FLOTECH F6206-AIV-DS

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0ahUKEwiKlcHf4NTWAhVNGsAKHWjEAFYQFgg0MAI&url=https%3A%2F%2Fwww.instrumart.com%2Fassets%2FFlo-tech-Activa-Ultima-Classic-Quad-Sensor-Manual.pdf&usg=AOvVaw0n8qYNOYO8_A9v6tZDN6ae

My question is: Can i just add the Omron display in series between the flow sensor and the DCS, using the current + and - on the display?
or do i need to use the retransmit capabilities?

1 out of 1 members thought this post was helpful...

You might want to take a look at the "Precision Digital" Model PD6720-0K1.

It is loop powered and doesn't require extra power wires or retransmit requirements. It also provides a NEMA 4X / IP65 enclosure. It also can display flow rate as well as totalizer with reset.

https://www.predig.com/pd6720
https://www.predig.com/indicatorpage/back-basics-fundamentals-loop-powered-devices

1 out of 1 members thought this post was helpful...

>My question is: Can i just add the Omron display in series between the flow sensor and the DCS, using the current + and - on the display? or do i need to use the retransmit capabilities?<

The short answer is Yes
But I agree with Feuchtde, get a modern 2 wire 4-20mA display

No you don't need to use the re-transmit option in fact avoid it.
I didn't try and verify the transmitter will handle the additional load (extra resistance) but it would be unusual to find a modern transmitter that can't handle at least 600 Ohms,

Roy