Help With an AB 837T Temp Transmitter

[Ryan_Flowers]

Hello all!

I need to install an 837T Temperature Transmitter (837T-N1N14B25A-D4 to be specific). it is a 4 pin connection. This is reading temperatures and sounding an alarm if out of tolerance. My problem is that I get no 4-20mA signal in from the transmitter in my logic at the input table for channel 0 or any other channel I connect it to. The card is configured for channel 0 to be 4-20mA and be raw/proportional data format. The temp transmitter is connected with a quick disconnect 889d-r4ac-10 four wire cable as follows from my main enclosure:

Black = - DC
White = + DC
Brown = + 4-20mA Signal
Blue = - 4-20mA Signal


My PLC is an AB 1766 Micrologix 1400 with an AB 1762-IF4 analog input module. I tested the other channels with a current loop simulator and got the necessary data at the input table for 4-20mA.

I may just be confused on the wiring, but I would appreciate the help.

Thanks

 

[RClem]

This is the wiring diagram from the installation guide:

 

[parky]

Yes I looked at the diagram, it suggests that it is a two wire device so a passive Analog card with supply to pin 1 and 4-20ma output.

 

[TWS]

https://literature.rockwellautomation.com/idc/groups/literature/documents/in/1762-in012_-en-p.pdf. Page 14

 

[Ryan_Flowers]

I see that yes, I was not looking at the diagram properly and it is only a two wire. So I connected the pin 1 from the cable to + DC source. Then pin 3 to + IN of my analog module. Last the - IN of the module to - DC source.

I see the data on the table now which is good. My new problem is that I am not receiving the correct 4 - 20mA signal according to the thermometer I'm using to compare. The temp range my 837T Temp Transmitter is -58 F to 302 F (-50 C to 150 C). My temperature in my enclosure is around 40 F but my transmitter does not show this value when I put all this info into an SCP to output to a float. Also, my wires from the transmitter to the analog card are only about 20 feet.

SCP:
Input = I:1.0
Input Min = 4000
Input Max = 20000
Scaled Min = -58
Scaled Max = 302
Output = F8:0


Currently I get a negative output in F8:0 with these parameters. I looked through some of Rockwell's knowledge base and don't find anything for my situation.

What is the process for calibrating this within RSLogix 500? Or do I need to change a resolution somewhere?

 

[parky]

I think your scaling is wrong, I believe it should be 0-32,760 have you set the card up properly see these manuals.
https://literature.rockwellautomation.com/idc/groups/literature/documents/in/1762-in012_-en-p.pdf

https://literature.rockwellautomation.com/idc/groups/literature/documents/rm/1766-rm001_-en-p.pdf