Long distance serial communication


Thread Starter

Heath Lovell

I would like to be able to connect my PLC's underground together. I would like to use a 1 or 2 pair wire.
My PLC's are about 2000' apart with the farthest one being about 4 miles from my computer outside. We currently have CO monitoring systems that can transmit these distances with 2 wires at about 36K. All of the manufacturers of the CO systems have developed their own communication based on RS422 or RS485 or something similar. Does anyone make a "box" that can allow AB's Micrologix to do this?
Thanks for your help,

Curt Wuollet

Tut Systems used to make a product for much longer than usual twisted pair needs. I used it in cases where there was just no economical alternative. Black Bos has a variety of solutions for various protos under the heading of short haul modems. One of the AB guys can tell you if these would be of help. I don't do AB.



Icayan, Erwin

You can use short haul modems with DF1. You will have to decide before you
install if you want half-duplex (two wire) or full duplex (four wire)

Erwin Icayan

You should consider a Bell 202 telemetry modem. Low cost, reliable and easy
to set up. One source is www.nbtinc.com.

Pat Schmid
NBT, Inc
7600 West 27th Street
St. Louis Park, MN 55426
"Nothing But Telemetry"
Office 952-928-8872
Cell 612-202-2822