Ultra 100 Communication using Host commands over RS485 4-Wire


Thread Starter


I have a project that I have never attempted before coming due.

I need to trend varibles in a Ultra 100. (can not use the analog out, already being used)

So I would like to set up a RS485 4 wire network, (15 drives) , master polling device will be a Controllogix 1756-L55M12. I will be using a RS232 to RS485 adapter on the com of the processor.

The Host commands are ASCII.

HAs anyone done this before or have any insight ?

Any help would be appreciated.


Paul Cunningham

A company called Quartech makes a magic box that will handle the details for you and get data to and from your drives and your PLC. We use it to communicate between an A/B PLC5/40 and four Ultra 200 drives. The quartech 9112 module connects to our DH+ network and does all the work for us after a little programming. Visit http://www.quartechcorp.com/products.htm

There are drivers for your application, and you then won't need to do the 232 to 485 conversion using special plc cards.