DF-1/DH-485 Protocol issue


Thread Starter

Mohammad Samir

Dear Gentlemen

i Had one Communication Module it was Suppored By Prosoft Technology (Now Allen Bradly)a SCAN Port With Model Number 1203-GD2 (DF1/DH485 Protocols) Connected to 1336 FB VSD.

I Have and an RTU (Not Allen Bradly Supporting MODBUS RTU RS-232 Or RS-485. I Have The 2 Options. Is There anyway to Let This Module to Work With RTU Without Converters? And for Have Experience DF1/DH485 (is an Serial Communication Protocol With RS-232 or RS-485 an Closed Protocol for Allen Bradly)

Note: I Know There is Modbus Module to Communicate But I Need to Know is There a way to Open This Protocol to Other RTU's


Lynn August Linse

DF1 and Modbus can't directly communicate, so you will need a converter (unless you can use a MSG block to spoof a single Modbus request). Dh485 is quite tight on timing, plus if you have the Ethernet-like port, some will have 24vdc on one of the pins, which could fry you average RS232/485 port if mis-wired.

If you have only one such need, you will save cash and suffering by just buying a Rockwell-to-Modbus conversion unit. Otherwise you might (try to) save us$500, but end up wasting weeks of time and burning out one of the devices anyway ... so in the end you might waste thousands of dollars getting back up running.