AB Protocols

plc noob · Mar 5, 2009

I am trying to learn AB networking systems and have a few questions

First is DH485 a 4 wire rs 485 network protocol? This is my best guess

What is the difference between Data Highway,DH+,and RIO or Remote I/o or are some of these the same just different terminology used .

I assume some of these are older netwoks and i have found limited info on them and the differences between them.

Also can someone point me in the direction of some good literature and training aids for these networks?

Thanks

mgvol · Mar 5, 2009

For DH-485, take a look at Appendix B in the first link and for DH+, Appendix D.

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1747-um011_-en-p.pdf

For Remote I/O, take a look at Chapter 6 at this link:

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1785-um012_-en-p.pdf

Hope it helps!

Mickey · Mar 5, 2009

Here's another link for cabling on the DH,DH+ and DH485 networks

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1770-um022_-en-p.pdf

nettogrisen · Mar 5, 2009

This is a cutout of one of the awsome "Free PLC Programming Tips" -emails that this site offers.

I suggest that you sign up if you havn't already.

plc noob · Mar 5, 2009

Would RIO be DH,DH+,or DH485?

Thanks for the links guys

Mickey · Mar 5, 2009

plc noob said:
Would RIO be DH,DH+,or DH485?

Thanks for the links guys

None of the above.
RIO uses the same wire ( Blue Hose) as does the DH+, but the protocol is different.

plc noob · Mar 6, 2009

Mickey does standard DH Data Highway use blue hose also?

plc noob · Mar 6, 2009

In my Facility i think we most likely have all of them.

Also do you or can you use the same remote i/o mdules such as an asb on DH+ and RIO or do they use different adapters for remote I/O racks?

bernie_carlton · Mar 6, 2009

RS-485 can be host to a number of different protocols. RS485 can be implemented as 4 wire - only one master, and 2-wire, which can, conceivably allow multimaster (such as DH485) protocols.

These are similar to the languages spoken on a single telephone line. It is critical to note that the different protocols (DH485, DH+, RIO etc) cannot co-exist at the same time. They each want to use the lines in a mutually incompatible method.

Then comes Ethernet. Ethernet is a method of connection PLUS a low level protocol which allows multiple different protocols to ride on it.

Mickey · Mar 6, 2009

plc noob said:
Mickey does standard DH Data Highway use blue hose also?

Yes,
All questions about hardware and cabling are answered in the PDF posted in post #3 of this thread.

AB Protocols

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