I have a PLC5 with two blue hoses feeding the DH+ ports. One of these hoses feed the RIO panels. I need to hook up a PC with a KTX card running an MMI program to the last RIO. My question is will I potentially slow the speed of the RIO by doing this?

Can you give some specifics about how many nodes and how much traffic is on it now? How much do you plan to add?

I'm pretty sure that your HMI (politically correct) will actually be hooked up to the DH+ (Data Highway Plus) cable - and not to the RIO (Remote I/O) cable ... secret handshake: the SAME type of "blue hose" cable is used for both DH+ and for RIO communications ... but the two systems are NOT directly compatible ...



note: I guess it's POSSIBLE to hook up to the RIO link - but personally I've never seen it done that way ... the big question would be "what type of data are you trying to communicate over the RIO channel?" ...



it would be a good idea to follow TWControl's suggestion and tell us more ... start by making and posting a sketch of your COMPLETE cabling system (not just the new parts you're adding) and let us take a look at it ... also you need to know that some PLC-5 processors have multiple communication "ports" - and that these ports are configurable ... specifically, just because you THINK it's an RIO link doesn't necessarily make it so ... here's a screen shot that might help you confirm exactly how your channels are set up ...

Gentlemen,

Thank you for opening my eyes. Yes one blue hose is dedicated to RIO and the other is DH+. Out of curioisty shouldn't any blue hose be terminated be it RIO or DH+?

Dear Frank:
The correct answer is that both DH+ and RIO should be terminated, but in limited cases they can be run without termnation.

I have quite a few HMIs using RIO for comms. DH+ is so much simpler to set up, and is readily available now, so I agree that is what you should use if you have the choice between the two.

I have seen every mistake in the book with regard to "blue hose" wiring and termination, and you know what? The stuff works anyway. I have two machines in which the integrator decided to star network part of the RIO links.?!?!? It says right it the manaul DO NOT DO THIS. I complained, but they were unwilling to change since it was (and still is) working with zero faults or retries.

IMHO it will definitely resist noise and intermittent problems better if correctly terminated.