RIO comms issues

[Buzzen]

We had A/B come out and install new controller(see image of network) to communicate with old RIO rack PLC-5 era. I have issues. The outputs that control pumps are dropping off due to lack of communications I believe anyway. Is this set-up even "good enough" to communicate with new L7 contollers? Please note that I am speaking of the 1756-RIO. The 1756-DHRIO has the error due to channel B not being used.
Attached Images

 

[Ken Roach]

The outputs that control pumps are dropping off

Are all of the outputs turning off at once ? Do they come back on by themselves or do you have to perform some kind of reset ?

The first test I would perform is to perform a GSV to get the EntryStatus object from the Module Object for the 1756-RIO. That will tell you if the connection from the ControlLogix across the backplanes and 1756-ENBT modules is reliable.

The next step is to check the diagnostic counters for the RIO channel on the 1756-RIO module to find out if there is noise or bad signal that's causing dropouts of the RIO network itself.

How many RIO adapters do you have in this system ?

My experience with 1756-DHRIO and 1756-RIO migrations has turned up quite a lot of bad or degraded wiring over the years. In general it seemed that the PLC-5 was better about tolerating bad signals than the 1756-DHRIO was, but once we got good signal the DHRIO and RIO scanners were fine.

 

[Buzzen]

There are 7 remote racks that all run on blue hose. The 1756-RIO termination has two blue hoses attached to it, one "trunk-line" runs five racks and the other runs two racks one of which is a A/B VFD (1336 plus)using a 1203 remote I/O communications module.

 

[Ken Roach]

Okay, sounds like an ordinary-sized RIO network.

Are you running at 57.6, 115.2, or 230.4 kb/s ? Are terminating resistors connected to the physical ends of the network ?

Remember that the terminating resistors go at the physical ends of the network, not necessarily at the PLC. And you use 82 ohm when you're running at 230.4 kb/s versus 150 ohm when running at 57.6 or 115.2 kb/s.

I haven't used the 1756-RIO for several years but I know there are media diagnostic counters that will let you see if you have good signal on the RIO network.

 

[Buzzen]

We are running 57.6 with resistors at both ends. One thing I have done is launched the rio configuration tool>Monitor>Debug Log. And this is the error: Transmit retry rack 7
Receive Timeout rack 7
That is the rack that the pumps are shutting down on. They are not restarting anymore on their own. At one time they were. I took out the auto-restart function, hoping to catch errors. No luck. I looked at the GSV functions which I have never used. Question:would I load the .rio file under object name?

 

[Buzzen]

Here is the Diagnostics Counters on the RIO network.