Rslogix5000 ControlNet

[kbn_120184]

i am facing problem with controlNet which communicating with Powerflex 700 drives.
the communication is healthy with drives for certain time for example 12 hours more or less, than immidiatly communication error occurs, solid red LED is on the controlnet card. after switching On/Off the power of PLC rack then it will be OK for certain time then again the same problem occurs, it is repeating.

any one know about the main cause of this proble???

 

[dmargineau]

A wild guess: subpar media (connectors, taps, coax cable, electric "noise")...
http://literature.rockwellautomation.com/idc/groups/literature/documents/in/cnet-in002_-en-p.pdf

 

[MNMark]

In my experience 98% of the cause of controlnet problems is due to poor installation. The media (cable, connectors, taps, etc) is extremely particular as to how it is installed. From what you described, I would guess that you are constantly generating errors on the network, and when the error buffers overflow, you fault. I've seen this before, and it almost always indicates poor installation. Is this a new installation? If not, have you recently made any changes? You can monitor errors on the CNB via RsLinx by right clicking and selecting properties (I think, I'm not in front of my test rig at the moment). For troubleshooting installation issues on the network, I recommend the 1788-CNCHKR Controlnet NetChecker. I have used this little beast before and it is very handy. Check with your distributor and see if they have one that you can borrow.

 

[dmroeder]

I agree with dmargineau and Mark. The NetChecker is a must for noise checking. Proper grounding is important, especially if you are using any DIN rail mounted interface modules.

I faced an issue with a network that took quite some time to solve. We had many people look at our network including Rockwell and nobody could find the source of the problem. One particular drive (1336 FORCE) on a network of about 2 dozen drives would fault a couple of times a day. There was noise on the network, but we couldn't find the source. I re-terminated every connection, replaced cable, replaced the drive, replaced the scan port, cables from scan port to drive. Basically everything near that drive was replaced.

One weekend we were cleaning MCC buckets and we noticed that a scan port about 4 MCC doors down from the suspect drive wiggled when vacuuming it out. Snapped it back on the DIN rail and then the light bulb went off. I went and got our noise checker and what do you know, the noise was gone. The issues wasn't coming from the drive that was faulting, it was from a totally different drive. Wasn't even the one immediately next to it.

 

[Ken Roach]

solid red LED is on the controlnet card.

Do you mean the ControlNet interface module on the PowerFlex drive (the 22-COMM-C), or the ControlNet bridge module for the ControlLogix (1756-CNB(R)) ?

There are three LEDs and a scrolling display on the 1756-CNB modules. You need to know and explain the state of all four of those indicators.

This might me a media problem, it might be a hardware problem, and it might be a firmware problem.