DeviceNet

Gentlemen,
Quick question, how do I leave a vfd in the network but basically want the network to ignore it?

It depends on what PLC you are using and how you are communicating with it.

In rslogix/studio 5000 you would put a checkmark next to "inhibit module", but make sure there is no watchdog or any other logic that requires the drive to be present.

A pause icon next to the drive icon will appear just like in the picture.

In a ControlLogix with EtherNet/IP or ControlNet, the connection inhibit is done in the I/O tree as seen above.

On DeviceNet, the connections are all done in the Scanner module's Scanlist Configuration. RSNetworx for DeviceNet software is required to created, edit, upload and download scanlists.

To disable a device in a scanlist, all you have to do in the Scanlist Editor is select the device in the "Scanlist" side of the pane and un-check the "Node Active" box.

You could also simply remove the device from the scanlist.

Not the OP, but is there a way to do this from the program, instead of via the engineering software?

Yes on both.

In Logix 5000 with the EtherNet/IP and ControlNet connections, you can programmatically "check the box" for the Inhibit Connection setting on the Connections tab.

The Set System Variable (SSV) instruction will do the job. You set it for the Module's MODE object, and write a value of 4 to Inhibit, and a value of 0 to un-Inhibit.

The RA Knowledgebase has a good example, in Article ID # 52041. (TechConnect Required).

This can also be done in DeviceNet with a CIP Generic Message to the Scanlist object.

The details are dependent on platform (SLC, PLC-5, Logix) and firmware support for the feature. Modern DeviceNet scanners allow you to do connection Active/Inactive changes during runtime without interrupting the rest of the data flow.

It's a fairly expert-level feature, but I'd be glad to pull out my notes on it if necessary.

Ken Roach said:

Yes on both.

Click to expand...

Thanks for the info. I don't have any immediate need for this, it was more just a nugget to file away in the back of my brain in case I need it some day.