RSNetWorx with Controlnet

[Help Please]

I have a compactlogix L43 with RSlogix 5000 in slot 0 and in slot 1 the 1768CNB and slot 2 a 1768ENBT. The problem is a cannot get online with the 1768CNB controlnet module to configure it. It has only one media port(A) and is flashing the red led for (A). The status led is flashing green. I have tried to get online through the control logix and through the NAP and have not been successful. Any ideas on what I am doing wrong

 

[Ken Roach]

Is anything connected to the ControlNet port ? Flashing red is the normal Channel indicator when there's nothing connected. Ideally, you will have ControlNet taps, ControlNet trunk cable, two terminators, and two or more individually addressed ControlNet devices.

Does the 1768-CNB show up in the backplane browse (over Ethernet or via the serial port of the L43 controller) ?

Doe the 1768-CNB dot matrix display show any useful codes ? Typically this display will tell you if there's a backplane error or a network problem.

 

[Help Please]

Thanks for the quick response. Currently we have one ControlNet tap coming out of port A (our only port) with a terminating resistor on each end. We are bench testing so we do not any I/O to put in the network. When we create a new RSNetworks file we can see the PLC, controlnet, and ethernet modules. I can see the 1768-CNB through linx and when I goto Set Online Path in the network properties. The CNB is flashing NET ERR %C01 KpOi nC00 A#02

 

[mellis]

You didn't try connecting an ethernet cable directly to the module did you? That's a ControlNet port, not ethernet. You need a controlnet interface to use that port.

However, you should be able to go in thru the 1768-ENBTs ethernet port with no problems.

More information on what you are actually doing will be helpful. Screen shots would be great too. It could be something simple, but without looking over your shoulder it's hard to say.

 

[mellis]

The key part in Ken's reply...

Two or more individually addressed ControlNet devices.
This isn't optional. You must have devices to get the network configured. The CNB counts as one, but with no other device, you're not going any farther.

The minimum network is 2 taps with a terminator on each one, a length of trunk between them. One tap plugged into the CNB, and the other tap plugged into something else.

If you just want to get familiar with the process of setting up ControlNet, I'd suggest asking your distributor to lend you a simple ControlNet I/O module like point or flex. ControlNet setup is not necessary to get your programming done, if the I/O is not in the same cabinet, it's usually a field task anyway.

 

[Help Please]

I have two taps but no other devices to communicate with. I am trying to go through the ENBT card not the actual CNB itself. If I for sure have to have at least two addressed nodes then I guess I am dead in the water. Thanks

 

[Ken Roach]

As my colleague mellis stated, ControlLogix I/O configuration on ControlNet is done entirely inside RSLogix 5000 so there's nothing for RSNetworx to do except go out and create a network schedule based on the physical devices and the requested connections.

The module is doing exactly what it's supposed to do when connected to nothing; it's waiting, and letting you know that there's nothing configured or connected.

NET ERR Means there's a network error, because there's no other nodes.
%C01 The CNB module's CPU Utilization is at 1%.
KpOi The Keeper is Offline and Invalid. No surprise, as there's no schedule.
nC00 The Number of CIP Connections is zero.
A#02 The CNB is ControlNet Node 02, connected to channel A.

You can go ahead and create your I/O tree in RSLogix and it will just sit with error icons until you actually connect your hardware.