Timeout Errors on Remote 1756-ENBT

Hi there,

I've just brought a remote rack of I/O online and I've having a lot of intermittent connection timeouts on the I/O modules (sometimes the ENBT too). Its a 10 slot rack with 1 x ENBT, 4 x DI, 1 x DO & 4 x AI.

The error code is 16#0204.

The RPI for Digitals was 10ms and Analogs 80ms. I have increased these to 20 and 100ms respectively and still no success. I've even went to 750mS. Some times half the modules are running and the rest are faulted, then other times the entire rack is in fault.

As far as I/O configuration is concerned I have 4 more remote racks on same network with no problems at all.

Has anyone any suggestions what could be the problem?

Your EtherNet/IP communication module may experience intermittent network connectivity due to:
•a duplex mismatch.
•electrical noise induced into a cable or resulting from a Logix/switch ground potential difference.
•bad hardware, such as a cable or switch part.

search for enet-um001_-en-p.pdf

Before troubleshooting this problem, familiarize yourself with these Ethernet statistics, or media counters.

Make sure your commons on your IO cards (especially the analog) are wired properly. I've had issues with complete comms dropouts on some enbt's from this.

My first thought actually is that you are overloading the Ethernet switch. Can you tell us what switches you are using and roughly how this and the other chassis are physically connected?

OG