MicroLogix 1100 Ethernet dropping connection periodically?

I have an 1100 that I am using mainly as a protocol converter. It Talks Modbus RTU on channel 0 and is connected to a large management system on Ethernet channel 1.

It works great was easy to setup and I am generally happy with it. It will occasionally drop Ethernet Comms to the ControlLogix system I use to communicate with it. It will show a solid green link LED but no blinking activity on the amber LED?

If I cycle the power to the Micro it starts communicating again. Simply unplugging and plugging the Ethernet cable does not work.

I have tried it forced to 10mgbt on both full and half duplex. It does not seem to matter. Sometimes it will stay connected for several days before it stops "talking".

I am not an Ethernet guru. I work with it a lot, but still have a lot to learn.

I guess I need to let it drop comms again and try and ping it before I reboot it. I have not done that yet.

Is there anything anyone knows about the 1100's Ethernet that makes it quirky like this?

RSL

have you tried reversing comms, and msg'ing from the Clx instead of the uLogix.

I think that I will give that a try tomorrow.

Are you interlocking your messaging?

I agree that the crucial thing is to wait for the MicroLogix 1100 to fail to communicate again, then to test it in the failed mode.

1. Check the Link LED on the MicroLogix and on the switch.
2. PING the MicroLogix.
3. Check the http server by typing the Micro's IP address into a Web browser.
4. Browse the MicroLogix with RSLinx.
5. Unplug the MicroLogix and PING it again.

Now you know which, if any, of the features of the MicroLogix aren't working. You've ruled out a bad link (if the LEDs are OK) and ruled out a duplicate IP address (if nothing answers the PING when you unplug the MicroLogix).

The more general question in your case is what constitutes a communication failure. Are you sending messages from the ControlLogix, or from inside the MicroLogix ?

Ken - I have experienced the issue that inspired this topic:

1. Check the Link LED on the MicroLogix and on the switch.
- Both on, (linked) but no activity

2. PING the MicroLogix.
- Time outs . . . no response from uLogix

3. Check the http server by typing the Micro's IP address into a Web browser.
- Can't Ping = no getting to a web page

4. Browse the MicroLogix with RSLinx.
- Can do with DF1 - In this state, the MSG instructions at the micro are erroring out with a D6 code. Power Cycle results in restored communications.

5. Unplug the MicroLogix and PING it again.
- Still nothing . . . no dup ip.