Problems Connecting to Micrologix via Ethernet

[Scottryan03]

Good morning,

I have a bizarre issue with connecting directly to a Micrologix 1400 via ethernet.

It recently popped up on a service call when connecting directly to the plc, I could not ping it and could not see it in rslinx. Everything was what it should be as far as my ip and subnet. I ended up connecting using DF-1. When I got back to the office I tried one on the test bench and had the same result.

Some interesting things are: After attempting the Micrologix connection if I disconnect my ethernet cable and plug it into a compactlogix I can ping and see the compactlogix, then I disconnect from the Compact and plug back into the Micrologix I then can see and ping the micrologix. Very weird. Also, if the micrologix is connected to a switch all is well.

I've never had an issue connecting directly to a Micrologix. Has anyone else experienced this issue and/or have any suggestions to fix it?

Thanks for the responses.

[cwal61]

Try a cross over cable instead of a patch cable.

[Scottryan03]

Originally Posted by cwal61

Try a cross over cable instead of a patch cable.

Good call. I will try this. I find it weird I've never had this issue before with a straight cable though.

[Scottryan03]

The crossover cable did not work. I cannot communicate with a micrologix or compactlogix. Any other suggestions?

[cwal61]

Ethernet port on the Laptop is going bad or bent pin on laptop port. Sometimes works sometimes don't. Do you have a USB to Ethernet adaptor? We have used the StarTech.com Part#USB31000S and they work well for quickly adding an Ethernet port.

[Scottryan03]

Originally Posted by cwal61

Ethernet port on the Laptop is going bad or bent pin on laptop port. Sometimes works sometimes don't. Do you have a USB to Ethernet adaptor? We have used the StarTech.com Part#USB31000S and they work well for quickly adding an Ethernet port.

I found a usb to ethernet and it worked. Thank you. I can't quite make sense of why I can connect to other devices, but I will take it.

Thanks again.

[Ken Roach]

I can't quite make sense of why I can connect to other devices

It might be an ARP cache issue in your operating system; flush the cache and see if you can connect to those devices with your existing port.

This isn't usually necessary (and it is a Windows thing, not a Rockwell thing) but it can't hurt to try.

[Adesdrac]

Hey there, i have a similar problem with one client, I have a Micrologix 1400. I can conect to it via DH-485. but i cant connect via ethernet.
*My Laptop have the IP 192.9.150.253
*PLC have 192.9.150.51
*I CAN ping PLC with Laptop (4 packages send, and 4 packages recived)
*I CANT see my ethernet adapter is connected to something
*Ethernet IP Driver on RS Linx using my ethernet adaptor dont find anything
*Ethernet Devices Driver on RS Linx using my ethernet adaptor dont find anything
*I did the same test with 2 different Laptops
*I can see other Micrologix 1400 and compact logix in the ethernet Network in the 2 Lap Tops where i was testing.
*I connected an USB to Ethernet Converter, and is working on PC, but cant see the PLC in RSLinx, but i can ping the PLC with that Converter to PLC

for mee it seem port ethernet is damaged.
questions:
*Is something that i can do to fix that?
*Can i use somehow DH-485 port with some ethernet converter to add that micrologix to the network? (it have some connections with 1 HMI and 1 Compact Logix)
*Or i have to buy a new PLC?

TYVM in advance for your time to look in to this problem

[joseph_e2]

Try a different cable. Believe it or not, I chased down an issue where I could ping it but RSLinx/RSLogix wouldn't talk to it. I swapped the cable and it started working. That was my last ditch "hail Mary" thing to try after a LONG time banging on it, so I ended up cutting the end off of the cable so I didn't get bitten again (in that shop, it wasn't unusual for stuff that had been thrown away to find its way back into a stash somewhere, so we got in the habit of breaking things enough they couldn't even be attempted...).

[Adesdrac]

Ty, I tryed that, I buyed a New ethernet cable, no luck, then I made a New one, But no luck. I guess in this case is the port is damaged

[joseph_e2]

I wonder also if the port is set to auto-negotiate its speed (if that's an option on that ML). It could be that plugging into the CompactLogix with auto-negotiate enabled sets it up to work. Could be something to look at.