Problems Connecting to Micrologix via Ethernet

Scottryan03

Member
Join Date
Nov 2017
Location
Michigan
Posts
50
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.
 
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.
 
===solved===

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.
 
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.
 
Similar problem

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
 
Last edited:
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...).
 
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
 
Last edited:
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.
 

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