Comm problems with Red Lion and SLC500

[ceilingwalker]

Good day all. I have a SLC5/05 that is connected to a Red Lion HMI. They are connected via a network switch. This system has been working good for a couple of years but I have a new issue that has started within the past month that I can't figure out. There are actually two Red Lion HMIs in this work group with static IP's. The one HMI loses comm for up to a minute while the other does not. The distance from the switch to the HMI that is losing comm is less than 100 feet. Does anyone have an idea as to what may be causing this and a possible solution? Thank you much.

 

[dbh6]

couple of things. it would be good to know what kind of switch you are using, managed or unmanaged switch? Does the HMI that's experiencing comms loss for up to a minute happen intermittently or does it happen at certain specific times that itself should tell you a lot. Is their a diagnostics log for the HMI?? having said that you might want to consider what i listed below:

1. since they are communicating over ethernet/IP is the RJ-45 shielded cable
2. Is the network switch dedicated only for the HMI and the PLC or is their another device or is another computer tying into the network, if so their can be IP address conflicts that temporarily cause the interruption.
3. Switch or rj -45 cable or the HMI could be going bad

 

[kolyur]

3. Switch or rj -45 cable or the HMI could be going bad

Was recently in a very similar situation...two G3's connected to a SLC 5/05 over Ethernet. The farther G3 started dropping communication every once in awhile for a few minutes at a time. (It had worked perfectly for several years up to that point.) Turned out to be a bad network cable between two switches on the longer run. Replaced the cable and all is well.

 

[ceilingwalker]

couple of things. it would be good to know what kind of switch you are using, managed or unmanaged switch? Does the HMI that's experiencing comms loss for up to a minute happen intermittently or does it happen at certain specific times that itself should tell you a lot. Is their a diagnostics log for the HMI?? having said that you might want to consider what i listed below:

1. since they are communicating over ethernet/IP is the RJ-45 shielded cable
2. Is the network switch dedicated only for the HMI and the PLC or is their another device or is another computer tying into the network, if so their can be IP address conflicts that temporarily cause the interruption.
3. Switch or rj -45 cable or the HMI could be going bad

How do I know if it is "managed" or "unmanaged"?
It loses comm intermittently, no pattern.
If I get an IP address conflict it will alarm telling me so

 

[ceilingwalker]

Was recently in a very similar situation...two G3's connected to a SLC 5/05 over Ethernet. The farther G3 started dropping communication every once in awhile for a few minutes at a time. (It had worked perfectly for several years up to that point.) Turned out to be a bad network cable between two switches on the longer run. Replaced the cable and all is well.

That is exactly the same problem I am having. I hope this isn't it because trying to pull anything through this conduit is a BIG job.

 

[dbh6]

To tell if it is a managed or unmanaged switch, see if you can get the part number for the switch and look up the manual to verify. Since you said it loses comm intermittently and that you get an alarm if a conflict is present that pretty much eliminates another devices conflicting. It may be your RJ-45 cable as i and Kolyur have described. You can test for a short circuit on that RJ-45 cable by disconnecting both ends and individually testing each pin on one end, if you get continuity between two pins then their is a short

 

[Ken Roach]

trying to pull anything through this conduit is a BIG job

(peeks out from between fingers) What else is in the conduit ?

On the SLC-5/05, make sure you have a Diagnostics file configured for the Channel 1 network port. Monitoring that data file to see if the number of errors or retries goes up at the same time as the connection is lost might help you determine if there is interference or noise.

Professional network installers use sophisticated Ethernet cable testing equipment. You might consider contracting with one to check this cable as-installed.

 

[ceilingwalker]

(peeks out from between fingers) What else is in the conduit ?

On the SLC-5/05, make sure you have a Diagnostics file configured for the Channel 1 network port. Monitoring that data file to see if the number of errors or retries goes up at the same time as the connection is lost might help you determine if there is interference or noise.

Professional network installers use sophisticated Ethernet cable testing equipment. You might consider contracting with one to check this cable as-installed.

Ok Ken, thank you.