1769-L30ER losing network settings

[wilkerson29847]

Good morning everyone.
I have a situation that is really stumping me. I have three separate but identical machines, all running 1769-L30ER PLCs, and they completely lose their network settings. None of them have memory cards installed, all three have the setting of "Manually Configure network settings" checked but all three of them will zero out all of the network settings in them. See attached screen shot of one of them. I then have to connect via the USB connection on the front to reset the network settings to what they are supposed to be.

Does anyone have any ideas what could be causing this?

 

[drbitboy]

Some questions to help narrow this down.

What Firmware Revision ?

Are you losing just the IP Address or the entire PLC Program?

Is the PLC in RUN or REM mode?

[posted without a bit of irony cf. here]

 

[wilkerson29847]

Version 30.14
I am only losing the network settings (IP, Subnet Mask and Gateway)
The PLC is in Remote

 

[arpus4KM]

Version 30.14
I am only losing the network settings (IP, Subnet Mask and Gateway)
The PLC is in Remote

is there a memory card installed with a program stored in it?

 

[Ken Roach]

Well, that's not normal.

>all three of them will zero out all of the network settings in them.

Do they appear to do this while powered on in runtime, or after a power cycle ?

Does the control system stop functioning when this occurs, like going into PROG mode or appearing to restart ?

Background: PLC-5 and SLC systems store the network parameters in the user program, but ControlLogix has always stored the TCP/IP configuration object in the EtherNet/IP module itself. If you unplug a 1756-ENx and move it to another chassis without a CPU at all, it will retain its IP address/subnet mask/default gateway.

CompactLogix also segregates the TCP/IP configuration from the user program. It might be stored physically on the same board, but it's logically separate.

Loading a program from a CF or SD card does set the TCP/IP object because that's a full image of the controller, from firmware to user program to other nonvolatile settings. So that's worth looking into.

It's also possible to programmatically change the TCP/IP object. I recommend against trying to get that fancy, because it can backfire if a future user doesn't understand how it works, but some programmers do it. You'll look for CIP MSG instructions aimed at the 0xF5 TCP/IP Object.

It might be possible to attempt to commit an invalid configuration, like having the Default Gateway be on a different logical subnet than the IP Address. That might result in a zeroed-out configuration that doesn't make itself known until after a power cycle.

 

[BinderNut]

Is BOOTP disabled? Use the BOOTP utility (it's somewhere in the RSLogix5k Tools menu folder) to set the IP and disable BOOTP.

 

[Operaghost]

The OP said there wasn't a memory card. That would have seemed to have been the most logical cause for this. He also posted a picture showing that BootP is disabled. And, it does not appear to be re-enabled. It is still set for Manual, but the fields are all reset to zeroes. I'm also inclined to think this is something in the program causing this. I'd be looking for CIP Write MSG instructions to see if there is some code overwriting these settings.

I have always preferred to use RSLinx Classic to set the IP address rather than the Logix software. Just a personal preference.

OG

 

[arpus4KM]

The OP said there wasn't a memory card. That would have seemed to have been the most logical cause for this. He also posted a picture showing that BootP is disabled. And, it does not appear to be re-enabled. It is still set for Manual, but the fields are all reset to zeroes.

I'm also inclined to think this is something in the program causing this. I'd be looking for CIP Write MSG instructions to see if there is some code overwriting these settings.

OG

Looks like I glazed over that detail.

Maybe OP can post up the program to be looked over.

 

[Operaghost]

...Maybe OP can post up the program to be looked over.

That would help. Scary thing is that if it is a MSG, it could be remote. Since it is happening to all the PLCs that could mean a central controller is doing this, or that the same code is being used in each system.

And...the SD card comes with those controllers. Someone must have decided to remove them.

OG

 

[arpus4KM]

That would help. Scary thing is that if it is a MSG, it could be remote. Since it is happening to all the PLCs that could mean a central controller is doing this, or that the same code is being used in each system.

And...the SD card comes with those controllers. Someone must have decided to remove them.

OG

it was.... The IT Department!!!!

 

[p8p8]

BinderNut
is right.
It is very likely you did not disable it.
If you did not disable it, when PLC lose power, you will lose IP address.
You do not need to be too fancy, try simple solutions first.
after you using BOOTP software to change the ip address, disable BOOTP/DHCP(make sure you successfully disable it, PLC should be in Run or Remote run to do it), then cycle PLC power, see if IP address still there.
If this does not work, then try other fancy solutions people replied here.

 

[RonJohn]

it was.... The IT Department!!!!

Out of curiosity, was there a duplicate IP address involved? We had that issue with a particular CompactLogix processor until our IT put a stop to it! Turns out there was a rogue device setup for DHCP that booted up faster than the 1769-L30ER after a power outage.