DH+ ethernet bridge help

[cncsparky]

Previously working PV1500 stopped talking to the PLC5, 'error' shown in all screens.

First experience with a CLX bridge.
Slot 0 L55 v12 no program but still goes into 'Run' mode
Slot 1 1756-ENET
Slot 2 1756-DH/RIO

How do I troubleshoot this?
Ethernet lights blinking as expected, can comm to PV1500 via laptop
DH+ seems to be happy

A few config pics attached.

 

[Ken Roach]

How long ago was that PanelView Plus commissioned, and what firmware revision is it running ?

It was not until fairly recently that RSLinx Enterprise (which runs onboard the PanelView Plus) could bridge through a 1756-ENxT, then a 1756-DHRIO, to a PLC-5 on DH+.

RSLinx Classic could, but that's not what ran on the PanelViews.

Because that controller and Ethernet module are so old, it's likely that the PanelView was actually reading tags out of the ControlLogix, which was then reading and writing the PLC-5 via the DHRIO using MSG instructions.

 

[Ken Roach]

From the "Getting Results" quick start guide for FactoryTalk Linx:

>• Starting with version 6.20.00, FactoryTalk Linx provides the ability to communicate using solicited messaging with Allen-Bradley controllers using PLC-5 or SLC-5 messaging over the DH+ network without having a 1784-PKTX card installed on the computer. This is achieved by using the 1756 EtherNet module bridging across a ControlLogix chassis to a DH+ network connected to a 1756-DHRIO module.

https://literature.rockwellautomation.com/idc/groups/literature/documents/gr/lnxent-gr001_-en-e.pdf

If this is a pre-v6 PanelView Plus, then I'm not sure it can be upgraded to run FTLinx that will support that sort of direct bridging.

So your best bet is to go recover that ControlLogix L55 program.

 

[cncsparky]

Thanks Ken. I will check the PV firmware version but I’m sure its below v6.

Why does the L55 look ok but doesn’t have a program in it? RS5000 says no program to upload, but the run light turns solid green after booting.

 

[Ken Roach]

If you've got a depleted RAM backup battery and no nonvolatile memory device installed and configured, then it is very common for a 1756-L1, -L55, or -L6x to lose its user program when you cycle power.

The controller will power up faulted because of the lost user program, but will enter RUN mode even without a user program. It's just sitting there executing the operating system with no user tasks and a default controller name.

15 years ago when you had a PanelView Plus that wasn't within wiring range of a DH+ network and couldn't be fitted with a DH+/RIO option comms module, it was common to put a ControlLogix to work messaging to a PLC-5 and representing that data on EtherNet/IP in PLC-5 style data tables or ControlLogix style tags.

I don't have a PV+ handy to look at but I think that if you got into the Configuration menus and looked at the RSLinx Enterprise shortcut definitions, you will see the shortcut pointed to the L55, not through the ENET/DHRIO/DH+ path.

 

[cncsparky]

The L55's battery is good, I unplugged it with power on and the battery light came on. Off when plugged back in.

During bootup, the OK is red then turns green same time the RUN turns green.

Looks like this L55 has 1756-M16/A memory expansion. Is this non volatile memory?

 

[joseph_e2]

The -L55 processors didn't come with on board memory. You had to order the memory module separately, or select a catalog number with it included, like 1756-L55M12 or -L55M16. It still needs the battery backup.


The solid red OK LED indicates a non-recoverable fault that cleared the project from memory. I'm not sure if that light turns on during boot-up normally or not. See page 131 of the attached manual for an explanation of the LEDs.


*Never mind, it's too big. Try this link:
https://nicontrols.com/media/pdfs/AB_ControlLogix_CPU_UserManual.pdf

 

[Ken Roach]

I can only speculate about why that L55 doesn't have a program in it now.

The L55M16 is a volatile memory module; the 5th character indicates 1=RAM, 2= NVRAM.

Maybe the battery wasn't connected in the past, maybe the L55 major-faulted for a different reason and cleared its program, maybe someone downloaded firmware and left it with a blank program.

If you need to reverse-engineer the program, a system like this very probably left some good hints: if you are able to open the FactoryTalk View Studio file and look at the various tag references, the tag names probably give you some hints about which N, F, or B data files that the ControlLogix is "brokering" for the PLC-5.

 

[cncsparky]

If you need to reverse-engineer the program, a system like this very probably left some good hints: if you are able to open the FactoryTalk View Studio file and look at the various tag references, the tag names probably give you some hints about which N, F, or B data files that the ControlLogix is "brokering" for the PLC-5.

Tried opening the View file and it is apparently too old of a version for my software. I think i have FTView v8.1 loaded.

This is likely to be a good candidate for an Ignition conversion.

Thanks for the help!

 

[Ken Roach]

If you want me to give it a try, drop me a message via PMs.

While Ignition does a lot of things very well, I don't know how you would connect it to DH+, except maybe via RSLinx or FactoryTalk Linx that can navigate that bridged network.