rslogix5000 1756 faults when going online

[FireWolf71]

The machine is running production. When trying to go online with the laptop the whole machine looses communication and faults out. Drives, HMI, and PLC.
No other communication issues while running. HMI and drives work fine.
Just the act of going online faults everything. Both from the office and directly at the plc will make it fault.

 

[Operaghost]

Fault code?

OG

 

[alan_505]

Processor type, Comms card, firmware level for processor?

 

[MarkNightingale]

IP Addresses?

 

[FireWolf71]

Fault code?

OG

Can't communicate with RSLinx (Error 715-80042535)

 

[FireWolf71]

IP Addresses?

I've tried both IP networks in the cabinet. One is for the cabinet the other is for the building network.

Plugged in and tried both com cards with correct ip addresses for each.
I am able to communicate with all other machines in building.

 

[FireWolf71]

Also should note that the Battery is dead and program is currently running off of memory card.
New battery should come in the next couple of days.

 

[James Mcquade]

What is the IP address, subnet mask for the plc, hmi, other components connected to the plc?
what is the ip address and subnet mask you are using on the laptop?
is your ethernet port enabled?
regards,
james

 

[Ken Roach]

Welcome to the PLCTalk forum community !

Unfortunately you're not giving much detail to work from. It's a 1756 series controller, but those have been around for 20 years so we're asking which model and firmware revision so we've got some context.

The "whole machine losing communication and faulting out" could be the controller itself going into a fault state, or the controller's network connections could be failing, causing functionally a failure of the control system. A close inspection of the CPU indicators is the first step, particularly if the "OK" LED is flashing or solid red.

Can you go online after the fault and read a fault code ? How does the system recover; a power cycle, or just a RUN/PROG/RUN cycle of the keyswitch ?

I'm curious if "the act of going online" means that the problem occurs when you literally click the "go online" button in Studio 5000, or if it happens when you first connect your PC to the network, or when you browse the controller in RSLinx Classic.

Of course it's not normal behavior for a 1756 controller to fault, or lose communications, when you go online with Studio 5000.

So let's gather up as much information as you can and post it, including the type of Ethernet interface you are using, and if there are any indications on that module of network failures or conflicts.

It's certainly possible that your controller is so heavily loaded that it tips over a watchdog or load threshold and faults when you ask it to both run the machine and talk to Studio 5000. But the controllers are generally built to refuse Studio 5000 the resources they're requesting, rather than dropping I/O connections, when asked for more than it's got to give.

 

[tlf30]

As stated, the specific model of the controller is necessary to further troubleshoot.
Is the PLC program on the machine from a 3rd party vendor?
I worked on a heater once that monitored the number of connections to the controller and would intentionally fault the controller when attempting to go online with it. (I immediately removed that logic)

Do you have an offline copy of the project you can look at, or are you attempting to upload when you go online with the controller?

 

[FireWolf71]

Some more info I gathered.

Before I Started working in this location.
Back in December, The HMI was Punched/broken by a disgruntled Operator/employee
Due to the backup battery being dead, the program was lost. For some reason no one ordered a battery. The new one will be here in a day or two.
They could not reprogram the PLC. Probably because of similar issue I'm having now. A corporate Engineer loaded the program onto the memory card and this is how it is now operational. One problem I'm thinking is that the revision version is not compatible with laptop version.

According to the offline program

It's a 1756-L61 ControlLogix5561 and firmware 17.2
Comm Cards are both 1756-ENBT

I can see the PLC and both comm cards active in RSLinx

I know the OK LED goes red after trying to go online. Not sure if it was blinking or solid. I Will have to wait as the cleaning crew has it locked out.

"Can you go online after the fault and read a fault code ?"
Cannot go online at all.

"How does the system recover"
Just cycle of the keyswitch and reset all drives and HMI faults once communication is restored.

Faults when I click the "go online" button or "upload"

No issues with other machines when needing to change IP addresses or other configurations on Laptop.

 

[Ken Roach]

Sweet, thanks for the context, detail, and hilarious-as-long-as-it-doesn't-happen-to-me backstory.

The 1756-L61 is old enough not to have the useful dot-matrix scrolling display (but the 1756-ENBT has one !), but rather just indicator LEDs.

The indicator to look at on that 1756-L61 is the "OK" LED on the lower right. If it's solid green there's an operable program (even the default that is loaded after a power loss without a battery).

Solid red means an unrecoverable fault; you have to cycle power.

Flashing red means a recoverable fault, one that you can clear by going online or with a keyswitch cycle.

>version 17.2

That version was unpleasantly buggy, to the point where it was removed from the webserver and retired. In fact, RA is at the point with the 1756-L61 that they only publicly allow you to download the last available v20.x version (v20.019).

I'm not saying that for sure that you're encountering a bug, or if there's something wrong with your network or computer or configuration.

But if I had the chance, I would load RSLogix 5000 version 20.06 on my PC, and version 20.019 on the controller, and then re-download the program and re-burn the CF card image.

Because the CF card image includes the firmware and the user program, any time you power cycle that old image will be re-loaded.

If you're not up for that, at least get a look at the OK Led when this fault happens. In RSLogix 5000, look at the predicted memory usage and see if the controller is very close to full.

The other tests I would do is try to go online when the controller is in PROG mode, and/or connect it to an Ethernet network where it can't talk to the HMI and drives, and try to go online with it under those conditions.

 

[FireWolf71]

"Ok" led blinks red

Cleaning crew is done and i'm free to test it out.
Pulled out memory card, cycled power try to go online faults out showing no program. Better than previous fault.
Download program from laptop to plc. I am then able to go offline and back online without faults. With the battery still being dead? I am going to have to put the memory card back in though.
I'm thinking the memory card has different version that doesn't match up with laptop.

 

[Ken Roach]

That's good news that the OK light is blinking, not solid. That's a "recoverable fault", and if you were able to go online you'd be able to see it in the RSLogix 5000 processor properties applet in the "Minor Faults" tab.

When you have no CompactFlash memory card and no battery installed in a 1756-L6x controller, it will lose its user application every power cycle. Because it replaces that application with an empty one, you can still get green OK and RUN indicators after a power cycle and keyswitch cycle.

So all that suggests that your CPU is basically OK.

RSLogix 5000 (called Studio 5000 Logix Designer from v21 onwards) must have the same version of the compiler/editor loaded on your PC as is running on the controller to upload/download/go online.

I agree that the next step is to put the CF card back in. Then you can try to use things like right-clicking in RSLinx to see information about the CPU. The web page from the ENBT might also show you the version of the CPU and the user program name.

And you could try disconnecting the HMI and drives and field IO, and going online while they aren't burdening the CPU.

What you're experiencing isn't normal, but it's not unheard of for a ControlLogix of that generation to get "wrapped around the axle", so to speak, especially if it's loaded to the edge of its memory and CPU capacity.