PLC 5/80C crash, questions!

tomalbright

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Join Date
May 2006
Location
Gonzales, LA
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We use some PLC 5/80C processors on 3 platforms. I received a call yesterday that there was an ESD, and now the PLC is "dead".

My boss has been on the phone with them, there is no tech there (I am out of state) and so far I think we're hosed. Here's what's been tried:

- PLC software can't find PLC
- can't ping PLC
- all plc lights are "looking right"

My thoughts are that the PLC took a dump. This happens, but rarely. I'm really hoping that the sidecar ethernet is just out of whack somehow. What is needed to access the PLC? I've never had one like this. Boss says there is a card you have to use on pc, that would be different.

They are talking about waiting for me to get back which could be thursday or friday, so I can't get much info. There is a non-plc tech there, and he has done "stuff" trying to get the plc back online.

Suggestions? Ideas?
 
trying to plc info from a non plc tech is like trying technical support from a guy named 'joe' that is based in india.
 
Not sure if it is possible to set the IP address via Ethernet.

This reminds me of a time that I visited a customer to fix a small problem. It was a PLC5-40E. In one of the production stops, I wanted to do the modification, but pressed the wrong button at the wrong time, and the program was cleared including the IP address. Not only was I thrown offline, but the whole plant was dead as a doornail !
I rushed to make my own serial cable, by canibalising two other cables, so that I could go online via CH0 and set the IP address. I had to remove the CPU to set the switches for RS232, connect at 1200 baud, set the IP, remove CPU to set back to RS422, connect via Ethernet, download the program adain. Phew - the customer never figured out what was happening, and they were up and running again at the planned time. Hah !

So, bring a serial DB25-DB9 cable with you, just in case.

For an 80C, you should in any case be able to access via CH0 (serial) or CH1A (DH+). Both CH0 and CH1A are set via dipswitches, so they cannot be goofed up via software. Maybe the "card you have to use on PC" is a DH+ card, so that is also an option.
 
If you need them repaired at a fast turn around time you can send them to Perfection Servo Hydraulics. They do good work over there. Pshinc.com
 
You mentioned that you have an Ethernet sidecar.


I had a 5/80 with a ethernet sidecar once that appeared to have ceased communicating. What we found was that the Ethernet sidecar faulted, but the processor was functional. No indication on the processor lights, but the ethernet sidecar lights were flashing.

Record the sequence of lights, and look at the user manual (or contact AB). This is how this module reports errors.

I believe that we had to reload the program to clear the fault. Maybe cycle power first to see if that clears it.

Hope this helps.
 
Jesper, I'm 99% sure a serial cable will work, but my boss has it in his head that we need an $1800 card. I'll use it if I have to, but all ab plcs use serial comms as far as I know.
 
I'm pretty sure I've had this happen once and I was able to clear it. Power cycling has happened. The non-plc tech has apparently removed cards to clean the connectors. Oh my what a week...

Oakley said:
You mentioned that you have an Ethernet sidecar.


I had a 5/80 with a ethernet sidecar once that appeared to have ceased communicating. What we found was that the Ethernet sidecar faulted, but the processor was functional. No indication on the processor lights, but the ethernet sidecar lights were flashing.

Record the sequence of lights, and look at the user manual (or contact AB). This is how this module reports errors.

I believe that we had to reload the program to clear the fault. Maybe cycle power first to see if that clears it.

Hope this helps.
 
tomalbright said:
I'll use it if I have to, but all ab plcs use serial comms as far as I know.
Dont be so sure about that.
"Classic" PLC5's only have DH+, and SLC5/01../02 as well as some ML only have DH485.
Sorry for being so anal.
 
Status update:

One of our (non plc but experienced) guys went out, and NOW they havwe diagnosed the lights as a "memory fault". This is remedied by a reload, which, if it keeps it, will solve the problem.

No idea how this happened. I know the ethernet module has some special tricks it can pull with diagnostics that are hard to diagnose. It might have had a full buffer or something. The plc being wiped might have come from the "other" work done last night.
 
I have seen memory loss on a PLC5/40's before. The installation UPS's cured the problem in my case.
 
A reload fixed it. We are still uncertain what happened, but with "people" working in the cabinet I think we are at a loss. I'm pretty sure it was an enet card error.

Why, who knows? I think we may need to have some education on generator switchover. The plc system is on 24V, with battery, but this platform seems to have issues...

That, and scrambling to locate a cable when somebody (non plc guy) standing by "had one in their bag".
 
The PLC5 is super reliable. I had one lose its program once, and successfully reloaded it. About a month or so later the power supply died after 12 years in a dusty tire plant.

I have seen them survive being literally filled with water while powered and survive once we dried them out and reloaded the program. This happened to five machines with 5/40s after a huge storm and roof leak. Three of the five didn't even need to be reloaded, one was reloaded (from losing its program) on the floor, and the fifth was swapped since we struggled communicating to it. I later revived it in the shop. Too bad the obsolete servo amps didn't fare so well...
 
OK, I am back at work, haven't gone to the PLC yet, but it seems there was a lightning strike...

I will be changing the battery, but that's about it.
 
It happened again. Now, I am getting a picture of events. This time, an electrician (not ours) decided to overcome the plc interlocks on the diesel generator by jumpering the breaker open. He should have waited for our PLC guy, BECAUSE, somehow the operators got a gas generator going, and voila! The diesel is now fried, and there is no backup power whatsoever.

In the process of this, the PLC, amazingly, has lost its mind again. We are thinking the ethernet or the CPU may be hosed. Our guy is out there right now, draining what's left of the batteries to load the PLC. Can you say voltage problems? Even on the 24V system? Undoubtedly something can get in somewhere, and it hurts. Badly.

Along with this, it seems that someone was a-jumpering the first time around as well. I have a sneaking suspicion that what can't be fixed is jumpered. It's not good. I will post the results of the installation effort, but right now it's by serial cable. The ethernet card had some kind of goofy error on it that would not clear, so no luck going that way. They tried an ethernet address load to get it on the network, but FAIL.

...amazing...
 

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