PLC 5/80C crash, questions!

[Oakley]

If your program was lost in these events, then you will not be able to ping or go online through ethernet.

You would have to go online via DH+ or RS232 and download the ethernet configuration.

 

[tomalbright]

That's what is happening. We tried loading the ethernet address, but it didn't take. Serial port load on dead batteries is where it's at...

...at least they waited until I went home this time.

 

[OkiePC]

I would highly recommend a CVT with isolation for you PLC power source, and a surge protecting UPS after that. Those CPUs are too expensive not to spend on protection.

We had similar issues with voltage problems which were cured by Sola CVT transformers. We didn't need surge protection just ability to tolerate up to an hour or two of input voltages of around 500vac for a 480 to 120 volt intended circuit.

Our ISSC controllers were dropping like flies, but we put them on all the PLC5 controlled machines too.

Our voltage problem was due to having to manually switch capacitor banks in and out depending on demand. Every shutdown and startup we had temporary voltage issues, always to the plus side though, rarely a brownout.

We usually remembered when we got a rash of alarms for DC Bus overvoltage on our AC Drives or servos.

Those PLC5/40s lasted over ten years without a single CPU issue. The one I saw fail had a bad power supply...

You will need something in place before you upgrade, but just controlling the PLC power supply voltage will probably render the beast cured and faultless for a very cost effective mid-term fix.

Good luck reviving it. I had to rescue a litter of drowned PLC5/40s once, but they all had at least one channel I could access them through. You just have to try them all.

I would recommend you perform a CLEAR MEMORY once you get connected, and in program mode, then try to download the whole program. After that, test all your comms and racks...

Good Luck!
Paul

 

[tomalbright]

Yes, I suggested the Clear Memory for them to use, seem to have missed that.

As far as power control, these platforms run off of 24V, there's a huge bank of batteries, charged off a table sized Ratelco charger. Generators are on 480V, stepped down through one transformer to 240/120. The voltage situation isn't one that changes. Ever. Tieing together two non-compatible generators is interlocked by PLC and electrical components. It never happens. Unless you jumper it, which is WRONG.

We might need a bigger UPS for our PCs, they don't last too long. As far as the remainder of the system, it's ok. Keep in mind that this platform was installed in about 2002, and until recently this particular problem has been non-existent. We won't discuss the personnel changes, but there's a real question about this which my boss and I are discussing.

 

[tomalbright]

It's up. When the rental generator showed up, everything magically appeared as normal. No program errors, nothing wrong except an ethernet fault. I have a BIG disadvantage in not being there to see it, but apparently there was a problem setting the ethernet address, as in, it would return an address of "0.0.0.0". On getting power back on, the normal address magically appeared. I think it has to do with how the PLC5 and the sidecar module share the program info, but no idea.

According to my boss, it acted like there was an EPROM in it when power was restored, but didn't do that before. Confusing. The DC power is totally separate from the mains, it really doesn't make any sense. It might have been a low voltage problem, using the dead batteries as power. Might not have gotten enough DC + to the PLC. I'm thinking in the 20 V and under range.

Weird. Oh, and no one apparently told the bosses the generator was toast for about 4 hours - we did, apparently. It won't be pretty today at their safety meeting.