No program after power interuption

Hello all,

I'm new here, so bare with me please. I have a SLC 5/04 processor that seems to lose it's program every weekend when we shut down. The battery has been changed, and we even changed the processor. It doesn't have an EEPROM. Today they wasn't running this piece of equipment all day so I had some time to play with it a little. I cleared the memory from the processor. Then downloaded the program again. I went online and all seemed ok. Then I shut down everything on my laptop. And went to go back online with the processor. I went through and configured my driver in RSLinx, but when I went to RSWho my PLC was named something different than the program I just downloaded to it. When I tried going online I have to browse to find the program. But when I do it comes right up and goes online. I didn't have time to check to see what would happen after the power was cycled again, but I'm not getting a really warm feeling about it. Where I worked for the past 7 years or so every PLC was on a server and I'm not really up on plugging in directly and and getting everything set up. Please help.

Try changing out the power supply on the chassis. That is what fixed my issue.

+1 for the power supply that is always a good place to start.
When you shut down do you open the local breaker/fuse for the power going to PLC? I have seen "Shut Downs" where the main breaker for the area or plant is tripped. That can cause power spikes that cause major issues with electronics. You may want to double check your procedure to make sure that you shut off all the electronics first one at a time first, then do a major shut down. Do just the opposite when you power back up.

Welcome to the Forum !

Have you been able to see the LED states on the controller when it undergoes this failure ?

Does the controller appear with the controller name "DEFAULT" in a DH+ browse after this failure ?

Have you tried to go online with the controller to read the fault code after one of these failures ?

Remember that the Program Name that shows up in the RSWho network browse is part of the Controller Properties, and is not necessarily the same as the name of the *.RSS file.

There is a comprehensive list of possible grounding and power spike issues and remedies that can cause SLC-5/0x controllers to clear their user control program in RA Knowledgebase Article ID 15763 (TechConnect required).

It's possible that you've got a bad power supply, but don't jump to that conclusion without looking at the measurable symptoms like the fault code.

Ken,

The fault light will come on when the power is returned. I can't go online with the processor to see what the fault is. I have to download the program. before I can go online. And after I download the program the fault is no longer there. And yes I'm sure the way the power is turned off could be better. I think they Estop the machine then throw the 480 disconnect. But, I know if I bring this up I will be told that's how we've always done it and that's how we do it on all the other machines and they don't have the same problem.

Sounds like you just have a bad 5/04, try changing it... odds are you got a spike in the line voltage for powering down/up but the 5/04's are cheap enough, just get a used one if you dont have one and swap it out, I dont think throwing a main when powering down is that big of a deal, when they hit the e-stop that should be killing the control voltage so the next step would be the disconnect

We can fix them (the CPU) and we also sell them, they have a lot of electronics on them so cycling power, lightning and static spikes are the killer most of the time

If there is a UPS on this piece of equipment you might want to check it prior to replacing hardware. I have seen a couple instances where a cheap UPS was used, as power was drained from the UPS the OUTPUT voltage got lower causing a low voltage at the PLC. This low voltage can causes all kinds of problems, it seems to affect the SLC and PhxCon Radio's consistently based on my experience.

The fault light will come on when the power is returned.

Click to expand...

Solid red or flashing red ?

A solid red LED indicates an unrecoverable fault, while a flashing red LED indicates a recoverable fault and that there will be a readable fault code in the controller.

I agree that a solid red LED after a power cycle suggests that there is a power spike corrupting the controller memory. It could be a problem with the SLC power supply (1747-P_) or something unusual about the power distribution on that particular machine.

Replace the PLC Power Supply.
I have dealt with this exact issue on SLC500
Power supply appears to work but is weak or flaky which will wipe the program on a power interruption or dip.

Thanks guys. I got a spare rack out today and downloaded the program to it in the office. After testing it many times I felt like all was going well. So I proceeded to take the CPU down to the machine. I installed it and then cycled power..... Back to square one. This time my laptop wouldn't communicate with the plc. I couldn't get the driver to configure either. I restarted Linx, still nothing. So I replaced the power supply, put the original processor back in, said a prayer and turned power back on. What do you know everything is working now. I cycled power several times and everything came up like it was supposed to every time. Praise The Lord! After looking at the power supply I saw a burned spot around a resistor. So I guess that was the problem all along. I thank all of you so much for your help. I'm sure I will be around here again asking questions now that I know about this site.

Glad you got it and thanks for coming back and letting us know the issue... looks like my WAG was wrong but a few others had it correct, I will need to remember this one, I would of lost money on a bet, sounded like a processor issue to me