SLC5/04 unable to change to PROG mode

jvdcande · Nov 18, 2008

Hello friends,

a pupil of mine is encountering a strange problem and so far I'm unable to help him out. The situation is as follows: he's on board of a dredging vessel and one of their SLC5/04s is behaving strangly. Te program is running corretcly and can be monitored. But my pupil is completely unable to switch the processor from RUN to REM or PGM, neither by means of the software or by using the keyswitch. It looks as if the mode is fixed to RUN. I have never seen this situation, nor can I find this situation in the available documentation. I'm thinking of a hardware fault in the keyswitch electronics in the CPU. Anybody here can shed some light on this situation?

Thanks in advance,

allscott · Nov 18, 2008

That's weird, anyone know what the "allow future access" check box under controller properties does?

LJBMatt · Nov 18, 2008

allscott said:
That's weird, anyone know what the "allow future access" check box under controller properties does?

That is more for write and online protection. The keyswitch masters all IIRC.

This is a Rockwell question. The version of software and firmware of the 5/04 will help. I'd say somehow in the firmware the PLC has locked itself into run mode, great unless you need to make a program change.

jvdcande · Nov 18, 2008

allscott said:
That's weird, anyone know what the "allow future access" check box under controller properties does?

Yes, I do. It's the fact that the key switch doesn't work anymore that worries me.

Kind regards,

kbpatton · Nov 18, 2008

Never heard of this happening. Like you said, I'd guess that there is a mechanical problem with the actual keyswitch. I'f a spare is available, I'd swap out the processor to simply find out if the keyswitch is the problem.

allscott · Nov 18, 2008

kbpatton said:
Never heard of this happening. Like you said, I'd guess that there is a mechanical problem with the actual keyswitch. I'f a spare is available, I'd swap out the processor to simply find out if the keyswitch is the problem.

Yes but he can't change it with the software either. If you try to change modes without the keyswitch in rem you'll get a warning something to the effect "key switch in run mode, must be in remote".

nswu1 · Nov 18, 2008

Has he tried cycling the power? If so what happened?

Ken Roach · Nov 18, 2008

If the controller was fixed in Remote Run or Remote Program and wouldn't accept a command from RSLogix 500 to change modes, I'd say you might have a firmware malfunction.

But because it's fixed in RUN, I suspect a damaged keyswitch. I've seen this happen a couple of times when the switch was left in the slot when a door containing an overstuffed document holder was jammed shut, also if the panel being built was dropped over on its face.

I wouldn't attempt to jumper around the switch; I'd get a replacement controller and load the existing program into it.

Operaghost · Nov 18, 2008

I second the broken keyswitch. I have seen this a couple times.

OG

jvdcande · Nov 19, 2008

It seems my suspicion of the keyswitch being broken will be confirmed.

For the record: the guy is using Rslogix 500 5.20 and the CPU is an SLC 5/04 1747-L542 C7 with OS401 C8.

Thanks for all the replies.

Kind regards,

JeffKiper · Nov 19, 2008

I have not done this so it is a question that I will try to do at work in the morning. Can you write to the S:1/0~4 and force the processor into run only mode? Will the processor overwrite the Keyswitch? I have a 5/05 on the wall so I will try this and get back to you in the morning.

JeffKiper · Nov 25, 2008

I said that I would try this and I did. The key switch takes control over the PLC so my idea was a NOGO

jvdcande · Nov 25, 2008

OK guys, thanks for all the help. I forwarded all info to my pupil , but to no avail. He will send the CPU back to their supplier to check it out. There was also a problem about not getting the ownership of the processor when trying to change a rung, but all info found on the site didn't help him with that one either.

Kind regards,

dmroeder · Nov 25, 2008

Is your pupil using message instructions in the program?

I've seen the logix platform prevent you from going out of run mode because of a message instruction. I don't remember the exact situation that created it. Maybe it is when the message instruction was enabled, but not done. Someone actually posted a picture of their keyswitch in program mode, but the processor was still in run mode.

This may or may not apply to the SLC format. It was just a suggestion.

SLC5/04 unable to change to PROG mode

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