SLC 500 CPU Fault

whiggins · May 2, 2006

Hello, I have a cpu fault (blinking light) on a 1747 L20A processor. I can not go online with the processor to clear the fault. When I power down the proc. it doesn't clear the fault. Can not find a batter to pull to clear the fault. What else am I missing? Thanks, whiggins

Keldog · May 2, 2006

Try on the back on the processor there should be VCC and GND take a flat screwdriver and put it across both for 60 seconds, that should reset the processor.

They will look like sodered connections.

davidg68124 · May 2, 2006

Won't that eerase the program? I think it will. Sure you will reset the processor, but then you have no program. Is this what you want?

David

Keldog · May 2, 2006

Yeah it sets the SLC back to factory defaults. So it would be a matter of uploading the program back into the SLC.

OkiePC · May 2, 2006

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1747-um009_-en-p.pdf

See page 96. That sucker is a little different that the SLC modular style I am used to.

whiggins · May 2, 2006

whiggins said:
Hello, I have a cpu fault (blinking light) on a 1747 L20A processor. I can not go online with the processor to clear the fault. When I power down the proc. it doesn't clear the fault. Can not find a batter to pull to clear the fault. What else am I missing? Thanks, whiggins

I can not find the VCC/ Gnd connections. Do you have to take the sides off to get to them or is it on the bottom? Are they marked very well????

Keldog · May 2, 2006

Download the manual posted by OkiePC. This is a differnt controller then what i figured so there is probably no VCC or GND. I'm sure the manual will tell you how to do a reset on the processor. On page 96 it has a nice trouble shooting guide.

whiggins · May 2, 2006

My fault is more like on page 97. I have a flashing cpu fault. The book says to look at the status files to clear the fault. Well I can't go online because of the fault???I am not worried about losing the program or memory.

Keldog · May 2, 2006

1.

Remove hardware/software condition causing fault.

2. Clear Status File S:1/13 major error bit, if set.

3. Clear Status File S:5 minor error bits, if set.

4.

Clear Status File S:6 major error code (optional).

5. Attempt a processor Run mode entry.

Remove all the cards from the Rack. Clear these bits in the program while offline then try to download the program back in to see what you get.

504bloke · May 2, 2006

whiggins said:
My fault is more like on page 97. I have a flashing cpu fault. The book says to look at the status files to clear the fault. Well I can't go online because of the fault???I am not worried about losing the program or memory.

You should be able to go online with the processor fault light blinking, unless the processor or comms are dead!

How are you attempting to go online ?

PIC? RsLinx Autoconfigure ?

You probably have a processor that has a flat battery and the unit has losts its program, even if the battery low light is not up, if its old and there were a few power outages then this could be the case as i have had it happen to me before. But like i said you should still be able to go online.

504bloke · May 2, 2006

whiggins said:
I can not find the VCC/ Gnd connections. Do you have to take the sides off to get to them or is it on the bottom? Are they marked very well????

It hasnt got those connections, that advice is for the 5/01,02,03,04 and 05 modular slc series.

whiggins · May 8, 2006

Hello I have the PIC box. I tried to go online with this processor with another computer/ pic box and the following dialog box came up:
Default program loaded due to NVRAM error. A corrupt CRC was detedted (loss of battery power may cause this), or a power cycle in the middle of a user program download, initialize memory or memory module load.

I hit OK. Says can not go online from default processor (no Program)You must perform a down load.

Where do I find the battery on a 1747-L20A. I have looked every where... I am going to try a download and I will get back to you.

whiggins · May 8, 2006

Hello, I just did a download and the fault cleared. I still do not know where the battery is???? Why can't they be where they are on the PLC 2, and 5's????? guess that was toooo convenient. Thanks a lot for your help.
Mark H

mgvol · May 8, 2006

See attached for battery location/replacement. The fixed hardware style user manual can be found here:
http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1747-um009_-en-p.pdf

504bloke · May 8, 2006

whiggins said:
Hello, I just did a download and the fault cleared. I still do not know where the battery is???? Why can't they be where they are on the PLC 2, and 5's????? guess that was toooo convenient. Thanks a lot for your help.
Mark H

The slc 500's are loike a brick shape, the top and bottom terminals have covers over them, from memory the battery (and eeprom or uvprom) is on the left hand side under a cover about 2" square, it hinges out from the left.

SLC 500 CPU Fault

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