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mmd604

Modicon 984

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Posted (edited)

I have found my self in a plant with no experience with this PLC its old and I cant find much documentation. Just out of curiosity say I had a failed input output card (series 800).  Can I remove power to the processor or remote processor(J890) and have it retain its memory ? also are they any changes I would have to make in Concept programming software to see this new input/Output card. I am aware of top and bottom keying on input/output modules. Just want to be prepared so if  any thing happens which I am sure it wont I will atleast know a thing or two.  Thanks for any info

Edited by mmd604

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You do not need to kill power to replace an I/O card. You can replace it "hot".  You only need to kill power on the processor, remote I/O interfaces, power supplies etc.

The J890 gets updated from the processor on power up. nothing to reload there. Also, no programming changes for replacement card.

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Ok thanks so for example If I change a bad I/O card on remote rack and processor(J890). I can kill power to the power supply I wont risk losing memory because the memory is stored on the Master PLC ?  That being said if I was to change a bad I/O card on the Master PLC (984) just make sure my battery is good before I kill power on the power supply.  Once again thanks for any info you provide!

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That is correct. But even on the "master" rack  you do NOT need to kill power to replace an I/O card.

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Ok thanks sorry for being a pain but in the manuals it says to kill power to the power supply before pushing in i/o card that's not correct? or just a safety precaution

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Posted (edited)

Geez, a 984A, B or X?  I worked on those in the early 90s.  I remember them being "hot swappable" as long as it was a one for one replacement.  I think there were exceptions for some specialty modules.  I think I used Concept once.  This is the dark ages, we used the old Taylor MODSOFT running in a MS-DOS or WIN 3.0.  Of course, before that we have the oscilloscope suitcase for programming on a 4 inch CRT.

Edited by pcmccartney1
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Posted (edited)

Its A I believe  and to be honest it scares me haha.  That being said these things last!! 20 years no problems

Edited by mmd604

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