SLC I/O Read Config

Christoff84

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• Dec 2, 2010

• #1

We installed a new rack today to one of our SLC 5/04 units. When we did the read IO config, it came back with some wierd settings I've never seen before. If we clear out the modules from the empty slots it faults. If we leave them in, it runs. Anyone seen this or know of it? It's a first for me.

Only slot 23 has a card in it, the rest of the slots are empty.

 

bkottaras

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• Dec 2, 2010

• #2

Did you "Clear" and download the new configuration?

 

Christoff84

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• Dec 2, 2010

• #3

Yes we did, it faults the processor for improper configuration.

 

bkottaras

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• Dec 2, 2010

• #4

Do you have an EEPROM?
Maybe the CPU gets loaded from an existing EEPROM on power up and expecting to see the "old" configuration

 

OkiePC

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• Dec 3, 2010

• #5

I've never seen an empty slot reported that way.

WAG: Could there be something mal-connected on the rack extension cable? Or is there perhaps a power drop or break somewhere along the backplane or its connectors?

 

Gil47

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• Dec 3, 2010

• #6

I could well be wrong but I feel that SLC 500 has a limit of 27 slots and your setup shows 30.

 

Ken Roach

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• Dec 3, 2010

• #7

Thirty addressable slots is the SLC standard. You can physically connect chassis that add up to more than that, but you can address only 30 with a CPU or a 1747-ASB or 1747-ACNR15.

I did find an RA Knowledgebase document suggesting that the light loading of a single module in a large expansion chassis could have an impedance effect on the backplane bus that results in it detecting those "ghost" modules.

http://rockwellautomation.custhelp.com/app/answers/detail/a_id/6209

You might have better stability with a 4-slot chassis to house that one module, or install any future planned modules now.

 

Last edited: Dec 3, 2010

Christoff84

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• Dec 3, 2010

• #8

Thanks for the reply Ken, I can't seem to see that article, says its locked even though I am logged in under my direct connect account.

I will add a few more cards to the rack and see if the errors disappear, we'll probably endup using them eventually anyway.

 

OkiePC

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• Dec 3, 2010

• #9

Christoff84 said:

Thanks for the reply Ken, I can't seem to see that article, says its locked even though I am logged in under my direct connect account.

Click to expand...

They're probably updating that technote. That has happened to me a couple of times too...They are finally updating the particular note I need to solve a problem right now!

Gosh I am spoiled. It must be a massive undertaking for the folks at RA to keep up with all the documentation they provide. I do see perceptible improvement, and I have used the feedback system and gotten excellent interaction from them.

Ken, have you had a glimpse of the new website?