A rack data error is detected. Check slot 8. 850H

[averellen]

I know this has come up before. I'm not asking for assistance. Well ok, if you have something else to add you are more then welcome
Here is my setup.
I have 9 machines all pretty much the same. Give or take an IO card.
SLC5/04 on a 10 Slot Rack.
First 5 slots are IB16's or OB16's
Last 4 slots are OW16's, with a free spot or two.

All machines ran fine for months, then 4 of them started getting this error. After searching this forum, and goggling.
I move the OW16 from slot 8 to slot 7.
Problem went away.

This week another machine started getting the same error.
I did the same, fortunately the machine builder didn't use slot 7. I move the OW16 from slot 8 to slot 7.
Problem went away.

Could this be a problem with the 10 slot rack. Slot 8's data path is real close to the relays on the OW16.
Oh and I should mention, there is no real load on relays 7 and 8 (to my understanding are directly beside the data path).
On these relays I have Numatics Soleniods. Could it be an issue with this. dunno.

I didn't get into changing output connections on the OW16. I guess I just got lucky.


Adam

 

[Lancie1]

Adam,

Yes, it could be that you have some bad connectors on those 10-slot racks. I have seen a little lint or dirt in the backplane connectors also cause this kind of problem. It may be that removing the cards and reseating them would also have solved the problems.

 

[rsdoran]

Does the panel the plcs are in vibrate from machine action? Years ago I ran into a similar problem where the system would have a problem/error and I could just remove and reseat the card and all was well. We eventually relocated the plc on the wall instead of the machine.

 

[Thomas Sullens]

We have an Ultra torch that about once a year gives a fault and we reset the i/o cards. Unplug them and then plug them back in and everything goes back to work. I believe it`s a 10 slot rack also. I believe this was the first thing tech support said to try. May just be coincidence, i`ll check in the morning if i get a chance and see if it is a 10 slot rack.

 

[averellen]

Thanks for the posts.
I had initally tried pulling the card, checked for debris and inserted again. Problem would come back in a day or so.
Like I said in a previous post, moving the relay card to the slot previous (moved card from slot 8 to slot 7) the current slot seems to have solved the problem.
Its funny that all machines are from one manufacturer. Could be a lot problem with this rack. I thought about calling AB. But have had little success with them. We do not have a support contract with them.
As long as the problem is gone, I'm happy.
The problem might not be with the racks, but with the relay cards and some kind of noise onto the backplane. Not that I'm switching a high current load.

Adam

 

[Thomas Sullens]

The maintenance manager said it was slot 7 that gave the fault. The first time he reset the card, but the last times he only reset the fault with his laptop. Sounds like ab may have a problem?

 

[Thomas Sullens]

Interesting

We are installing a new Alltra CNC plasma torch and the plc is the same as in the old torch, but slot 7 is not used on the new torch. Both use 10 slot racks! 0 thru 9 is used with slot 7 skipped.

 

[averellen]

Funny, I am getting the same error again after moving the OW16 from slot8 to slot7.
The funny thing is, everything was fine for what? 2 months.
Maybe if I move it back to slot8 it will got for another 2 months.
I tired replacing the Rack this time. Still does it, same frequency.

Man o man, I'm banging my head against the wall on this one.
Why can't whatever device just give it up and let me know exactly what the problem is, or at least a better idea.
Ah but if life were that easy would it be as fun?

Adam

 

[Ken Roach]

Noise Spikes

Virtually every time I've seen a rack fault error in association with SLC output cards, the problem has been inductive spikes coming from unsuppressed inductive outputs like solenoid valves. Even small solenoids with "virtually no load" can generate very high spike voltages when they release.

SLC-500 and MicroLogix user manuals have contained a section on output load spike suppression for over a decade, but it's the most commonly ignored installation recommendation.

If the error code is showing up for a slot that is not used, that's even more indicative of a noise problem. If the spike is large enough, the SLC backplane chip's address lines can't figure out which slot it was in.

 

[averellen]

We got a hold of a scope and connected to the 24V power to the OW16 card. This power controlled via AB relay, Via light curtain. On the scope the amount of noise when the light curtain was enter was amazing. We are starting with surpressing these relays and going from there.

Adam

 

[averellen]

Anyone have part numbers for surpressors that aren't AB.
The two devices I want to surpress are.
I know I need a diode and rectifier. Any electronic shop should have what I need.

700DC-P400Z24
700-P800A1

Adam

 

[averellen]

Solution to the problem.
There is a problem with the Series C OW16 cards manufactured between a certain date. I never got told the date range.
Anyway Rockwell replaced all 50 of my cards with Series D. Not one problem since.
It was tough to get there, I happened to be receiving a number of machines from another equipment builder. I mentioned the problem to him, and he told me about the recall. It took some effort with our distributor to talk to Rockwell.

Adam

 

[Clay B.]

Virtually every time I've seen a rack fault error in association with SLC output cards, the problem has been inductive spikes coming from unsuppressed inductive outputs like solenoid valves. Even small solenoids with "virtually no load" can generate very high spike voltages when they release.

SLC-500 and MicroLogix user manuals have contained a section on output load spike suppression for over a decade, but it's the most commonly ignored installation recommendation.

If the error code is showing up for a slot that is not used, that's even more indicative of a noise problem. If the spike is large enough, the SLC backplane chip's address lines can't figure out which slot it was in.

This kind of problem is more evendent with 24 vdc coils than AC. It was explained to me once why this is but I forget. (to many beers between now and then). I just remeber that it is an issue so whenever I buy plugs for my solenoids I get the ones with supressors built in. Most also come with a indicating LED so the mechanics like them.

This kind of noise is a killer on any PLC

 

[ChuckM]

I've had this problem in the past and it was also noise from a solenoid on one of my output cards. I wrote the output image of my output cards to integers to see what outputs were true when the processor faulted. This narrowed down the solenoid that was the culprit.

One thing that seems odd though is I've had this happen on several 10 slot racks and never got rid of the problem until I replaced the rack. I can't recall ever seeing it on any of my 7 or 10 slot racks.

 

[allscott]

I had a similar situation when replacing a 7 slot rack with a 10 slot. The 7 slot ran for years without a problem, we put in a 10 slot to add additional I/O and started seeing this problem.

Not knowing what to do I pulled the rack, ground the paint off of the backplane where it was mounted and grounded the snot out of everything (per AB recommendations). Problem went away??

I've worked in plants with dozens of SLC's for years. My gut feeling is that they are picky about power and grounding. If you take care of those two things the "goofy" problems go away.

50 new cards, wow not bad customer support