AB PLC5/80B RIO Flex IO Fault

corkers

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Join Date
Jan 2004
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Hey Everyone,

I have an AB PLC 5/80B processor that has a comms fault on Rack 14 which is a Flex ASB adapter the module has a flashing green light "ACTIVE" all the other racks have a solid ACTIVE light. I have checked the channel status file and it has a F fault indicted in RSLogix 5. S:32L word shows a 1 against rack 14. I have taken the following action...

Replace the ASB with a known good one
Replaced an analogue input module in the rack
Tried to clear the fault on the channel status page
Tried to reset the fault with the ASB's reset button.
1
Any help would be appreciated

Andrew
 
I see your confusion given what the Flex I/O manual says about that light pattern.
It's been a while since I've had to deal wioth Flex I/O on Remote I/O. But the two things that stick in my mind are:

1) Does the configured rack size in you scan table match the switch settings on the adapter?

2) Is the rack inhibit bit set in the processor status file for that rack?

I know it's not much help but that's about all that comes to mind.

Good luck.
Keith
 
Is this something that has developed? i.e. it used to work but now it doesn't. Or has this adapter (or another) just been added?

Is the adapter in the channel's scan list?

I ran into some issues a couple of years ago with RIO Flex using 32-point modules and trying to configure partial racks.
 
Keith & Gerry thanks for your help. You know how problem grow well this turned into a ripper...

This PLC controls a spraybooth that is responsable for spraying units with clearcoat after they have been painted the required colour. This facility is also used to spray white... can you see where this is going...

Red car + white paint on half the car = expensive mistake times this by 30 cars someones getting an arse whoopin...

In maints effort to rectify the issue an old program was reloaded into the PLC.

I arrived on site at breakdown + 4.5hrs (not bad at $6K per min).

Anyway once I got that sorted OT ran for 4 hours (gave me time to find the manuals on AB website it gets harder each time). Psyched myself up fo a problem solving frenzy, finally finished production and thought OK power cycle the Rack and PLC... problem fixed (sort of) replace 1 x 1794-IE8, 2 x 1794-OE4, 1 x 1794-IB16 solved. Wierd error and didn't have the time to identify the actual fault, suspect the 1794-IE8 but inconclusive.
 
I am guessing that the switch S2-1 (outputs holds last state) in the ASB module is set to OFF, which means Hold last state when comms are lost.
That because the error didnt cause the spraying to turn OFF (not so bad), but to continue (does that mean that there are special offers on Holden's at the moment ?).
Turn that switch ON to turn outputs OFF at comm error.

Have no idea why you had comms problems.
 
Six grand a minute and they don't have printed manuals ? Good thing you have frenzy-mode.

In my experience, RIO problems with FLEX come from two sources; loose or frayed blue/clear wires at the adapter plug, and bent pins in the FLEX backplane. Both require good glasses, a strong flashlight, and sometimes a dentist's mirror to inspect (usually while inside a manhole access or atop a crane).

Even if you don't think there could possibly be a problem with those physical interconnections, usually there has been somebody (or something; water, solvent, metal chips) messing around inside the panel who won't admit it.

If you have a spare PLC-5 around, I'd connect up and attempt a RIO autoconfiguration. If it doesn't find the right rack size, then you know where to look for a bad module or a bad interconnection. I don't think there is any way to tell a rack size mismatch from any other kind of RIO fault on the PLC side.

I wonder if SST's RIO analyzer would help in this kind of application ? Anyone on the Forum using that kind of tool ?
 
Jesper,

Wrong manufacturer but am impressed with your aussie knowledge...

Ken the really strange thing was I was told (I don't believe anything I haven't personally seen as a matter of course) that an autoconfig they ran correnty id'd the rack as a half rack.

If I find anything more out about this Ill post it.

C
 
Jesper,

No that switch wasn't set, the units being sprayed the wrong colour was due to an old program being (intentionally) uploaded to the PLC, by a very fatigued electrican who neglected to think of the effect it would have as the data tables hold the info of which colours are in which paintlines...

C
 

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