# Recerting PLC's



## triden (Jun 13, 2012)

I was just asked to 'recertify' some SLC 5 PLC's. They want the processor and I/O cards all checked and proven. I'm curious what kind of tests that you guys may come up with to do this. I have some ideas in my head, but it never hurts to ask to see what you guys may think. :thumbup:


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## Black Dog (Oct 16, 2011)

triden said:


> I was just asked to 'recertify' some SLC 5 PLC's. They want the processor and I/O cards all checked and proven. I'm curious what kind of tests that you guys may come up with to do this. I have some ideas in my head, but it never hurts to ask to see what you guys may think. :thumbup:


Let's hear it..:thumbup:


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## Cow (Jan 16, 2008)

You might have better luck asking the guys on the plctalk forum.


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## JRaef (Mar 23, 2009)

"Certifying" a PLC is a vague term that I would not quote on without VERY detailed specifications as to EXACTLY what they are looking for. For example if this system has _anything _to do with the military or the pharmaceutical industries, "certifying" an old SLC-500 PLC could be incredibly time consuming or might even be nearly impossible, and may include certifying or "validating" the program itself. There are companies that make a living doing nothing by that.

Example: http://prosysfill.com/technology/validation-certification-technology


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## triden (Jun 13, 2012)

We don't have to worry about these going into critical systems. The client would like to source surplus equipment for some sewage lift stations where we would ensure that all devices conform to manufacturer specifications. Some tests would involve testing the processor and I/O in its specified temperature ranges, writing routines to check I/O and communication functionality, etc.


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## KennyW (Aug 31, 2013)

JRaef said:


> "Certifying" a PLC is a vague term that I would not quote on without VERY detailed specifications as to EXACTLY what they are looking for. For example if this system has _anything _to do with the military or the pharmaceutical industries, "certifying" an old SLC-500 PLC could be incredibly time consuming or might even be nearly impossible, and may include certifying or "validating" the program itself. There are companies that make a living doing nothing by that.
> 
> Example: http://prosysfill.com/technology/validation-certification-technology


Agree, sounds like they want the OP to imply some kind of warrantee, like a "certified, preowned" PLC module. Sounds like a nightmare. Also, especially SLC IO cards are still pretty cheap, honestly it's not really worth the labor to spend much time on such a task, IMO. If they have any issues they will probably be flaky and intermittent anyways. I dunno..


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## oliquir (Jan 13, 2011)

i would just test input outputs. if output card are relay type than change the card, relays may have some wear.


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## bill39 (Sep 4, 2009)

Either have your customer provide you with a VERY detailed spec on what they want or you need to write a VERY detailed proposal and TELL them what you are going to do.


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## macmikeman (Jan 23, 2007)

Don't forget to check for stuxnet virus on it while you are at it...............


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## retiredsparktech (Mar 8, 2011)

macmikeman said:


> Don't forget to check for stuxnet virus on it while you are at it...............


 The firm I worked had ISO 9000 certification. That was the biggest bunch of BS, I ever seen.
The dame that came in to audit the records quarterly, was one of the most ornary b*tches, I ever worked with.


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## bill39 (Sep 4, 2009)

retiredsparktech said:


> The firm I worked had ISO 9000 certification. That was the biggest bunch of BS, I ever seen.
> The dame that came in to audit the records quarterly, was one of the most ornary b*tches, I ever worked with.


With ISO9000, QS9000, etc. your product does not need to work, you just have to prove that you are making it the same way each and every time. Think concrete life jackets.


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## Batfink (Jul 9, 2014)

I would ask them to change their wording from recertify to test and make up a form explaining what tests are being performed and if you warranty your work or not. We have bench tested many PLC's with basic programs we load in to check the I/O, communications etc. We have the customer sign off that they understand that products are being bench tested only and no warranty or guarantee on our part will take place. 

If that is not good enough for them I would send them off to PLC center (Radwell) to see if they will do the "re-certification" then mark up their costs 15-20 percent to pass on to the customer.


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## sparkywannabee (Jan 29, 2013)

macmikeman said:


> Don't forget to check for stuxnet virus on it while you are at it...............


stuxnet targeted Siemens, S7 I believe. OP should try to sell them upgrade, AB makes software that rewrites PLC5 software to Controllogix.


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## triden (Jun 13, 2012)

sparkywannabee said:


> stuxnet targeted Siemens, S7 I believe. OP should try to sell them upgrade, AB makes software that rewrites PLC5 software to Controllogix.


The upgrade is coming next year, this is temporary. I'm replacing with an M340.


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## chrisfnl (Sep 13, 2010)

Is this a used part they have in inventory or are they looking to source parts for legacy equipment?

If they're looking to source parts, just buy from a reputable surplus dealer.

You'd be amazed (Or maybe you wouldn't) what you can find available as new surplus... 

I've never had a problem with http://www.plccenter.ca/

We've ordered a variety of new-surplus and used-surplus parts from them for 1980s era equipment.


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## triden (Jun 13, 2012)

They are looking to source parts for legacy equipment (a bunch of SLC 5 02 and 03 PLC's).

I bought a bunch of spares, put them on a test bench, tested all I/O and slapped a 90 day warranty on it. They were happy, we were happy, and they should be fine until the M340 swap next year. I don't think they have used a spare card in the 20 years it has been running, so I can't see them using one now. They felt it necessary to have some backups though.


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## triden (Jun 13, 2012)

There, 90 day warranty.


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