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Uncertainty Values

Former Member
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Hi there, 

I was wondering if anyone has had experience in maintaining uncertainty values in SAP QM? The company I work for in trying to incorporate a laboratory which is ISO17025 certified and a requirement for the transfer to SAP is to maintain a uncertainty value (+/-  x%) against test results. These calculations could be simple or very complex depending on the product and characteristic.

The requirement would be to have these visible within the results recording/inspection lot.

Please if anyone has come across these requirements and a solution I would love to hear how you accomplished this.

Thank you,

Kim

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Answers (2)

Answers (2)

former_member42743
Active Contributor
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I think what you want to do is a very ambitious undertaking.  I had to read up a bit on "Uncertainity".

This is an older docment but seemed to give a decent overview of uncertainity.

https://www.wmo.int/pages/prog/gcos/documents/gruanmanuals/UK_NPL/mgpg11.pdf

If that document is on point, it seems to me that uncertainity is determined by a number of things.  Not necessarily just statiscal measures such as Std Dev.  Which seems to be accurate since you said the calculations  "could be simple or very complex depending on the product and characteristic"

So, one thing to ask is there anyway to provide a "historical" uncertainty value as opposed to a dynamic one that is calculate for every insp. lot.  If so, a historica value, (maybe updated every 6 months or yearly), could be maintained in the Info fied 1, 2 or 3 for the master inspection characteristic.  This migh only work if the uncertainty can be test specific and not material/test specific.

If the historical uncertainty can be used, you could add linked general charcteristics and maybe add the characteristics into the 001 material class and store the uncertainity there.  Then on say the COA, you report the MIC value, and the next characteristic would be the 001 characteristic value which would be the uncertainty value.  In the COA profile, change the characteristic description for alt the 001 characteristics to something like "Historical Uncertainity for above test".

If a historical value can't be used and it must be dynamic, that's going to be much harder depending on the formulas.  So the first question is where to house the formula for each product/characteristic combination.  You can't hosue it on the characteristic as it might change given the material.  You'll probably need a Z table for it of some sort.

Then can all the inputs even be derived from SAP?  And how are they determined or stored?

Once you have that resolved, then I would probably suggest a follow-up action to the inspection lot.    I don't think I would do any uncertainity calculations in the inspection lot itself.  I would use the follow action to run a program that would look up the formula from the Z-table, then collect all the data needed to calculate the uncertainty value, then populate that result into a batch characteristic on the batch record.  I think in the Z-table, in addition to the formula, I would store the characteristic name that the uncertainity value would be reported into.

If you need to do this as a MIC in a lot, you can use the same process but instead of a follow-up action, use calcuated characteristics for the uncertainity values.  Create a FM to be used in the formula.  The formula would be simple, like Z010010 or Z010040 where the last four digits are the characteristic  you are calculating uncertainty for. Now you look that up in the Z-table like above, and return the value to the calculated characteristic.

None of this will be easy!

Have fun!!!

Craig

busyaban7
Active Contributor
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Hi Kim,

Not very sure with your inputs, but it seems "Formula Managed Characteristic' may help you.

You can try recording results for MIC1 outside sap and send the same result back to SAP in MIC1. Then there should be another MIC2 in the results, linked to Formula Parameter like (+/- x%). Ideally, MIC2 would be the one, which your business may be expecting to validate.

You can check one thread below to get some clues on how to use it -

http://scn.sap.com/thread/3684834

If result recording for MIC1 are performed outside SAP, then please check if additional calculation for "uncertainty" (+/- x%) can also be done outside SAP. If so, the it will be a bit simpler process to transfer the results back to SAP through LiMS system, and the value can be directly passed on to MIC1.

You can also wait for some further expert advice on this topic.

Thanks,

Arijit