Calibration done to 1-year standard - is this standard practice?

[JuiceKing]

Hi,

I sent in a DMM for calibration and got it back with a report that indicated that nothing was done; it was in tolerance as received for every range of every function.

Great--that means it's correct and stable. But when I look closely at the report, I can see that tolerance was determined by the instrument's 1-year accuracy rating, which is the least demanding standard. It's not in tolerance for the 1-day standard.

Is this normal practice or should I call the cal lab and complain?

Thanks,

- Ken

[theatrus]

It depends on what you paid for, in a way. Its common for calibration to be done at a one year cycle, so one year specs are looked at.

For instance, I recently had a 3458A recalibrated. I had not been calibrated (at least by Agilent) for 10 years. It was in spec when it was received, though it was re-calibrated.

[saturation]

A properly calibrated device should be in factory spec and that means all specs in the manual: 24hrs, 90 days, 6 mo, 1, 2 year etc.

If your 24 hours is off, IMHO it was not done correctly. 

Calibration however only means 'measurement', not adjustment.  Some labs will just measure items and return the device to you; but it should highlight what is in and out of spec on the report.  Its then up to you to decide if you want it adjusted, but IIRC good labs inform you or its specified in the contract for an option to be notified that adjustment is required or it would automatically go into adjustment, as it means an extra charge.

Hi,

I sent in a DMM for calibration and got it back with a report that indicated that nothing was done; it was in tolerance as received for every range of every function.

Great--that means it's correct and stable. But when I look closely at the report, I can see that tolerance was determined by the instrument's 1-year accuracy rating, which is the least demanding standard. It's not in tolerance for the 1-day standard.

Is this normal practice or should I call the cal lab and complain?

Thanks,

- Ken