Some companies just need a calibration certificate and they do not care about the numbers shown and they are happy that they have a valid certificate to fulfill their obligation to ISO requirements.
How many people have encountered this kind of laboratories?
Basically the are just churning out fake certificates
It's not a rare issue at all. I'd stick with an OEM A-brand calibration lab if you can.
How many people have encountered this kind of laboratories?
Basically the are just churning out fake certificates
Then there's the lab that is underequipped and tries to get by with what they have. We'll call that the 'doing the best we can' job. This can range from questionable to downright useless. In some cases the data may be fake-ish or overly optimistic, as frequently seen in eBay sales.
Our cal lab sent a guy to our office to calibrate our stuff over the course of three days. He left his stuff in the open after he left for the day. Mainly out of curiosity, I just wanted to see what kind of cool metrology stuff they had. Didn't touch anything, but I found no evidence of an inductance standard...and we have something like 3 or 4 high accuracy LCR meters. No decade inductor either. But the LCR meters got a sticker!!
Now...maybe there was some more crates of equipment in the truck, but I don't think so. And maybe newer meters don't need an inductance standard ? I don't know...but most of the older meters put them in the calibration procedure.
Our cal lab sent a guy to our office to calibrate our stuff over the course of three days. He left his stuff in the open after he left for the day. Mainly out of curiosity, I just wanted to see what kind of cool metrology stuff they had. Didn't touch anything, but I found no evidence of an inductance standard...and we have something like 3 or 4 high accuracy LCR meters. No decade inductor either. But the LCR meters got a sticker!!
Now...maybe there was some more crates of equipment in the truck, but I don't think so. And maybe newer meters don't need an inductance standard ? I don't know...but most of the older meters put them in the calibration procedure.
I had an LCR meter here for service, being resold by a surplus dealer. After I patched it back together, I considered having it calibrated. The procedure requires an OEM calibration kit with 4 characterized resistors, an open and a short fixture and that's it. So no inductors, per se and the machine basically calibrates itself at your command.
In this case, the kit costs $4K [url]https://www.ietlabs.com/pdf/Datasheets/7000-09.pdf]https://www.ietlabs.com/pdf/Datasheets/7000-09.pdf] [url]https://www.ietlabs.com/pdf/Datasheets/7000-09.pdf [/url] and the job takes a total of 90 minutes on the bench, not including warmup and acclimatization, but only about 10 minutes of tech time. I ended up sending it out 'as-is' (it seemed to work pretty well) because the two labs I contacted couldn't answer basic questions about the process, i.e. "do you have this kit at your location". One eventually, perhaps accidentally, admitted that they would ship the unit to their "Massachusetts location", which happens to be where the OEM is. The way that thing was put together it could barely survive a car ride in my cushy SUV, let along 3000 miles of UPS.
Our cal lab sent a guy to our office to calibrate our stuff over the course of three days. He left his stuff in the open after he left for the day. Mainly out of curiosity, I just wanted to see what kind of cool metrology stuff they had. Didn't touch anything, but I found no evidence of an inductance standard...and we have something like 3 or 4 high accuracy LCR meters. No decade inductor either. But the LCR meters got a sticker!!
Now...maybe there was some more crates of equipment in the truck, but I don't think so. And maybe newer meters don't need an inductance standard ? I don't know...but most of the older meters put them in the calibration procedure.
"Calibration is the comparison of a measuring instrument, the unit under test (UUT) to an appropriate standard that is more accurate than the UUT."
In response to bdunham7 talking about needing 4k of kit, would a good Decade box not cover that, looking at the specs and procedure it looks easy enough to DIY. My portable calibrator even has a simulated resistance mode that may have worked.
Out of curiosity, I checked a few "digi-bridge" style LCR meters from the last 20-30 years. Seems they need the precision resistor set only...I guess this is acceptable because the overall topology is a Whetstone bridge?
I have an old HP 4332A LCR meter at home. It requires two standard inductors, two standard capacitors, and two standard resistors to calibrate (properly). Per my understanding, it does not use a bridge, but has a in-phase/quadrature detector, sort of like a VNA, but just for two test frequencies. Maybe that explains it.
Is bridge the prevailing LCR meter topology these days? What does the IET/ DER DE-5000 use?
Not to get too crazy off-topic here...
Into Russia metrology problems is same.
I see real/true measurements only into Keysight Moscow metrology lab and VNIIM D.I.Mendeleeva where store some of ours primary metrology standards.
Into other places metrology is fake.
After sending a long complain email to the calibration provider, i also kept their Principal in US in loop. The company admitted that something went wrong in their process and they have recalled both the unit for re-calibration. They will be barring the cost for both transportation and calibration. Lets see how it goes
Update:
After sending a long complain email to the calibration provider, i also kept their Principal in US in loop. The company admitted that something went wrong in their process and they have recalled both the unit for re-calibration. They will be barring the cost for both transportation and calibration. Lets see how it goes