We have some 200 LBF Interface Load cells which require ASTM E-74 for tension only. We're having problems with repeatibility between different vendors.
Any suggestions for an A2LA accredited calibration house with a good track record?
What do you mean with repeatability between vendors? Is it reproducability you are having trouble with? If so what are the techniques the calibration houses you have sent the load cell to using? (ie, using weights or standard load cells). My other question would be what are the uncertainties of there measurements? This is the reason I ask. I have had many problems with customers, and even my own vendors, with this problem but I have to look at it like this. I can repeat a measurement over and over again in quick succesion and get the same reading with minimal error. I can reproduce a reading over a period of time and get readings within my estimated uncertainty. My readings, I would expect will be different compared to other vendors because the testing environment is not the same but they will be within my estimated uncertainty. Are the readings your getting from your calibration houses way out there like 1.2mV/V compared to a 1.5mV/V reading? Or do the readings you get correlate to the uncertainties they have stated?
Hope this helps,
Reproducibility is the correct issue. We're finding a disparity of the scale factor >0.3%. One vendor has stated that environment is a key factor, but the difference in SF seems excessive.
Cal is per hanging weight.
if you can't do them yourself try Morehouse:
http://www.google.com/search?hl=en&pwst=1&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=morehouse+force+measurements&spell=1