[volt-nuts] Thommen Model 230 Multifunction Calibrator

[Elio Corbolante]

> How accurate is it to % or ppm?

I made some quick and dirty tests in the following conditions:
1) Solartron 7150+ not calibrated and turned on 15 minutes before
measurements
2) Thommen 230 in battery mode (no external power supply)
3) I set the output voltage in mV (entered with the following format:
xxx.xx) and I waited for the output to stabilize (from 6 to 12 seconds)
4) I used cheap tester leads to make the measurements
5) the ambient temperature was about 25 Celsius
6) I repeated several times the measures and the max difference shown on the
7150+ is no more than 2 units on the least significant digit (6 digit mode)

here it is a small table with some of the measured values (columns:
1=Thommen, 2=7150+ reading, 3=delta%):
[I padded the numbers with zeroes so I hope the formatting will not be
disrupted]

  Thommen
7150+ delta%  0000.10 0000.099 -1.010  0001.00 0000.996 -0.402  0005.00
0004.996 -0.080  0010.00 0009.997 -0.030  0020.00 0019.998 -0.010  0050.00
0050.003 0.006  0100.00 0100.011 0.011  0123.45 0123.456 0.005  0200.00
0200.020 0.010  0500.00 0500.057 0.011  0900.00 0900.067 0.007  1000.00
1000.080 0.008
I know these measurements are far from what you are used, but not being a
real Volt-Nut, I think 15 euros was a good price for this small portable
calibrator...
Now I have only to find some documents which explain me how to really use
it!!!

.    ciao
_        Elio.