Prerequisites for a good measurement are:
accuracy -- precision-- repeatability -- reproducibility -- uncertainty ... and good operator skills
Optosolar delivers equipment AND measurement knowledge.
We choose very high quality components for our systems. Our analog to digital converters have a high number of bits, lowest noise, no missing codes, just as an example. We choose special resistors for measuring currents, gold coated LEMO plugs certified to more than 90.000 usage cycles, amplifiers with very low noise and very low error currents. Our plugs and cables have 'no' leakage current - you can measure down to pico Ampere, if desired.
All our measurement equipment can be certified to ISO 17025. This is necessary if the owner will use the equipment himself in a certified measurement laboratory, such as a cell testing or module testing institution.
For all other users, we offer our highly precise factory calibration. Doing the ISO 17025 calibrations for selected customers, every year, gives us a very good hold on the quality of our calibrations and their repeatability.
Just as an example: From one year to another, the calibration factor of a 20A current range changed by 0.05 % over the year (DKD calibration 2014 compared to DKD calibration 2015).
Typically, our measurement ranges are within 0.1% of the measurement value even in the lower part of the measurement range. Others give the measurement error in % of the range end, so errors tend to be large if the actual measurement value is smaller than the range end.
Typical certification result of a moduletester measurement system:
Measurement range | 'True', certified value | measured with Optosolar moduletester | calibration difference between Optosolar and ISO 17025 |
30 mV | 15,000mV | 15.010mV | 0.066% |
30 mV | 25,000mV | 25.001mV | 0.004% |
50 V | 30,000V | 30,006V | 0.02% |
50 V | 48,000V | 48,010V | 0.02% |
2A | 1,0000A | 1.0000A | 0% |
2A | 2,0000A | 2.0003A | 0.015% |
8A | 5,000A | 5.000A | 0% |
8A | 8.000A | 7.999A | 0.012% |
In this comparison of our measurement results and a certification done in 2015, all measurement ranges are substantially better than 0.1% of the measured value.
We deliver the same quality of equipment and precision for celltesters and spectral response systems.