A simple technique for automated calibration

When any sensor has been calibrated, it is desirable to compare it to the other similar sensors that are held so that new `values´ are attributed to all. Some sensors may appear less stable than others if they are affected by noise from neighbouring equipment or if they have poor isolation through their power supply to ground. The method described for automated calibration allows such difficult faults to be traced. Sensors which are particularly easy to compare are ones whose outputs are voltages. This technique is described here although sensors with a resistance or current output can be intercompared also but with more need for careful measurement repetition