The limitation to a 2 point calibration is that it assumes your transducer is performing at a theoretical (perfect) level. You have heard the saying a nature abhors a straight lines? Well, this is a very true saying, and applies to transducer performance just as much as it does to rivers and streams. Now, the effect of the lack of linearity depends on the errors due to inaccuracies and on the userâs quality requirements.
Letâs assume that the 100 LBF transducer in our example performs with a nonlinearity specification of Â±1% at half scale, and the 2 point indicator has been calibrated at 0 Lbf and 100 Lbf, when 50 Lbf is applied, the display will read 50, but the actual force is in the range of 49 to 51 Lbf. So due to the 2-point calibration, the inaccuracy of the performance curve is hidden.
So in short, the limitation of a 2 point calibration is the inability to compensate for nonlinear performing load cells, yielding inaccurate readings.
**Its important to note that a load cell will always perform within OEM specification limits when new. However, after prolonged use and age the performance will begin to degrade, and a 2 point calibration may not be able to compensate for this change.