CALIBRATION AND ADJUSTMENT PROCEDURE
•Calibration certifications: In addition to the normal calibration procedure, each transmitter can be supplied with its own traceable calibration certificate. Please ask Michell Instruments or your local distributor for more information.
•Calibration interval time: Under normal ambient conditions (0 to 50°C, 0 to 70% RH) and for accuracy of ±2% RH, an annual calibration is recommended. For accuracy of ±5% RH a calibration is recommended every five years. For environments with airborne chemicals or of high humidity and high temperature conditions more frequent calibration is recommended.
A humidity generator, (Rotronic HygroGen2), used in combination with a general reference handheld hygrometer, is ideal for a quick and accurate calibration. For more information on the HygroGen2 humidity generators please contact Rotronic (see www.rotronic.com for contact details).
Calibration and Adjustment
For recalibration and adjustment of the product please contact Rotronic (see www.rotronic.com for contact details).
2-wire Calibration and Adjustment (for 2% accuracy, 2pt adjustment)
1.Unscrew and remove the top metal ring from the instrument.
For the position of the potentiometers see Figure 4.
2.The transmitter should be calibrated at two points, one low point (Zero, P1) and one high point (Span, P2).
3.Once the fi rst low value is reached and the reading of the reference is stabilized, adjust the transmitter with the potentiometer P1. Compare with the reference.
The output current is set in the factory and is 5.6mA for 10% RH.
4.After the second high value is reached and stabilized, adjust the transmitter with the potentiometer P2. Compare with the reference. The output current is set in the factory and is 16.8mA for 80% RH.
5.Repeat this procedure until the unit is within the required accuracy.
6.If necessary, the temperature can be adjusted at one point with potentiometer P5.
