Before performing an adjustment, it’s important to understand the difference between calibration and adjustment:
Calibration checks the accuracy of a measurement device by comparing its readings to a known standard, but it does not alter the device. Adjustment, however, corrects deviations to align the device’s measurements with the reference standard (e.g., a Rotronic Humidity Standard). Adjustment typically follows calibration if deviations are detected.
Step-by-Step Instructions to Perform an Adjustment
1.Select the Appropriate Rotronic Humidity Standards
oIdentify the humidity range relevant to your application.
oFor example, if your measurements typically fall between 50%RH and 80%RH, use Rotronic Humidity Standards like 50%, 65%, and 80%RH for calibration.
2.Check and Adjust the Reference Value Based on Temperature
oVerify the temperature of the environment before starting.
oUse the “Meanvalue of sample at 23°C” stated in the Rotronic Humidity Standard’s calibration certificate and adjust it with the temperature factor provided on the vial packaging (see below).
oExample: If the “Meanvalue of sample at 23°C” for 35%RH is 35.21% and the temperature factor at 25°C is +0.2%RH, the adjusted reference value will be 35.41%RH.
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3.Allow Sufficient Adaptation Time
oPlace the measurement head in the sample holder with the Rotronic Humidity Standard and allow sufficient adaptation time as specified on the calibration certificate.
oFor Rotronic Humidity Standards, a minimum adaptation time of 45 minutes is required to ensure stable readings.
4.Acquire Calibration Points
oOnce the adaptation time has passed, acquire the first calibration point.
oRepeat the process for at least 2–3 calibration points using different Rotronic Humidity Standards to cover your measurement range.
5.Perform the Adjustment
oAfter acquiring the calibration points, perform the adjustment to correct the measured values to align with the reference values.
oFollow the instructions in the device manual to perform the adjustment. For devices like HygroLab or AwEasy, this can be done directly through the software interface or on the device itself.
6.Verify the Adjustment
oKeep the last Rotronic Humidity Standard in the sample holder and check the measurement head’s reading after adjustment.
oThe adjusted measurement head should now display a value very close to or identical to the reference value of the Rotronic Humidity Standard.
oFor advanced verification, devices like the HygroLab or the HygroSoft software provide features such as calibration curve overviews or show the last user adjustment details.
By following these steps, you can ensure that your measurement head is accurately adjusted and aligned with the Rotronic Humidity Standards, providing reliable and precise measurements for your application.