Fluke 5020A user manual Equipment, Preparation, Calibration Points, Introduction

Calibration Procedure 7

Introduction

Introduction

5026A-x sensors used with the thermo-hygrometer should be periodically calibrated to ensure accuracy. A six-month calibration interval for the first year, and one-year thereafter, is recommended. The thermo-hygrometer display unit does not require calibration, and the sensor can be sent to a qualified service center for calibration without the thermo-hygrometer display unit. Contact a Fluke Authorized Service Center for return instructions prior to returning the probe for calibration. Ensure that the probe is packaged adequately to ensure safe transport. It is recommended that you acquire and use the optional probe case for transport.

For those who wish to perform their own calibration, the calibration procedure is outlined as follows.

Equipment

•Temperature/humidity chamber to use as a relative humidity reference and a stable- temperature environment (0.37% RH uncertainty or better is recommended)

•PRT and associated readout to use as the reference thermometer (0.03 °C uncertainty or better is recommended)

•5020A Thermo-Hygrometer to use to read the 5026A-x sensor

•An extension cable to connect with the 5026A-x sensor placed inside the temperature/humidity chamber

Preparation

Allow the 5026A-x sensor to “dry out” in air with relative humidity between 20 and 50% and temperature between 16 and 30 °C for 24 hours before calibration. Place the 5026A-x sensor inside the temperature/humidity chamber, near the center, attached to an extension cable that runs to the 5020A outside the chamber. Place the PRT inside the chamber with the tip close to the tip of the 5026A-x sensor. Run the probe cable to the outside of the chamber and connect it to the PRT readout.

Calibration Points

Each measurement parameter, both temperature and relative humidity, is calibrated at three points throughout its range with the other parameter held constant at the center of its range. The following tables list the calibration points for the two sensor models and for both measurement parameters.

Table 7-1. 5026A-S Temperature Calibration Points

Temperature	At Relative Humidity
15 °C	45%
25 °C	45%
35 °C	45%
Table 7-2. 5026A-S Relative Humidity Calibration Points
Relative Humidity	at Temperature

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