Campbell HC2S3 Instrukcja Obsługi Pobierz pdf (Strona 22)

Model HC2S3 Temperature and Relative Humidity Probe

3. Verify the green power wire is connected to the 12V, SW12V, or 5V

terminal. When SW12V is used with a CR10X datalogger, verify the

SW 12V CTRL is jumpered to the Control Port specified in the program.

Cables longer than 3 m (10') should be powered by the 12V, rather than

the 5V terminal.

A voltmeter can be used to check the output voltage for temperature and

relative humidity on the brown and white wires respectively (temperature

°C = mV * 0.1 – 40.0; relative humidity % = mV * 0.1).

Symptom: Incorrect temperature or relative humidity

1. Verify the multiplier and offset parameters are correct for the desired

units (Table 5-1) and temperature range.

2. Default settings are listed in Appendix A, which include the setting

“Limit humidity output to 100%”. This setting is “disabled” for probes

purchased through CSI. Accuracy of the humidity measurement over

temperature is shown in the graph in Section 2.2. For example, at -20°C

the accuracy is ±2.3%, so a reading of 102.3% at 100% humidity is within

the accuracy specification. Programs created by Short Cut set humidity

values >100% and <103% to 100%. Humidity values >103% are left

unchanged to indicate a problem with the probe or measurement.

9. References

Goff, J. A. and S. Gratch, 1946: Low-pressure properties of water from -160°

to 212°F, Trans. Amer. Soc. Heat. Vent. Eng., 51, 125-164.

Lowe, P. R., 1977: An approximating polynomial for the computation of

saturation vapor pressure, J. Appl. Meteor., 16, 100-103.

Weiss, A., 1977: Algorithms for the calculation of moist air properties on a

hand calculator, Amer. Soc. Ag. Eng., 20, 1133-1136.

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