Vaisala HUMICAP HMP41 Spécifications télécharger pdf (Page 20)

Model HMP45C Temperature and Relative Humidity Probe

TABLE 8-1. Chemical Tolerances of HMP45C

Chemical Concentration (PPM)

Organic solvents 1000 to 10,000

Aggressive chemicals

(e.g. SO

, H

HCl, Cl

, etc.)

1 to 10

Weak Acids 100 to 1000

Bases 10,000 to 100,000

Recalibrate the HMP45C annually. Obtain an RMA number before returning

the HMP45C to Campbell Scientific for recalibration.

9. Troubleshooting

Symptom: -9999, NAN, -40 deg C, or 0 % relative humidity

1. Check that the sensor is wired to the correct excitation and analog input

channels as specified by the measurement instructions.

2. Verify the Range code is correct for the datalogger type.

3. Verify the red power wire is correctly wired to the 12V, Switched 12V, or

SW12V module. The terminal the wire is connected to will depend on the

datalogger program.

Connect the red wire to a 12V terminal to constantly power the sensor for

troubleshooting purposes. With the red wire connected to12V, a

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

relative humidity on the yellow and blue 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).

10. 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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