Campbell HC2S3, Руководство по эксплуатации продукта, Страница: 22 / 42

Model HC2S3 Temperature and Relative Humidity Probe
14
9.1 Troubleshooting
Symptom: Relative Humidity is reported as
–9999
,
NAN
,
–40 °C
, or
0 %
1. Check that the sensor is wired to the correct analog input channels as
specified by the measurement instructions.
2. Verify the voltage range code for the single-ended or differential
measurement instruction is correct for the datalogger type.
3. Verify the green power wire is connected to the 12V, SW12V, or 5V
terminal. Cables longer than 3 m (10 ft) should be powered by the 12V,
rather than the 5V terminal.
4. 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
(Section 7.2.1 , VoltSE() Instruction
(p. 9)
, and Section 7.2.2 , VoltDiff()
Instruction
(p. 10)
) and temperature range.
2. Default settings are listed in Appendix D ,
Changing the HC2S3 Settings
(p.
D-1)
, which include the setting “Limit humidity output to 100%”. This
setting is “disabled” for probes purchased through Campbell Scientific.
Accuracy of the humidity measurement over temperature is shown in the
graph in Section 6 ,
Specifications
(p. 5)
. 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
greater than 100% and less than 103% to 100%. Humidity values greater
than 103% are left unchanged to indicate a problem with the probe or
measurement.
9.2 Maintenance
The HC2S3 probe requires minimal maintenance, but dust, debris, and salts on
the filter cap will degrade sensor performance. Check the white filter on the
end of the sensor for debris. If dirt or salt is engrained into the filter, it should
be cleaned with distilled water or replaced. Make sure the filter is connected
firmly with your fingers — do not over tighten.
Check the radiation shield monthly to make sure it is free from dust and debris.
To clean the shield remove the sensor from the shield. Dismount the shield.
Brush all loose dirt off. If more effort is needed, use warm, soapy water and a
soft cloth or brush to thoroughly clean the shield. Allow the shield to dry
before remounting.
Replace corroded, discolored or clogged filters. To replace the filter, unscrew
the filter from the probe and pull it straight away, being careful not to bend or
damage the sensors. Before putting on the replacement filter, check the
alignment of the sensors with the probe, and if necessary, carefully correct the
alignment before installing the filter.