Campbell Scientific CS215 Temperature and Relative Humidity Probe - Manual (Page 23)

CS215 Temperature and Relative Humidity Probe
9.2 Maintenance
The CS215 probe requires minimal maintenance.
• Check the radiation shield monthly to make sure it is free from dust and
debris.
• Clear the white filter on the end of the sensor of 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.
9.3 Calibration
The life of the humidity chip element is quoted as many years with a typical
drift of less than 1% per year when used in ‘clean’ environments. Because it
can be difficult to know what the sensor has been exposed to and because the
element is relatively inexpensive, we recommend replacing the sensor element
at the normal interval you would recalibrate similar probes, e.g. annually.
Replacing the element effectively brings the probe back to a factory calibration
state both for temperature and relative humidity.
If you wish to have an old element’s calibration checked in order to formally
record the probe’s pre-calibration state (pre-sensor replacement), you can
measure its performance by plugging it into another sensor.
9.4 Sensor Element Replacement
To replace the element:
1. Disconnect the sensor from the 12 V power supply.
2. Remove the filter by unscrewing it in a counter-clockwise direction when
looking towards the tip of the sensor.
The filter cap unscrews from the probe. Attempting to pull it
off will destroy it.
3. Wash your hands to avoid getting dirt or grease on the element.
It is virtually impossible to touch and damage the sensing elements
which are enclosed within the black molded plastic at the tip.
However, if dirt, salt, or grease are left on the plastic during the
process of handling the element, it may influence the
measurements made.
4. Identify the sensor element. FIGURE 9-1 shows a side-view of the end of
the probe and sensor element. Before removing the element, carefully
study the probe, note its orientation, and read the following description:
• The element plugs into the black plastic socket that protrudes by about
1 mm from the end of the metal body of the sensor.
CAUTION
NOTE
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