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5.5.4. Support of a sensor heater
The sensors used in the P18(D) transducers are equipped
with internal heating elements to allow faster release of water molecu-
les from the sensor being flooded or working a long time in highly hu-
mid environments. Switching the heater on is possible by writing the
appropriate value to the register 4021 (see Tab. 14). Status of the heater
is available in the status register (register 4017) at the bit position 11
(if the bit 11 of the register 4017 is set to „1” - this means that the heater
is switched on).
Caution:
The transducer with a heating element switched on does not measure
the proper ambient temperature and humidity! (the temperature mea-
sured by the sensor increases and the humidity decreases). The value
200 is added to the measuring values (temperature, relative humidity)
when using the transducer with the heater switched on in order to avoid
distortions of a measurement in the measurement systems!
The P18D transducers working with a heating element swit-
ched on display a flashing symbol h.
Fig. 12. Indication of the P18D transducer operation
with a heater switched on
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