Data Sheet

HUMIDITY PROBE FOR
SENSOR SWITCHING MODULE
Page 2 of 2
Released 09/2006 Rights reserved for change in technical data! HYGROSENS INSTRUMENTS GmbH Postfach 1054 D-79839 Löffingen Tel: [phone] Fax: [phone]
Application instructions
The measuring element must be
installed at a place which is
representative of the room climate.
Air flow, radiation or other heat sources
deteriorate the measuring accuracy.
The used sensor element is suitable for humidity
values up to 90%rH and is not allowed in dew
conditions.
Pollutants in the atmosphere, organic solvents or
aggressive gases like ammonia permanently
damage the measuring element. For special
applications, the suitability of the probe should be
checked before installation.
RJ12-plug connector
The humidity sensor is connected between Pin 2
and 4. Pin 1, 3, 5 und 6 are not occupied in case
of measuring probe.
For Universal sensor-switching module, Pin 4 is
connected to AC Signal (output) and Pin 2 is the
input to measuring amplifiers (input).
View of contacts at the plug
Pin Function Description
1,3,5,6 Unoccupied
2 OUT AC output
4 IN Signal (input)
Connection for Universal sensor
switching module (156503,-17,-30)
The applicable safety regulations
should be followed! Connection and
mounting operation should be carried
out by only trained personnel after
switching off the voltage supply.
The RJ12-plug connector is meant for direct
connection to the sensor-switching module. The
plug connector is brought out through the hole in
the housing and properly secured through cable
gland. The plug connector of the probe is inserted
at the middle RJ12 socket "IMPEDANCE INPUT"
(see sketch).
Configuration of jumpers
Since the three inputs of the
module are "OR" connected, the
jumper connections "Switching
polarity" of two other unused inputs
must be kept in unwired inactive position (see
sketch). The associated LEDs below the input
socket may not glow. If this is not ensured, the
relay shall be always in ON condition!
The other two right potentiometers and jumpers of
the pin strip "ANA-MODE" will not have any
influence on the functioning of humidity probe.
The switching behaviour of the device is decided
by the jumper connections below the input socket:
In the right position, as shown in sketch, the relay
switches ON if the humidity value is below the
adjusted limiting value. In the left position, the
switching behaviour is reversed, i.e. the relay
switches ON if the humidity value is above the
adjusted limiting value. The switching behaviour of
the device can be observed at the light emitting
diode (LED). In active condition (= relay closed)
the LED glows.
Adjustment of switching point
The adjustment of switching point for impedance
input is done by a trim potentiometer "SETP IMP".
Close to the left end position (i.e. anticlockwise),
the set value is approx. 90% rH. In right end
position, the set value is approx. 35% rH.
In the simplest case, the calibration is done at a
specific switching point by means of a comparison
instrument. As soon as the desired, measured
switching point is available in the atmosphere, the
potentiometer is adjusted accordingly.
Humidity reference cells are also available as
accessories, which can provide a specific humidity
reference value. The reference cells are available
in eight different values between 11% and 85%
rH.
For checking the high switching point, the probe is
covered with palm. Due to perspiration, the
humidity increases and the electronics must
switch corresponding to "humidity" setting.
Our publications "Humidity measuring systems"
and "Humidity calibration process" are available
on request.
Adjustment of time delay
Finally, adjustment of time delay is carried out by
placing the jumper connection of the pin strip
"TIMER" at the desired position. With this, the
configuration is complete and the device is ready
for use.