Datasheet

DATA SHEET
Technical changes reserved
0141 0316-144 04(2014
Dew Formation Probe for Sensor Switching Module
Application notes
As is important for all humidity probes, the measuring element should be
installed with protection against aggressive media and contaminations!
Owing to the construction of thick layer sensor, the measuring element
shows logarithmic characteristics. Hence, an adjustment is not necessa
-
ry for most of the applications.
To test the functioning of probe, a special diaphragm reference cell with
97 % RH is available. However, the measuring element can also expo
-
sed to breathing ow or cooled down on the backside up to dew point
threshold. In this condition, the electronics must register „Dew formati
-
on“.
For particular applications, the suitability of probes should be checked
before installation.
RJ12-plug connector
The DEW-sensor is connected between Pin 2 and 4 and is potential
free. The Interdigital structure is wired between Pin 4 and 3/5. Pin 1
and 6 are not occupied in case of probe. For Universal sensor swit-
ching module, Pin 4 is connected to AC Signal (output) and Pin 2 is
the input to measuring ampliers. Pin 3 and 5 are AC like connected to
ground through a capacitor.
Pin Function Description
1,6
Unoccupied
2
OUT AC output
3
CAP AC Ground
4
IN Signal (input)
5
CAP AC ground
Connections 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 „IMPE-
DANCE INPUT“ (see sketch).
Conguration 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 potentiometers and jumpers of the pin strip „ANA-MO-
DE“ will not have any inuence on the functioning.
The switching behaviour of the device is decided by the jumper con-
nections below the input socket: In the right position, as shown in
sketch, the relay switches ON if registering dew formation. In the left
position, the switching behaviour is reversed, i.e. the relay switches
ON with dry sensor. The switching behaviour of the device can be ob-
served 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“. Only a small variation is possible through
adjustment and the middle position works for most of the applications.
The adjustment range is right from approx. 93 % RH (nearly left end
position of the potentiometers, i.e. anticlockwise direction) up to ap-
prox. 98 % RH (right end position).
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 conguration is complete and the device is ready for use.
View of contacts on the plug
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