RHEONIK Messgeräte GmbH
REV. I, Apr. 2004
.
Operation Manual RHE 07, 08, 11
Page
32
Note for HT Sensors:
-
High temperature sensors RHM HT need special grounding.
Check ground wiring according to diagram.
-
Insulation resistance to earth ground for high temperature sensors should be > 1MOhm *.
* The relatively low resistance is caused by the hygroscopic characteristics of the used ceramic con-
struction materials and varies with the moisture inside the sensor.
A resistance of i.e. only a few hundred KOhm shows a sensor that is completely moist. That leads to
failures or non-function (please contact the person responsible at your local representative, to solve
this problem).
5.2. TEMPERATURE CALIBRATION
Temperature measurement is already factory calibrated. Normally a new temperature setup or new
recalibration is not necessary. The PT100 is connected by 3 wires, so that the measurement is just
influenced by one wire resistance.
For extreme long cable length there is a software
Adjust
Funktion for compensating the wire resis-
tance.
This can be done in the
Adjust Menu
. For this the actual temperature must be well known, or a
resistor simulating a certain temperature has to be connected instead of the meter PT100.
Enter the correct temperature by entering a positive or negative offset value and press the adjust
push-button. After this procedure the temperature reading will be ok.
