M&C TechGroup EC-30_FD Operator's manual - Manual (Page 28)

28
Gas sampling and gas conditioning technology 3-4.20-ME
18.2 TEMPERATURE SETTING FOR THE COOLER
The pre-cooling stage is set at the factory to a regulated temperature of +1°C.
Current-Temp.
R
i
> 100k 
Setting-Temp.
P3
°C + -
Uref
Connect a d.c. voltmeter
to terminals 1, 2 and 3!
Uref
Utemp
R
C9
Figure 11 Temperature adjustment
Setting of the regulated temperature is done by trimming potentiometer P3, on the EC automatic
control board of the cooler. The setting range covers temperatures from 0°C to 20°C. Turning it to the
right sets a lower temperature, and turning it to the left sets a higher temperature.
Connecting an external voltmeter to plugs 2 and 3 allows the nominal set temperature to be read off
and controlled. A voltage value of 0.1V corresponds to a temperature of 1°C.
It is possible to measure and control the current temperature at measuring sockets 1 and 2.
N O T E !
Freezing up in the pre-cooling stage will endanger the operation of the
cooler unit. For this reason the cooler temperature must never fall below
+1°C!
19 TEMPERATURE SENSORS
The pre-cooling stage temperature sensor  is a PT100 element. STP 35 temperature sensors are
available for the low temperature stages  and .
19.1 CHECKING THE TEMPERATURE SENSOR OF THE PRE-COOLING STAGE
There are two methods for checking the PT100 element, as follows:
Voltage method
In order to check the sensor for the cooler currently in operation, the actual voltage at the measuring
sockets 1 and 2 of the EC automatic control board must be measured as per section 18.2 above.