M&C TechGroup ECS Operator's manual - Manual (Page 28)

28
Gas sampling and gas conditioning technology 3-4.1-ME
19 CHECKING THE TEMPERATURE SENSOR
The EC/ECS cooler temperature sensor is a PT100 element as from serial numbers 95... . There are
two methods for checking the PT100 element, as follows:
1. 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.
Figure 10 shows the voltage characteristics in relation to temperature. If the measured voltage is
inside the shaded area, the sensor is defective and must be replaced.
°C
V
o
lt
a
g
e
-3
-2
-1
0
1
2
3
4
-30 -20 -10 0 10 20 30 40
Figure 11 Voltage in relation to the temperature of the cooling stage
2. Resistance method
In this case the sensor must be disconnected from pins 1 and 2 at the EC automatic control board
(Fig. 8) and removed from the cooling block. When measuring the resistance of the PT100 element,
this must be proportional to the ambient temperature. The resistance-temperature characteristics are
shown in Figure 11 below.
°C
Ohm
95
97
99
101
103
105
107
109
111
113
115
117
-10 0 10 20 30 40
Figure 12 Resistance-temperature characteristics of the PT100 temperature sensor