MESSTEC Power Converter GmbH
Operating Manual
TEC Controller
Document: 10100920OM
Revision: 1.1
Date: 10.10.2019
Page 24/71
5.5. Arbitrary Sensor
Almost any arbitrary temperature sensor can be used in specific applications.
Note:
The temperature sensor interface and signal processing is designed for
RTD (Resistance Temperature Detector) sensors. Do not use active or in-
tegrated circuit temperature sensors in any case!
Arbitrary sensors are specified via polynomial of 6
th
degree. The characteristic curve
is according to:
𝑅(𝜗) = 𝑅
𝜗0
∗ (1 + 𝑎
1
∗ (𝜗 − 𝜗
0
) + 𝑎
2
∗ (𝜗 − 𝜗
0
)
2
+ 𝑎
3
∗ (𝜗 − 𝜗
0
)
3
+ 𝑎
4
∗ (𝜗 − 𝜗
0
)
4
+
+𝑎
5
∗ (𝜗 − 𝜗
0
)
5
+ 𝑎
6
∗ (𝜗 − 𝜗
0
)
6
)
a
1
= coefficient 1
st
order;
unit: °C
-1
a
2
= coefficient 2
nd
order;
unit: °C
-2
a
3
= coefficient 3
rd
order;
unit: °C
-3
a
4
= coefficient 4
th
order;
unit: °C
-4
a
5
= coefficient 5
th
order;
unit: °C
-5
a
6
= coefficient 6
th
order;
unit: °C
-6
ϑ:
Temperature in °C
ϑ
0
:
Reference temperature in °C
R
ϑ0
:
Reference resistor value in Ω (R
ϑ0
= R(
ϑ) at ϑ
0
)
The configuration of arbitrary sensors allows a high degree of variety Not all values
and combinations are really reasonable.
Make sure to consider the following notes:
The result of the polynomial always must be positive in the range 0 °C to
50 °C.
The curve shape of the polynomial must be always strictly monotonic
decreasing or increasing.
The result of the polynomial should be located in a range 100 Ω to 5 kΩ.