Beckhoff EL3692 Documentation page 123

Commissioning
Temperature coefficient [ppm/K], tK
An electronic circuit is usually temperature dependent to a greater or lesser degree. In analog measurement
technology this means that when a measured value is determined by means of an electronic circuit, its
deviation from the "true" value is reproducibly dependent on the ambient/operating temperature.
A manufacturer can alleviate this by using components of a higher quality or by software means.
The temperature coefficient specified by Beckhoff allows the user to calculate the expected measuring error
outside the basic accuracy at 23 °C.
Due to the extensive uncertainty considerations that are incorporated in the determination of the basic
accuracy (at 23 °C), Beckhoff recommends a quadratic summation.
Example: Let the basic accuracy at 23 °C be ±0.01% typ. (full scale value), tK = 20 ppm/K typ.; the accuracy
A35 at 35 °C is wanted, hence ΔT = 12 K
-6 -2
Remarks: ppm ≙ 10 % ≙ 10
EL3692 Version: 2.1 123