Commissioning
EL37x2
153
Version: 3.5
The maximum deviation can also be specified directly.
Example
: Measuring range 0..10 V and measuring error < ± 0.3 % full scale value → maximum deviation ±
30 mV in the permissible operating temperature range.
Note
Lower measuring error
Since this specification also includes the temperature drift, a significantly lower measuring
error can usually be assumed in case of a constant ambient temperature of the device and
thermal stabilization after a user calibration.
This applies to analog output devices.
6.6.3
Temperature coefficient tK [ppm/K]
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
Remarks:
ppm
≙
10
-6
%
≙
10
-2
Summary of Contents for EL3702
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Page 6: ...Table of contents EL37x2 6 Version 3 5...
Page 83: ...Commissioning EL37x2 83 Version 3 5 Fig 92 Incorrect driver settings for the Ethernet port...
Page 142: ...Commissioning EL37x2 142 Version 3 5 Fig 184 Process data tab SM0 EL37x2...
Page 143: ...Commissioning EL37x2 143 Version 3 5 Fig 185 Process data tab SM1 EL37x2...
