Hardware Manual COMBILOG 1020
34
4.3 Internal Reference Voltage, Offset- and Drift
Correction
An internal reference voltage serves to adjust the entire analog
signal processing automatically.
Especially for measurement of extreme low voltages, currents
and resistances, the configuration software features an additional
compensation of temperature drift. With current- and voltage
measurement, this is realized by an internal offset measurement.
The measured offset is subsequently applied to correct the meas-
ured values. For Maximum accuracy with current measurement
(temperature drift less than 25 ppm/K) it is recommended to ac-
complish the measurement via an external shunt with a corre-
spondingly low temperature coefficient (< 5 ppm/K). For this pur-
pose, the input channel has to be configured as a voltage input.
For resistance measurement, a drift correction requires an addi-
tional input channel which has to be equipped with a suitable ref-
erence resistance. This resistance should have a low tempera-
ture coefficient (< 5 ppm/K). In the configuration table, this chan-
nel has to be defined as a reference channel with resistance input
for drift correction, whereby the nominal value of this resistance
(at 20°C) has to be indicated.
Using the above described methods, the analog inputs can al-
most completely be kept free from temperature drift.
Summary of Contents for COMBILOG 1020
Page 1: ...COMBILOG 1020 Datalogger Hardware Manual Version 3 09...
Page 2: ...Hardware Manual COMBILOG 1020 2 Issue 03 11 2005 Technical data are subject to change...
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Page 12: ...Hardware Manual COMBILOG 1020 12...
Page 86: ...Hardware Manual COMBILOG 1020 86 Bild 8 1 Example Master Slave System...
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