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DEWE-ORION-1616-10x
2.4 Analog signals
The block diagram below (figure 1) gives an idea of the analog input configuration. The
DEWE-ORION-1616-10x consists of 16 separate input amplifiers and analog to digital converters. Each input
has four different gains for getting the input voltage range from ±1.25 V to ±10 V.
CH 7+
ADC 7
HW Offest and
Gain correction
AISENSE1
S 0
AGND
CH x+
ADC x
CH 1+
ADC 1
CH 0+
ADC 0
CH 15+
ADC 15
HW Offest and
Gain correction
AISENSE2
S 1
AGND
CH x+
ADC x
CH 9+
ADC 9
CH 8+
ADC 8
Figure 1: Analog input configuration
The configuration can be changed between single ended (referenced to AGND) and sensed (referenced to
sense) mode. The sensed mode is similar to a differential input. The difference to real differential input is that
there is just one minus input available in sensed measurement mode. With this technique the influence of
ground loops between signal source and the DEWE-ORION-1616-10x can be completely eliminated.
Figure 2 shows the principle of the sensed mode configuration. Usually the level of the signal source is
referenced directly to the minus point, which is usually its power supply ground. On the other hand without
sensed configuration the DEWE-ORION-1616-10x is also referenced to its power supply ground. Due to the
supply current and the line resistance of the signal source and the AD board the ground of both is different.
The result of this chain would be an offset error.
Signal
source
DEWE-ORION-1616
Power
suppy
CH x
AGND
Sense
I
SOURCE
I
ORION
AGND
Figure 2: Sensed mode configuration
In the sensed configuration the reference voltage is taken directly at the minus (or power ground) of the sen
-
sor to remove this offset error.
Note: In sensed configuration the input range off all channels have to set to the same value!
Содержание DEWE-ORION-1616-10 Series
Страница 56: ...C2 Notes...
