It is not enough to connect a differential voltage between +IN and -IN. The operational amplifier
only works properly if its reference ground (GND) isn't open, but rather connected. This is ensured
when a bridge which imc CANSAS provides with bridge excitation is connected, since -VB is at GND.
A reference ground must be established in the measurement chain. There are various techniques
as well as considerations. In some arrangements, grounding the sensor is preferred, in others,
grounding the measurement system (imc CANSAS chassis). Either way, ground loops must be
avoided.
Grounding is also recommended as a way of avoiding the buildup of high or dangerous potential
differences between exposed conducting parts (such as the chassis) and ground.
The board with the signal processor (DSP) is at internal ground potential GND. This is the module's
internal "digital ground", and is connected to the chassis as well as to the shielding of the input
plug. This internal electric potential must not "float" in relationship to the power supply or the
CAN-bus. Rather, the maximum voltage differential of 50 V to GND must not be exceeded, so GND
must be held at a suitable value. Otherwise, the module can sustain damage or malfunction. A
chassis connection is provided in the form of the shielding terminal.
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