Even though grounding and bonding our sensor is not primarily made for EMI (Electromagnetic interference) reduction purposes, in certain cases, it can improve the EMI behavior of the device. The idea is that the conductive chassis will form a Faraday cage, which will lead the induced current by a path of the smallest impedance to the ground (it is assumed that the intrusive device is connected with the ground directly or by chassis capacity).
To achieve the smallest impedance, you should follow these rules:
Grounding wire must be as thick and as short as possible.
Grounding wire must be as narrow as possible.
Grounding wire should not be tangled. If the sensor should be moving during operation, make a half loop only to relax cable bending stress.
Try to use star topology by connecting the grounding wire of our device directly to the grounding point. Avoid connecting multiple sensors in series.
Avoid ground loops (chassis ground connected to more than one point, for example, the cable shielding and the chassis ground) since they can form loop antenna and pick up unwanted noise more effectively. If so, the chassis ground should be disconnected at one point to break the loop.
Avoid long or tangled grounding wires. They have higher inductance (and therefore impedance) and are not able to ground high frequencies properly. They can even worsen the EMI.
