Quote:
Originally Posted by tseres
last year we had our spikes (i think 3) all with common ground and the inspectors had no problems with it.
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Can you describe this in a little more detail please? Where was the "star" point for the spike's ground? How did you connect them together?
I do not know the wiring rules off the top of my head. However, I would strongly recommend keeping the ground star points in the same topology as IFI originally intended. As an electrical/RF engineer, I spend a lot of time carefully planning my grounding scheme.
I saw one team that used CAT5 cable (normally used for ethernet) quite elegantly for their sensor wiring. It is ok to common the grounds here because they are all going to the same star point - the RC's analog sensor port.
It is also ok (unless the rules say otherwise) to common spikes together, as they are also going to the same star point.
However, I would not be comfortable commoning a ground for a spike and a sensor. The most obvious reason is that this would couple noise into the sensor. The more dangerous reason is that you probably just bypassed some of the RC's protection circuitry.
One easy way to look at it is to consider your ground path to be a tree, with your battery in the trunk. As long as it is still a tree when you are done, you are probably good.
Does it really matter here? Probably not, but it is a bad habit to get into.