[mikets]

Our cRIO is mounted in a wooden box, so it wouldn't contact our robot chassis. Not that we have any deliberate connection of the cRIO chassis to the battery's negative terminal, I can understand 2 and 3, but why is it a problem that the cRIO chasis is grounded to the battery's negative terminal? Wouldn't the black lead of the 24V supply is exactly the negative terminal of the battery? In fact, I measured the voltage between the negative terminal of the battery and the black lead of the 24V supply which is the ground of the cRIO. The voltage between them is in the mV so it is practically shorted to the battery's negative terminal. In any case, we do not connect the cRIO chassis to the negative terminal of the battery (at least not deliberately). I will check 2 and 3 tomorrow.