Hello Group,
We currently have a system which has modules in a box(metal) with floating
digital and analog grounds.It is a Class 1 (safety) equipment.
We intend to connect the 0V of each board to protective earth (chassis) at a
common single point at the power supply.
By doing this, the conducted emissions, ESD, Surges, etc show better
results.
We have a serial port (DB9)on the device which is only used for configuring
Our concern is when a PC is connected to this port, cause in PCs the signal
ground (pin 5) is normally connected to PE.
So, when a PC is connected to the serial port of our system we may end up
with signal grounds on each end of this serial cable
connected to it's own device PE. This may cause earth loops. Since this is
only a config port, approvals may not be an issue
but functionally in the field this may create problems.
Is it common to connect digital grounds to a single point chassi ground
directly at the power supply ?
Should there be any concern from functionality point of view ? especially
when a PC is connected to our serial port.
Your comments will be greatly appreciated.
Praveen Rao
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