ISSUE WITH POWER GROUNDING AND SIGNAL GROUNDING

Thread Starter

annapurna

Joined Feb 11, 2016
19
can we connect power ground and micro controller ground?
what will happen if we make the ground common for both?
please provide some references to understand it properly
thankyou.......
 

DickCappels

Joined Aug 21, 2008
7,997
Many microcontroller have their ground connected to power grounds. It is usually safer for the microcontroller because that way it is less likely that a connection to the microcontroller will come in contact with a voltage that can damage it. It is also important in some applications, particularly those applications in which the microcontroller must connect to other equipment that is grounded. An additional benefit is that there is less chance of electric shock or damage to people or equipment connected to the microcontroller.

Some of this is explained in the web page referenced by the link below.
http://www.analog.com/en/analog-dialogue/articles/staying-well-grounded.html
 

Thread Starter

annapurna

Joined Feb 11, 2016
19
my power line has 400V and 30A . and making the power ground and controller common, is it compulsory to isolate??? if not isolated then what wil be the consequence?
 

AlbertHall

Joined Jun 4, 2014
11,610
my power line has 400V and 30A . and making the power ground and controller common, is it compulsory to isolate??? if not isolated then what wil be the consequence?
You need to make sure that the 30A stays in the power circuit and cannot flow through the uC circuit. You have the uC circuit and the power circuit then you make just the one connection between the two grounds. The 30A stays out of the uC circuit because there is no other route back to its power source.
 

crutschow

Joined Mar 14, 2008
28,224
You do not what to connect the microprocessor power common to line common (neutral).
That's a serious shock hazard and can zap the processor.
It can be connected to earth (safety) ground of the mains.
 
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