Answer / guest

A Cold Loop check is cold because it is done without
powering the loop.

A cold check consists of checking wire continuity from the
field instrument through junction boxes and through DCS/PLC
marshalling panel terminals to the control panel. Once
continuity has been confirmed, then a Hot Loop Check is
performed on the Loop's I/O.

A Hot loop check is 'hot' because it is done with the loop
powered up.

A Hot loop check consists of
- simulating a process input at the field instrument and
then checking the instrument's output and the response to
the process signal input at DCS/PLC.

- simulating outputs at the control end and checking for
correct response at the field end.

Carl Ellis
Measure First

Answer / vikaspanwar47

Hot loop check is power up checking .cold loop checking is continuity only. 

Answer / krishnan kumar sharma

Hot loop cheak on point stabilise the instrument in field and the cold loop cheak from the junction box to DCS /PLC .

What are continuances of connecting earthing and shield of branch cables (instrument to Junction box), at the same earthing pot provided on JB? Is it ok, or may produce some problem? 

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