Answer Posted / guest

Probably HART communicator used for online & onfield
calibration.As per my experience,I always used to do
calibration by step given bellow:
1.First,put transmitter loop in CAL mode.In CAL mode
controller the hold last PV for reference.causes without
stop or disturb process we can do calibration earlier
(depends on process)
2.Connect HART to the transmitter +ve & -ve
terminal.observed parameter on HART
display.e.g.pressure,dp,current output singnal.& note down.
3.Then close the isolation valve of both HP & LP tapping &
loose the both HP & LP side vent plug.In this condition
transmitter shoud show zero dp because same atmospheric
pressure actig both side.If transmitter showing zero dp
transmitter is normal & If it is not showing zero,then
there is some error in dp.
4.If transimtter showing error in dp then on HART go to
diagnosis-calibration-sensor calibration-dp trim.enter the
zero dp at atmospheric condition and come back on basic
setup display,transmitter will showing 4 mA current
output.means calibration is ok.then u can take transmitter
on line.and don't forget to checked leakage from impulse
tubing & vent plug.

Another procedure is Bench calibration.Using pressure &
calibrator we can check transmitter.even without HART we
can do bench calibration.

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