Maintenance of theElectronic
( EPC ) PressureControllers onSRI GCs
After you plug the new sensor into the
EPC board it may need to be calibrated
since each sensor is slightly different.
Each half of theEPC board has two ad-
justable potentiometers ( trimpots ) la-
beled offset and span. The offset trim-
pot is used to adjust the display so it
reads 0.00when there is no gas pres-
sure connected to theEPC.
Remove the gas from theEPC inlet so
there can not be any pressure. If the
Actual does not read exactly 000 then
adjust theoffset trimpot on theEPC
board half ( the half you plugged the
sensor into ) se the display on the front
panel of theGC reads 000.
Reconnect the gas and find
a pressure gauge to con-
nect to theEPC output
tube. The carrier EPC
( green ) has a
convenient con-
nection point on
the left inside of
the chassis.
The hydrogen
( red ) andair
( blue ) EPCs
have good con-
nection points
on the right in-
side of the
chassis.
October 2009
Page6
Adjust so display read 000
Carrier
Hydrogenandair
