User Guide

13
SLOPE ADJUSTMENT
OFFSET ADJUSTMENT
• If the reading lies outside
this range, adjust the slope
adjustment trimmer on the
transmitter for a reading just
within this range.
The unit is now calibrated.
A complete calibration of the transmitter
module is advised periodically.
This calibration procedure requires the
HI 8427 or the HI 931001 pH and ORP simu-
lator to simulate the ORP electrode.
HI 8427 or HI 931001 produce a known sig-
nal into the system so that the faults of the
system can be isolated.
• Connect the ORP transmitter to the simu-
lator.
• Set the simulator to 0 mV and adjust the
offset trimmer to read 12 mA on the
ammeter or 0 mV on the HI 8615L dis-
play (HI 8615L only).
INPUT
-VE LO
O
P
+VE LO
O
P
mV
HI931001
pH/mV
Calibrator
SLOPE ADJUSTMENT
OFFSET ADJUSTMENT
mA