User Guide

41
ANALOG INPUT CALIBRATION
The analog input is already factory calibrated. However, the
user may also perform a 2-point calibration at 4 and 20 mA.
It is sufficient to perform the calibration on one range only.
• Connect a mA simulator (e.g. HI931002) to the analog
input of the controller (#12 at page 7)
• Press and hold first CFM and then
CAL to enter the analog input cali-
bration mode.
• Execute the password procedure.
• Select code 0 via the arrow keys for analog input calibra-
tion and confirm with CFM. CAL will blink on the LCD.
• The secondary LCD will display “4”
for the first calibration point. The pri-
mary LCD will display the conductivity
reading.
• Set the mA simulator to 4 mA and wait for the reading to
stabilize, CAL will stop blinking and an intermittent CFM
will prompt the user to confirm the calibration.
• If the reading stabilizes at a reading significantly variant
from the first calibration point, an intermittent ERROR will
prompt the user to check the input.
• If everything is satisfactory the sec-
ondary LCD will display “20” for the
second calibration point.
• Set the mA simulator to 20 mA and wait for the reading to
stabilize, CAL will stop blinking and an intermittent CFM
will prompt the user to confirm the calibration.
• Press CFM to confirm. The meter will
return to normal operational mode.
Calibration procedure may be interrupted by pressing CAL
again at any time. If the calibration procedure is stopped this
way, or if the controller is switched off before the last step, no
calibration data is stored in non-volatile memory (EEPROM).