User Guide

Note If (ALT+) SETUP are pressed instead of CFM, the calibration

value selection is aborted and the meter reverts back to a

two-point calibration.

Note If the calibration is performed by means of the HI 504910

internal keyboard and LCD (not through the HI 504920

meter), the calibration date and time are set to a default 1/1/

2002 00:00 : in this case disable the calibration time-

out in HI 504.

ORP CALIBRATION

Check that the code 90 has been entered in Setup mode.

To perform ORP calibration it is necessary to connect an HI

931001 or HI 8427 simulator to the BNC socket.

The meter has to be set as ORP controller.

• A two-point calibration has to be performed: the first point

value is 0 mV and the second one can be chosen between

350 mV and 1900 mV.

• Enter the calibration mode, select the ORP calibration (use

the  and  keys to move through setup menu) and press

the CFM key.

• Set the HI 931001 or HI 8427 simulator to 0 mV.

• The primary LCD will display the cur-

rent mV measure and the secondary

LCD will show the first calibration

point (0 mV).

• When the reading becomes stable, if the ORP value is

close to the calibration point, the “CFM” indicator starts

blinking; otherwise the “WRONG” indicator blinks and

the “CAL” is fixed on.

• In the first case press CFM to confirm calibration. The

meter will proceed showing the scrolling message “Press

CFM again to confirm the current buffer or right to es-

cape” (to prevent from confirming the calibration point

inadvertently). Pressing again CFM the secondary LCD will

display the second calibration point.

• In the second case (blinking “WRONG”) the meter will

remain in the WRONG state until the reading becomes

unstable or the calibration mode is exited by pressing the

CAL key.