User Guide

• In the second case (pH value not close to the buffer) the

meter will remain in the same state until the reading be-

comes unstable or the calibration mode is quitted.

• For the second buffer value it is possible to choose be-

tween pH 4.01 and pH 10.01 (or pH 4.01 and pH 9.18 if

the NIST set has been selected). Use the  or  key to

switch between the two possibilities.

• Once selected the buffer, the procedure is the same as for

the first calibration point.

Note A time-out of 1.5 minutes is present for the pH electrode

response time. During calibration, if the pH reading is not

stable after 1.5 minutes, the device displays twice the scroll-

ing message “time-out”, then shows “WRONG” and it is not

possible to complete calibration.

• At the end of calibration, with the meter set as pH control-

ler, the instrument checks if the offset is between -30 and

30 mV and the slope between 53.5 and 62 mV/pH. If the

values are not within these ranges, the message “OLd

ProbE” scrolls twice across the LCD. The electrode is still

working, but it is necessary to perform a cleaning proce-

dure (see “Electrode conditioning and maintenance” and

“In-line Cleaning” sections) or replace it.

If the offset is outside the -60 to 60 mV range, the “dEAd

ProbE” message will scroll across the LCD and the corre-

sponding error is activated. The electrode has to be replaced

as soon as possible because there is no reliability on the

measured pH values.

One-point calibration

A one-point calibration at a value different from the standard

buffer values is possible by entering the desired calibration

value. This is the actual pH value at the current calibration

temperature.

• Enter the pH calibration mode (no matter if the standard or

NIST buffer set is selected), then press the

SETUP key while the secondary LCD is dis-

playing the first buffer value (pH 7.01 or pH

6.86).