14 15
The pH calibration can not be performed if the pH electrode
is broken or leaking or the reference electrode is broken or
dirty and an error is active. The ORP calibration can not be
performed if the “Reference electrode broken or dirty” error is
active. The temperature probe should be connected to the
instrument.
Initial Preparation
Pour small quantities of pH 7.01 (HI 7007) and pH 4.01
(HI 7004) or pH 10.01 (HI 7010) solutions into individual
beakers. If possible, use plastic beakers to minimize any EMC
interference.
For accurate calibration use different beakers for each buffer
solution, the first one for rinsing the electrode and the second
one for calibration. By doing this, contamination between
buffers is minimized.
• Enter the calibration mode, select
the pH calibration (by moving
through the menu with the æ and
keys), then press the CFM key.
• Choose the pH buffer set between the two available ones:
the standard set (4.01, 7.01, 10.01) and the NIST set (4.01,
6.86, 9.18). For the standard set confirm the “Std”; for the
NIST set confirm the “niSt” (use the æ and keys for select
between the two options).
The default buffer set is the one used for last calibration,
even if the procedure was not completed.
• Once confirmed the set of buffer val-
ues, the primary LCD shows the
measured pH value, while the second-
ary LCD displays the first required buffer
value.
Two-point calibration
• Remove the protective cap from the pH electrode and im-
merse it into the buffer solution (e.g. pH 7.01) together
with the Potential Matching Pin and the temperature probe,
then stir gently.
HI 504920 pH reading. Both pH tags blink alternatively.
• To return to normal mode, press ALT and TXCAL.
• If a communication error between
the portable meter and the transmit-
ter occurs, the primary LCD shows
the “rSEr” message: check the in-
terface cable and connections.
• If the LCD shows “...”, verify that the HI 504910 transmit-
ter be configured for pH (not for ORP) measurement.
Note Whenever a pH or ORP calibration is performed by means of
HI 504920, the HI 504920 date and time are automati-
cally set in HI 504910.
USING HI 504920 AS TERMINAL FOR HI 504910
Select code 90 in Setup mode and press CFM to confirm.
The HI 504920 enters the Terminal mode and the LOG tag
blinks on the LCD.
Note In this situation it is not necessary to connect the electrode to
the HI 504920 portable meter, which is working as key-
board and LCD for the HI 504910 transmitter.
To enter the calibration mode press
(ALT+) CAL.
Enter the correct password and press the CFM key. If a wrong
password is entered, the instrument returns to the previous
mode.
Note If the meter is set to measure ORP (setup item G.00), the pH
calibration, pH reading offset adjustment, and pH offset and
slope are not available. If the meter is configured for pH, no
ORP calibration can be selected.
Note Any calibration procedure can be aborted at any time by
pressing (ALT+) CAL, and the instrument returns to the previ-
ous mode.
pH CALIBRATION
To perform any pH calibration procedure, the instrument has
to be set as pH meter.
The meter can be calibrated through a one-point or two-
point calibration.
