User Guide

12
CALIBRATION MODE
The calibration mode allows to calibrate the pH/ORP and
temperature inputs.
The instrument is factory calibrated for all these parameters.
Periodical calibration of the instrument is recommended, in
particular when greatest accuracy is required and at least bi-
yearly.
The electrode can be calibrated over only one point but,
when possible, it is always good practice to perform a 2-
point calibration.
QUICK SINGLE-POINT pH CALIBRATION (through HI 504920)
A quick single point pH calibration at the pH value of the
solution monitored by HI 504910 transmitter can be per-
formed. HI 504920 serves as a reference pH meter.
Unlike the usual calibration with buffers, this quick proce-
dure is carried out without having to interrupt normal
measurement.
Note For better accuracy, from time to time it is recommended to
perform a 2-point calibration procedure, which allows to ad-
just not only the offset but also the slope of the pH probe.
• Connect the HI 504920 meter to HI 504910 through
the infrared interface cable.
• Immerse the pH electrode of the HI 504920 meter into the
solution measured by HI 504910, as close as possible to
the pH probe of HI 504910. Wait a few seconds for stabi-
lization.
• When the HI 504920 meter displays
the pH measurement, press TXCAL (HI
504920 must be out of the HI 504910
terminal mode).
• The LCD will display “CALt” for a couple
of seconds to indicate that the calibra-
tion of the HI 504910 transmitter is in
progress.
• If the calibration is completed correctly,
the LCD will flash the “Good” message
for a few seconds. (Also the red LED
flashes once).