User Guide

11
USE AS REFERENCE pH METER
HI 504910 QUICK pH CALIBRATION
HI 504910 can be calibrated frequently through HI 504920 without
interrupting the normal measurement.
This is accomplished through a single point pH calibration at the pH
value of the solution monitored by HI 504910.
Perform the following steps:
1. Connect the supplied infrared optical interface cable (HI 7290) to
the calibrator and to the HI 504910 Digital Transmitter.
2. Immerse the pH electrode into the solution which HI 504910 is
measuring, as close as possible to the HI 504910 pH probe. Wait
a few seconds for the electrode to stabilize.
3. When the meter displays pH measure-
ment, press TXCAL on the HI 504920
calibrator.
4. The LCD will display "CALt" for a couple of
seconds to indicate that the calibration
of the HI 504910 transmitter is in
progress.
5. If the calibration is completed correctly,
the LCD will flash the "Good" message for
a couple of seconds.
6. The primary LCD then shows the pH
reading of the HI 504910 transmitter,
while the secondary one displays the pH
reading of the reference meter. Both pH tags blink alternatively.
Note: The two values may differ a little if the solution under
measurement is not stable. For an accurate calibration, it is
recommended to perform the above procedure only when
readings are stable.
7. To exit the calibration mode and return
to normal measurement, press TXCAL.