Hanna Instruments HI 98170 - Manual (Page 22)

2 2
GOOD LABORATORY PRACTICE (GLP)
GLP is a set of functions that allows storage and retrieval of data regarding the
maintenance and status of the electrode.
All data regarding pH, Rel mV or ISE calibration is stored for the user to review
when necessary.
EXPIRED CALIBRATION
The instrument is provided with a real time clock (RTC), in order to monitor the
time elapsed since the last pH calibration.
The real time clock is reset every time the instrument is calibrated and the
“expired calibration” status is triggered when the instrument detects a
calibration time out. The “CAL” “DUE” tags will start blinking to warn the
user that the instrument should be recalibrated.
The calibration time out can be set (see SETUP for details, page 25) from OFF
(function disabled) to 7 days.
For example, if a 4 days time out has been selected, the instrument will issue
the alarm exactly 4 days after the last calibration.
However, if at any moment the expiration value is changed (e.g. to 5 days),
then the alarm will be immediately recalculated and appear 5 days after the
last calibration.
Notes: • When the instrument is not calibrated or calibration is cleared
(default values loaded) there is no “expired calibration”, and the
display always shows the “CAL” “DUE” tags blinking.
• When an abnormal condition in the RTC is detected, the instrument
forces the “expired calibration” status.
LAST pH CALIBRATION DATA
The last pH calibration data is stored automatically after a successful calibration.
To view the pH calibration data, press 2nd then GLP when the instrument is
in pH measurement mode.
The instrument will display the time (hh:mm) of the
last calibration.
Press the ARROW keys to view the next calibration
parameter (pressing the key):
• The date (mm.dd.yyyy) of the last calibration.
• The pH calibration offset.