13
AUTO ENDPOINT MODE
The Auto Endpoint feature allows the user to freeze the display when
a stable reading is reached.
To enter the Auto Endpoint mode, press the ALT and AutoEnd keys.
The MEM symbol will blink on the LCD until measurements become
stable, then readings (pH/mV and temperature) are frozen on the
display.
By pressing the RANGE key it is possible to switch between pH and
mV measurements.
While in Auto Endpoint mode, frozen readings can be logged by
pressing the LOG key (See "Logging function" section).
To exit from Auto Endpoint mode, press again the CAL and AutoEnd
keys. The meter will return to continuous measurement mode.
Note
: By entering the setup mode, by log consulting or by pressing
the ALT and GLP keys, the meter will automatically exit from
the Auto Endpoint mode.
pH CALIBRATION PROCEDURE
For greatest accuracy, it is recommended to calibrate the instrument
frequently. For a faster procedure, it is possible to calibrate in 1 point,
but it is always a good practice to calibrate in 2 points.
A two-point calibration can use any combination from the following
sets of pH buffers:
1.68
4.01
(6.86 or 7.01)
(9.18 or 10.01)
12.45
or
3.00
(6.86 or 7.01)
(9.18 or 10.01)
12.45
E.g. in the case of a two-point calibration in the acidic range (from 0
to 7 pH), use the pH 7.01 (or 6.86) buffer as first solution and pH
4.01 as second one; if testing in the alkaline range (from 7 to 14
pH), use the pH 10.01 (or 9.18) buffer as second solution.
Due to electrode conditioning time, the electrode must be kept
immersed a few seconds to stabilize. The meter is equipped with a
stability indicator and the user will be guided step by step with easy
indications on the LCD during the calibration. This will make the
calibration a simple and error-free procedure.
20
GOOD LABORATORY PRACTICE (GLP)
Note:
Press the ALT and DEL keys to escape without data deletion.
When viewing through the logged data, the "NUL" message will be
displayed when selecting a deleted sample.
To delete all data in memory:
• Press the ALT and DEL keys while in
normal operating mode. The "del All"
message will appear on the LCD and the
"CFM" indication will start blinking ask-
ing for confirmation.
• Press the ALT and CFM keys to confirm deletion.
Note:
Press the ALT and DEL keys to escape without data deletion.
Note:
If no samples are stored in memory and a deletion is
attempted, the meter will show the message "Zero" and then
returns to normal operating mode.
GLP is a set of functions that allows the storage or retrieval (when
necessary) of data regarding the maintenance and status of the
electrode.
PROBE LIFE VERIFICATION
At the end of calibration, the meter checks if offset is between -30 and
+30 mV and the slope between 53.5 and 62 mV/pH. If the values
are not within these boundaries, the message "old probe" scrolls across
the LCD. The electrode is still working, but it will be necessary to perform
a cleaning procedure (see electrode cleaning and maintenance sec-
tion) or replace it.
If the offset is outside the -60 and +60 mV range or the slope is
outside the 40 to 70 mV/pH interval, the "dead probe" message will
scroll across the LCD; the readings will blink on the upper LCD to warn
the user that they are not reliable.
CALIBRATION ALARM TIME-OUT
The calibration alarm time-out is available only for pH calibration.
It is possible to set (through setup code "dUE") the number of days
before the next required calibration procedure. User can set a value
