GHM DeltaOHM HD2305.0, Operating Manual

Page: 13 / 30

HD2305.0
- 13 -
V1.6
5) Press DATA/ENTER to proceed with the calibration. The electrode offset mV value (OFFS) is
shown on the display for few seconds.
After a few seconds the instrument shows the measurement again, corrected according to the
new calibration,
but remains in calibration mode .
Pressed repeatedly the DATA/ENTER key allows the calibration on the point to be repeated, for
example, in order to obtain a more stable value.
6) To end the electrode calibration press pH/mV (ESC ), or continue the calibration for the second
point.
7) Extract the electrode from the buffer, clean it carefully, and insert it in the following buffer.
8) Press one time the °C/°F key (MENU) .
9) The instrument displays the value detected on the new buffer: continue by repeating the steps
from point 3.
NOTES:

After calibration, the instrument displays an electrode quality indication :
- no signal: electrode functioning.
- a small square blinking on the lower right: electrode almost exhausted.
- two small squares blinking on the lower right: electrode exhausted to be replaced.

The 3-point calibration must always be carried out according to the fixed sequence: NEU-
TRAL>>ACID>>BASIC
. The basic buffer must be the last in the sequence.

Without having pressed DATA/ENTER at all, the calibration is interrupted by pressing
pH/mV (ESC);
the previous values will continue to be used.

The buffers are always presented in the sequence set in the menu with the parameters:
-
BUFR_1,
- BUFR_2,
- BUFR_3.

The 2 point calibration is possible using the sequence BUFR_1 - BUFR_2 or BUFR_2 -
BUFR_3 or even BUFR_1 - BUFR_3.
The 3-point calibration is only possible using the exact sequence BUFR_1 - BUFR_2 -
BUFR_3
.
Allowed calibration sequences
Nu
mber
of
cali
br
a
ti
on
points
1 BUFR_1 BUFR_2 BUFR_3
2 BUFR_1 - BUFR_2 BUFR_2 - BUFR_3 BUFR_1 - BUFR_3
3 BUFR_1 - BUFR_2 - BUFR_3

In any case where no operation is performed, the “calibration” mode automatically stops
after 60 seconds.

If the calibration is rejected by the instrument because it is considered to be excessively corrupt-
ed, the
CAL ERR message will appear, followed by a long beep. The instrument remains in cal-
ibration mode and maintains the previous calibration values: at this point, if the calibration is in-
terrupted using
pH-mV / ESC , the instrument signals the anomaly through the CAL message
blinking.