Display
Action
Remark
If the zero offset of
the electrode is too
large (> ± 200 mV),
the CAL ERR error
message is generated.
In that case the elec-
trode cannot be cali-
brated.
Zero adjustment
Allows use of electrodes with differing nominal zero (DURAFET II pH electrodes)
Press
CAL
key,
enter code 1001
Select with
key,
edit number with
key,
proceed with
ENTER
Immerse electrode in a pH 7.00
buffer.
Enter the temperature-corrected
pH value in the range 6.50 to 7.50
using the arrow keys
(see buffer table).
Confirm with
ENTER
.
APT4000PH is in the
Hold mode.
If an invalid code is
entered, the
APT4000PH returns to
measuring mode.
66
APT4000PH
Ready for calibration
The“CAL”, and “enter” icons are
flashing
Display (3 s)
Stability check:
The measured mV value is dis-
played.
The “hourglass” icon is flashing.
Note:
Stability check can be
stopped (by pressing
CAL
). However, this
reduces calibration
accuracy.
67
Display
Action
Remark
At the end of the adjustment pro-
cedure asymmetry potential [mV]
(based on 25 °C) of the electrode
are displayed. Proceed with
ENTER
These is not the final
electrode value!
Zero and slope must
be determined with a
complete 2-point cali-
bration (cal 1100)
(see following pages).
Security prompt.
Display of pH value (alternately
with Hold) and temperature,
“enter” flashes, Sensoface is
active.
Place electrode in process.
Press
ENTER
to end the
zero point calibration.
After end of calibra-
tion, the outputs
remain in Hold mode
for approx. 20 sec.
Information on zero adjustment
After having adjusted the nominal zero point, be sure to calibrate the electrode
following one of the procedures as described on the next pages:
• Automatic calibration with Calimatic
• Manual calibration
• Data entry of premeasured electrodes