Instruction manual

Instruction manual αlpha DO 2000
15
displayed value to the correct value. Press the ENT key to accept the value and the status of
the probe is displayed.
Note: If the displayed value is not within ±50% of the high point value, the controller will
not accept the high-level calibration and retains the previous calibration values.
Note: If there is a calibration error, the controller displays “CAL ERR” and exits to the
measurement mode (for direct access calibration mode) or to the setup menu (for
calibration mode accessed via Setup mode).
10. After calibration, the controller automatically displays the condition of the probe in the upper
display and the temperature in the lower display. You can view these values without calibration
--- see Section 5.4 for instruction. The probe condition is re-determined after each calibration.
11. Press the ENT key (or CAL key) to return to the measurement mode (for direct access
calibration mode) or to the setup menu (for calibration mode accessed via Setup mode).
Note: When calibrating with manual temperature compensation, the controller
automatically changes from the preset process temperature to the calibration
temperature. After leaving the Calibration mode, the controller switches back to process
temperature (for setting the calibration temperature and the process temperature, see
Section 6.3)
5.3 Dissolved oxygen Calibration in % saturation of oxygen
A one-point calibration is done in air. When you carry out a two-point calibration, you need a
standard D.O. buffer solution that matches the low value, which is 0%.
This transmitter features a one-point or two-point calibration for dissolved oxygen.
SETUP
SETUP
SETUP
SETUP
HOLD HOLD
HOLD
HOLD
CAL
HOLD
READY
READY
ENT
ENT
ENT
ENT
1-PT
2-PT
CAL
CAL
100.0
1.00
2.00
24.5
CAL
CAL
MEAS
CAL
ERR
24.5
100.0
HOLD
ENT
ENT
0.0
%
HOLD
SETUP
SETUP
CAL
%
90.0
o
C
o
C
%
CAL
A
TC
ENT
ENT
ENT
Displayed value should be
< 10% of high point
Displayed value should be
within +/- 50 % of high point
Calibration error occurs if calibration value
is > 10% or > +/- 50% of high point
during 1 or 2 point calibration
DO
CAL
ERR
1. Enter Calibration mode as described in section 5.1. The display shows “CAL DO”.
2. Press the ENT key to start calibration. The display shows “1-PT CAL” by default. Use ▲ or ▼
keys to select one point “1-PT CAL” or two point “2-PT CAL” dissolved oxygen calibration.
3. Press the ENT key to confirm the one point or two points selection.
4. For One-Point Calibration, only calibration at the 100% level is possible. The probe is allowed
to equilibrate with air. The “CAL” indicator flashes at the top. When reading is stable, the
“READY” annunciator comes on. Press the ENT key to accept the high level calibration (100%)
and the controller displays the status of the probe
.
Note: If the displayed value is not within ±50% of the high point value, the controller will
not accept the high-level calibration and retains the previous calibration values.