LAQUAtwin series (EC) Operation
2
CODE: GZ0000472457
Basic Operation
Calibration
Calibration is required before measurement.
Use standard solution within the measurement
range in the specifications.
Tip
Calibration values are saved even if the meter
is switched OFF.
Calibration value is rewritten if calibration is
repeated using the same standard solution.
Measurement
Note
If a measured value is out of the specified
measurement range, "Or" is displayed for
upper range and "Ur" is displayed for under
range.
Ambient air may cause the measured values
to fluctuate. To reduce environmental interfer-
ence, close the protection cover.
When you have a problem with the calibration
or measurement, refer to frequently asked
questions.
Measurement display change
Measurement display change is available on
LAQUAtwin-EC-22 and LAQUAtwin-EC-33.
The display mode switches as follows by press-
ing the MEAS switch in the AS mode.
LAQUAtwin-EC-22:
Between conductivity and temperature alter-
nately
LAQUAtwin-pH-33:
Among conductivity, TDS, and temperature
Power ON
1. Press and hold the ON/
OFF switch.
The power is switched ON,
and the meter model num-
ber is displayed on the LCD.
Power OFF
1. Press and hold the ON/OFF switch.
The power is switched OFF.
Precaution on sample setting
Place an appropriate amount of a sample or stan-
dard solution into the measurement cell without
trapping bubbles inside. If not, the measurement
may be inaccurate.
Calibration points
The number of calibration points is dependent on
the meter model.
LAQUAtwin-EC-11:
Up to two-point calibration at 1413
μ
S/cm and
12.88 mS/cm
LAQUAtwin-EC-22 and LAQUAtwin-EC-33:
Up to three-point calibration at 1413
μ
S/cm,
12.88 mS/cm, and 111.8 mS/cm
Appropriate
Too little
Cell Electrode
Cross-section of the measurement cell
Multi-point calibration
1. Open the protection cover and place some
drops of the standard solution into the
measurement cell.
Rinsing the sensor with the standard solution
beforehand will provide a more accurate cali-
bration as it will reduce sample crossover con-
tamination.
2. Close the protection cover and press the
CAL switch.
and
blink, and the calibration value is
displayed.
After the calibration is complete,
and
stop blinking and the measured value is dis-
played.
The calibration value at 25
C is displayed for 1
s and the display returns to the measurement
mode automatically.
3. Open the protection cover and remove the
standard solution. Then remove moisture
on the sensor by gently dabbing with a soft
tissue.
This completes the 1st point calibration.
4. To perform 2nd point calibration, repeat
steps 1. to 3.
Calibration error
If
blinks and Er4 (error dis-
play) appears, the calibration
has failed.
Perform electrode conditioning.
Check that the correct standard solution is used,
and repeat calibration after cleaning the sensor.
If the calibration repeatedly fails when using the
correct standard solution(s), the sensor may
have deteriorated. Replace the sensor with new
one.
Protection cover
Sample setting
1. Open the protection cover and put some
drops of sample into the measurement cell.
2. Close the protection cover.
Measurement mode
The auto stable (AS) mode and the auto hold
(AH) mode can be selected. Refer to "
Mea-
surement mode change" (page 4) for the opera-
tion to set the measurement mode.
Auto stable (AS) mode
This is the default setting.
appears when
the measured value meets the stability criteria.
If the value changes,
disappears.
1. Confirm that the meter is in the measure-
ment mode, and place a sample on the sen-
sor.
When the read value meets
the stability criteria,
appears and the reading is
locked.
2. Document the displayed value when
appears.
If the read value does not meet the stability cri-
teria,
disappears and the reading changes
with time.
Auto hold (AH) mode
appears when the measured value meets
the stability criteria. The reading then locks
and will not change until the MEAS switch is
pressed for the next measurement.
1. Confirm that the meter is in the measure-
ment mode, and place a sample on the sen-
sor.
2. Press the MEAS switch.
The auto hold function is acti-
vated.
blinks until the mea-
sured value has stabilized.
When the measured value is stable,
stops
blinking and the displayed value is locked with
and
displayed simultaneously.
3. Document the displayed value.
4. Press the MEAS switch.
The auto hold function is deactivated and
disappears.
Be sure to perform this step before starting the
next measurement. Or, you may mistake the
displayed hold value for the next measured
value.
