Ph + Ec Measurements - Hach senslON+ MM 374 Manual De Instrucciones

4. Operation
4.9. pH+EC measurements (Channel 1)
Measurement by stability
This is the default measuring mode for the sensION
The measurement values are momentarily displayed, while the
measurement is in process. When the electrode signal remains
invariable during a certain period of time, the reading is fixed on
the display, the reading is stable.
pH: Criterion of "standard" stability, 0.01 pH (0.5 mV) in 6 s.
EC: Criterion of stability, ± 1 digit in 6 s.
If in a certain time the reading is not stable, the instrument auto-
matically passes to continuous measurement (the measured
value is displayed all the time).
To select another stability criterion or to change measuring
parameters see "Re-programming pH+EC measurement".
Magnetic stirrer: the instrument automatically controls the
start/stop of the stirrer.
Continuous measurement
The instrument displays the value obtained by the electrode all
the time. These data can be stored or printed with program-
mable interval of time. To select this type of measurement see
"Re-programming pH+EC measurement".
From the standard measuring mode (by stability), press the key
twice to show the measured value as continuous, but without
option for data acquisition.
Measurement by time
The measurement is shown on the display after the programmed
time. To select this measuring mode see "Re-programming
pH+EC measurement".
Manual Sample ID
+
With sensION it is possible to introduce a specific
™
MM 374
ID (maximum 15 characters) per each sample using an external
PC key board or bar code. See "System", page 19.
Important note:
• Channel 1 is double; can measure pH and conductivity simulta-
neously. Can also be configured as a single channel measuring
only pH or conductivity, see "Change of units", page 17.
• Temperature compensation for the pH uses the temperature
measured by the conductivity cell. When the Channel 1 is used
as a single channel, in pH measurement the temperature should
be introduced manually or can use the temperature measured
by Channel 2, see "System configuration" page 19.
12
Manual introduction of the temperature
10-04-2007
+
.
™
MM 374
...by stability
MEASURING
pH * * *
* * *
Sample 1
MEASURING
pH * * *
* * *
Stirring
Sample 1
MEASURING
pH * * *
* * *
Stirring 25%
Sample 1
STABLE MEASUREMENT C1
pH 6.28
1215
Sample 1
Next sample
10-04-2007
...by stability
By Stability
Sample identification
MEASURING
pH * * *
* * *
Sample 1
17:15
pH+EC MEASURE
Channel 1
Press to re-program meas-
...
urement, see page 13.
Start measurement
Channel 1
MEASURING (
by stability
pH 6.23
21.4˚C
1198
uS/cm @25˚C uS/cm @25˚C
00:01 Sample 1
or or
MEASURING (
by stability
pH 6.27
21.4˚C
1200
uS/cm @25˚C uS/cm @25˚C
30% Stirring 30%
00:10 Sample 1
MEASURING (
by stability
pH 6.28
21.4˚C
1215
uS/cm @25˚C uS/cm @25˚C
Stirring 25%
00:15 Sample 1
HOLD
pH 6.28
21.4˚C
1215
uS/cm @25˚C uS/cm @25˚C
00:25 Sample 1
Next sample
Press ESC to quit measurement
17:15
pH+EC MEASURE
Channel 1
...
Start measurement
Channel 1
Manual coding: introduce
the code for the sample. A
_
PC keyboard is required.
MEASURING (
by stability
pH 6.23
21.4˚C
1198
uS/cm @25˚C uS/cm @25˚C
00:01 Sample 1
etc. etc.
Pressing twice, measure-
ment in continuous.
)
continuous
21.4˚C
00:01
To vary stirring speed
)
continuous
21.4˚C
00:10
)
continuous
21.4˚C
00:15
C1
21.4˚C
00:25
)
continuous
21.4˚C
00:01