Hach-Lange SI629 C - Manual (Page 22)

18
4. Operation
Notes:
When a calibration in 2 or 3 points is performed, start
with the standard with lowest conductivity. In this way, a
contamination is avoided.
During Calibration the instrument is in Hold state:
• Limit and cleaning relays contact are open.(Alarm OFF).
• Current output is frozen at the programmed value in
Hold.
To quit the Hold state it is necessary to return to MEASURE.
The Current output 4-20 and the Relays will activate in
10 sec.
For practical reasons, in calibration is recommended
to select the temperature manually even if you have
connected a CAT probe (Pt 1000/Pt 100).
This process involves adjusting the read values by a
conductivity measuring system (instrument and cell) ac-
cording to the values of standard solutions.
Calibration is very important for highly accurate readings.
The equipment is capable of one-, two- and three-point
calibration, and automatically recognises 147µS/cm,
1413 µS/cm and 12.88 mS/cm standards.
The calibration parameters are stored in the memory
until a new calibration is performed.
One-point calibration
This form of calibration is acceptable when measuring
conductivity values around that of the used standard.
This is the most common type of calibration. In this type,
1413 µS/cm is the most commonly-used standard.
Two-point calibration
This type of calibration is recommended for work in high
or low conductivity regions where accuracy is required.
The 147µS/cm and 1413 µS/cm standards should be
used for low conductivity regions, and 1413 µS/cm and
12.88 mS/cm for high conductivity measurements.
Three-point calibration
This type of calibration is recommended when the con-
ductivity of the samples to be measured ranges from
low to high.
4.6. Calibration
CAL. 23.2°C
1364 µS/cm
CALIBRATE
CODE 000
MEASURING 22.3°C
545 µS/cm @25°
23.2°C
Standard 147 µS/cm
CAL. 23.2°C
142.6 µS/cm
If you have a
cell without CAT,
manually enter the
temperature value.
Once the reading
is stable, the
display changes
automatically.
23.2°C
Standard 1413 µS/cm
P
1
=147,0 µS/cm
C
1
=0,393 cm
-1
Introduce the
code 100.
P
2
=1413,0 µS/cm
C
2
=0,397 cm
-1
23.2°C
Standard 12.88 mS/cm
Press to
perform 3 point
calibration.
to MEASURE
si629 C_HACH LANGE_Ed 0510.indd ANG:18 si629 C_HACH LANGE_Ed 0510.indd ANG:18 20/5/10 12:06:55 20/5/10 12:06:55