Crison MultiMeter 44 Manual Del Usuario página 31

4.6.3 Calibration
5. Select and modify the following options:
Option Description
µS/mS, TDS, NaCl, Ohm
Units
Reference temperature (T.ref), 20 ºC or 25 ºC.
Temperature
Temperature coefficient (TC), 0 to 5%/ºC
compensation
Selection of the type of control and the limits values.
NO: indicates that no control with relays will be used.
Relay control
See detailed information on
Alarm.See detailed information on
Alarm
4-20 mA output,
4-20 mA output for conductivity. See detailed information on
conductivity
4-20 mA output,
4-20 mA output for Temperature. See detailed information on
º C
Selection of the current output (register) when the channel is in situation of
Hold
cleaning, programming or calibration with standards.
This process involves adjusting the values read by a conductivity measuring system
(instrument and cell) according 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
recognizes 147 µS/cm, 1413 µS/cm, 12.88 mS/cm or 80.4 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 standard used. 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 147 µS/cm and 1413 µS/cm standards should be used for low
conductivity regions, and 1413 µS/cm and 12.88 or 80.4 mS/cm for high conductivity.
If you are calibrating with more than one standard, we recommend that you start with the
one with the lowest conductivity to avoid contamination problems.
Three-point calibration
This type of calibration is recommended when the conductivity of the samples to be
measured ranges from low to high.
If you are calibrating with more than one standard, we recommend that you start with the
one with the lowest conductivity to avoid contamination problems.
See Calibration procedure, Page 25
Note: During calibration with standards, the relays assigned to the corresponding channel stay
deactivated. The 4-20 mA outputs (register) are in Hold (21 mA or last value).
* Channel 2 and 3 activated. This message appears when Individual Hold (sensors installed in
4.13, Page 49.
4.12, Page 48.
Operation
4.14, Page 51.
4.14, Page 51.

29