Sensor Adjustment
The function differential measurement is also suitable for the correction of
measured values of a sensor. Many sensors must be adjusted more frequently
to compensate for instabilities.
In most cases, a temporary
zero point correction
will be sufficient.
Firstly, the measured value must be brought to zero, i.e.:
Temperature sensors must be put into ice water
Pressure and force transducers must be released
Hoses of dynamic pressure probes must be removed or
Pitot tube must be removed from the flow channel
pH probe must be placed in pH 7 buffer solution
Conductivity probe must be taken out of the substance and dried
Afterwards, the display of the measured value can be set to zero by operating
the key
CLEAR
. This procedure corresponds to a zero point adjustment, as
described in the manual section 6.3.10. For probes with a scaling the base
value will be maintained, i.e. a pH probe will not indicate pH 0.00 but pH 7.00
after the adjustment.
Unlike other ALMEMO
®
instruments, the correction values will not
be stored in an EEPROM of the sensor but will be lost when
switching over in function MEASUREMENT or when switching the
instrument off.
With the following sensors a
slope correction
can be performed in addition,
when a corresponding calibration value is provided at the sensor:
pH probe
FY A8PH-xx:
pH 4.0 or pH 10.0
Conductivity
FY A641-LF:
2.77 mS/cm
or
FY A641-LF2:
147 µS/cm
O
2
saturation FY A640-O2:
101 %
7.5 Continuous Measuring Point Scan
To also obtain the max and min values of those measuring points that are not
indicated and to ensure a continuous temperature compensation of probes for
pH and dynamic pressure, it is possible to set a continuous measuring point
scan for sensors with several channels (see man. 6.5.1.3).
The continuous measuring point scan can be activated by pressing the key
MEASUREMENT
during switching on the instrument. For control purposes an
arrow will be indicated in the display on the right above the dimension. When
switching off, the instrument will return to the standard setting.
Press key
when switching on the instrument:
MESSEN
HOLD
MIN
MAX
CORR
M
DIM
ALMEMO
2190-2
19
Measurement
