Metrohm 726 Titroprocessor - Manual (Page 184)

8.9 CAL
726 Titroprocessor, Instructions for use 178 178
8.9 CAL
Automated calibration of pH electrodes is possible as well as manual cali-
bration. Individual buffer sets can be defined and stored in a method. The
calibration can be carried out as a simple run in dialog operation with man-
ual change of the buffer solutions. If a sample changer is used the calibra-
tion procedure can be carried out fully automatically. The necessary sample
changer commands can be programmed in detail in a calibration loop.
The CAL* mode creates the following system variables:
R$$ End result
X$$ Intermediate result (not shown in report)
C$$ Common variables (automatic assignment)
AP Asymmetry pH value, pH(as)
SL Slope of the calibrated electrode
IM Initial measured value at start of calibration (in mV)
CM Closing measured value at end of calibration (in mV)
IT Initial temperature at start of calibration in °C
CT Closing temperature at end of calibration in °C
MD Mode duration (total measurement period) in s
No live displays are possible in the calibration mode. However, it is possible
to carry out calculations using existing system variables, see page 118ff.
The calibration data produced are entered on the Devices & Manual Control'
page. The corresponding calibration curve is also available.
8.9.1 Simple calibration
Calibration parameters
CAL* Clibration
Sensor Signal drift 2 mV/min
Meas. input A1 Equilibr.time auto s
Temperature 25.0
°C
Comment
Comments on calibration mode
(50 characters)
The commentary on the mode is used for identifying the
specific measurement within a determination. This is
chiefly used for more complex methods with several ti-
tration or measuring modes.
Signal drift
Limit for measurement drift
0.5…2…999 mV/Min | off
The measured value is only accepted when the variation
in the sensor measurement falls below the given value
for the measurement drift. If this is delayed then the
measurement will nevertheless be accepted when the
preset delay period (see below) has elapsed.