The sensor offset is intended as the offset from 7.0; values <= +/- 0.6 can be considered reasonable,
whereas, higher values indicate that the sensors (pH and/or reference) require some maintenance. The
drift is automatically controlled by the probe during the calibration. If the drift is lower than the preset
limit during the following 20 seconds, the calibration is achieved; otherwise, the message:
pH sensor error, see Operator’s Manual
will appear after which the system returns to the "Calibration Menu". If no error is detected, the probe
asks the operator to select the pH temperature compensation mode.
Automatic temperature compensation ?
Should a special and fixed temperature compensation be requested, the reference temperature value
must be entered:
pH reference temperature:
At the end of this procedure, the programme shows the sensor list.
Note
pH variations in function of temperature of the pH7 (Phosphate) and pH4 (Phthalate) buffer solutions:
Temperature (°C) pH4 pH7
0 4.00 7.12
10 4.00 7.06
20 4.00 7.02
25 4.00 7.00
30 4.01 6.99
40 4.03 6.97
50 4.05 6.96
60 4.08 6.97
70 4.12 6.98
80 4.16 7.00
90 4.21 7.03
5.5.6 Redox sensor calibration
Once selected the sensor to be calibrated, the following message appears:
eH sensor calibration
Select the available number of Redox Buffers
Buffer solutions:
This message allows the operator to enter the number of "REDOX buffer" solutions from a minimum of
2 to a maximum of 10. Selecting 0 enables a special calibration function, which imposes a factory default
calibration value and immediately terminates the calibration procedure (the default coefficients are used
to convert the sensor readings in mV).
Selecting a value of buffer solution greater than 1 starts the REDOX sensor calibration sequence.
Immerse Redox and Reference sensors into
the calibration cup filled with the 1st REDOX BUFFER
Type <any key>To continue, <ESC>To leave
Pull out the calibration buffer cup from the accessory kit and fill it with the redox LOW concentration
buffer solution. The buffer cup has been designed to simultaneously fit over the eH and the reference
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