Suntex CT-6110-POL, Operation Manual

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8.4 pH Calibration
The instrument provides two-point standard buffer solution calibration. By using 2
value standard buffers to calibrate the electrode’s slope and zero point (Asy, Offset or
Zero point). According to different combination of standard buffers, the TECH, NIST,
Any buffer solution, totally three calibration modes are provided. When calibration of
pH electrode, it is necessary to turn off the motor in the motor setup. Move the sensor
assembly box to the clean position of supporting plate, and let the pH electrode dip
into standard buffer. Please be noted that if motor is still in operation while calibration,
the instrument will stop the motor automatically. After calibration is finished, please
remove the sensor assembly box back to top of flow-through chamber
8.4.1 TECH mode
The electrode is automatically calibrated according to pH value and temperature
of TECH standard buffers (pH4.01, pH7.00, pH10.00). The range of zero point and
slope of the electrode is also determined. If one of them is over the range, the
display shows error message of zero point and slope failure. (See appendix Table 1,
pH/temperature table of TECH standard buffers)
8.4.2 NIST mode
The electrode is automatically calibrated according to pH value and temperature
of NIST standard buffers.( pH1.68, pH4.01, pH6.86, pH9.18, pH 12.45). The range
of zero point and slope of the electrode is also determined. If one of them is over
the range, the display shows error message of zero point and slope failure. (See
appendix Table 2, pH/temperature table of NIST standard buffers)
8.4.3 Any mode
The electrode measures mV value of known standard buffers. According to
theoretic slope and the temperature of standard solutions, the display shows an
approximate pH value. Then, you can calibrate the electrode by freely adjust the pH
value as those of the standard solutions’. There is not a zero point range failure
determination by the instrument but only the slope range determination. If the slope
is over the range, the display shows error message of slope failure.
8.4.4 Definition of calibration parameter
You can calibrate the electrode by any sequence. As different calibration point
method is applied, the definition of the zero point and slope different.
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