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5.2.4 Fully Automatic calibration
The SA11 has automatic buffer recognition for easy use and to prevent wrong sequence of
actions. This is active only when SA11 is in basic mode.
The SA11 will automatic recognize the buffer based upon a combination of a predefined
buffer set and the actual mV value measured. When the measured value is within a specified
range for pH value (fixed set on 1 pH) of one of the buffers selected, this buffer will be
automatically used as input for the stability check.
Calibration is made using standard calibration buffers. Yokogawa recommends the NIST (JIS
equivalent) standard buffers for highest accuracy, but can also select DIN 19267 or US. The
standard buffers can be found in Appendix 2. It is even possible to use a user-defined buffer.
Three types of user-defined buffer tables can be defined. These buffer tables are default
defined as sodium buffers 4.00, 7.00 and 10.00. The buffer tables have to be set by an
expert Yokogawa HOST system.
Limitations:
• Temperature during calibration must be within the limits of the selected buffer table.
• Two different buffer solutions whose difference in pH value between buffer solutions is 2
pH or more.
• Calibration method applicable only for one-point or two-point calibration.
5.3 ORP/rH calibration
The calibration modes for ORP or rH are “Manual” and “Sample” only. Calibration is
performed stepwise. Follow the prompts displayed on the screen.
A stability check is made at each measurement point. Proceed to the next step only after
the reading has stabilized.
Note:
When a sensor is replaced or exchanged, a reset of the wellness data is not
necessary. If a user wants to reset this data anyhow, this is possible by the Yokogawa
HOST system. For details see the belonging User’s Manual.