IM 12A06S01-00EN-P
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4 COMMISSIONING OF pH/ORP
On the first startup, the parameters are all default values configured at the factory. For
factory defaults and setting limits see Appendix 1. If a Yokogawa sensor with ID-chip
is connected to the SA11 some of these values are automatically updated. These are
sensor characteristics and factory calibration data. Other values can be configured by the
Yokogawa HOST system, for details see the belonging User’s Manual.
4.1 Measurement setup
This section describes the features of the SA11 Smart Adapter and which parameters
can be set up by a HOST system. In principle the SA11 calculates all values, some with a
particular unit, and it is up to the HOST system which values to configure, display or use for
process control. The SA11 main measurement parameter outputs are:
• pH
• ORP1 (standard ORP value, voltage in between metal- and reference electrode)
• ORP2 (ORP-pH compensated value, voltage in between metal- and glass electrode)
• rH
• Temperature
• Impedance
If the SA11 is connected to a Yokogawa sensor with ID-chip not suitable to measure ORP
(e.g. if no LE element is present or a LE element not suitable to measure ORP), the ORP
calculated output data is disabled.
In case of a SA11-P1 type, and a sensor without LE, some features will be disabled or
restricted:
• Reference impedance check (see section 3.3.3) and reference impedance error
diagnostics: disabled
• ORP calculated output and ORP error diagnostics: disabled
• rH calculated output and rH error diagnostics: disabled
• Predictive sensor replacement (see section 3.4.5): restricted to pH ZERO and pH SLOPE
only
• LE detect (see section 3.4.1) and LE error diagnostics: disabled
4.1.1 Measurement select
In general the SA11 calculates all parameter output data. The measurement warnings (see
section 4.3) demand a pre-setting of the parameter. Per parameter one setting (to be done
by HOST system) is possible for:
• pH
pH, pH-TC, pH-matrix or pH-NEN 6411 (see section 4.1.4)
• ORP ORP1, ORP1-TC, ORP2, ORP2-TC
4.1.2 Temperature settings
The automatic temperature measurement with a SA11 Smart Adapter is based upon
a Pt1000 temperature element. It is possible to set the temperature to a fixed manual
temperature or to an external temperature which is regularly set by the HOST system.
4.1.3 Temperature compensation
The pH value generated by a pH sensor depends on the process temperature, and needs to
be compensated for this temperature. The compensation of this pH value is performed on
the Nernst equation.
Note:
ORP value does not depend on process temperature.