Thermo Scientific AquaSensors™ DataStick™ Modbus ...

5.1.2.2 Scale Factors
Most Scale Factors are fixed, e.g., the Cell Constant Scale Factor is fixed at 1000, but some depend on
the type of Sensor Head installed in the DataStick. The Sensor Value Scale Factor is one of these. For
example, when the installed Sensor Head is pH, the Sensor Value Scale Factor is 100, but when the
installed Sensor Head is ORP, the Sensor Value Scale Factor is 1.
5.1.3 Class Configuration Value
This class of variable represents a value that configures some aspect of the operation of the DataStick,
e.g., Sensor Units, or the Modbus Adapter. Variables of this class are static, non-volatile, and are stored
in the DataStick or the Modbus Adapter.
This class of variable exists in two types: integer and float.
5.1.4 Class Information
This class of variable is used for informational purposes only. Variables of this class are static, nonvolatile,
and are stored in the DataStick, e.g., Main Serial Number.
This class of variable exists in two types: integer and ASCII. All of them have been grouped into a
single register bank.
5.1.5 Class Calibration
This class of variable instructs the DataStick to perform the action of calibrating itself. All calibrations
involve a multi-step procedure, and one of the steps involves writing a calibration variable.
5.1.6 Class Status
All variables of class Status have been grouped into a single register bank.
5.1.6.1 Originating in the DataStick
This class of variable is used for indicating the status of the DataStick, e.g., Calibration Status.
However, variables of this class are not static.
Variables of this class are of type integer.
5.1.6.2 Originating in the Modbus Adapter
There is a unique Status variable that originates in the Modbus Adapter itself called Communications
Status. The values that this variable can take on are defined in Table 8. On power-up, when
communication has started but before the Modbus Adapter has read the Sensor and Temperature Values
from the DataStick, Communications Status is Okay; while the DataStick is absent, Communications
Status is “Communications error”; and, while the Modbus Adapter is communicating with the
DataStick, Communications Status is “Data is valid”.
This variable is of type integer.
Thermo Scientific AquaSensors DataStick Modbus Communications User Guide 12