16 |
P a g e
The Calibration mode is entered by writing a 1 to the Calibration Mode bit. While in the calibration mode the
calibration registers may be accessed, the Capture may be used to capture real time value and the Calibration Start
may be set.
When the Calibration Start bit is set the Calibration Status bit will remain set until the calibration process is complete.
Setting the Calibration Reset bit will clear the calculated Offset values.
5.2
RTD Descriptor
The RTD Input interface provides interfaces to type 100, 500 and 1000 ohm 385 Curve, 100 ohm 392 Curve and 100 ohm
3916 Curve RTD devices in 2, 3 and 4 wire configurations. A single RTD connection is supported. The Sensor Configuration
and Sensor Device fields may be written to provide control of the overall function of the channel and the RTD type used.
Offset
Name
Value
Description
0x00
Measurement Type
0x21
RTD (Temperature)
0x01
Data Type/Format
0x66
Float, writeable
0x02
Configuration
0x4?
Determines RTD type
0x03
Sensor Device
0x??
Determines connection type
0x04..0x08
UOMR
“°C”
Units of measure
5.2.1
RTD Measurement Types
The RTD interface provides a measurement of Temperature in °C.
Sensor Type
SI Derived
Units
Measurement
0x21
°C
RTD Temperature
5.2.2
RTD Input Data Type/Format
The SP-005 supports extended configuration and provides factory calibration. All data values are returned as 32-bit
floating point values.
RTD Input Data Type
7
6
5
4
3
2
1
0
Smart
Sensor
Sensor
Writeable
Factory
Calibrate
Reserved
Data Type
0
0
?
0
0x06 == FLOAT
5.2.2.1
Data Type
The 4-bit Data Type field determines the type of data of the specific sensor.
5.2.2.2
Factory Calibrate
The Factory Calibrate bit is used during factory calibration. It is a read only bit that applies to specific sensor types. If
set, factory calibration is performed on the raw sensor reading PRIOR to user scaling.
5.2.2.3
Configurable Enable
The Configurable bit indicates that the Sensor Configuration and Sensor Device fields may be overwritten by user
configuration information. If clear, only the Sensor Configuration LOCK bit may be set, allowing the user to overwrite
the Unit of Measure string.
5.2.2.4
Sensor Writeable
If the Sensor Writeable bit is set the sensor value may be overwritten with a preset value. This capability is useful in
sensors such as up/down counters, where a preset, or possibly a zero value must be written to the sensor value.
