Quick Installation Guide
00825-0300-4728, Rev AA
July 2010
Rosemount 644
9
Transducer Function Block
This block contains temperature measurement data for the sensor and the terminal
temperature. It also includes information about sensor types, engineering units and
diagnostics. At a minimum, verify the parameters in Table 1.
Table 1. Transducer Block Parameters
Analog Input (AI) Function Block
The AI block processes field device measurements and makes the outputs available to other
function blocks. The output value of the AI block is in engineering units and contains a status
indicating the quality of the measurements. Use the Channel number to define the variable
that the AI block processes. At a minimum, verify the parameters of each AI block in Table 2.
Parameter
Comments
Typical Configuration
LIN_TYPE
example: “Pt 100_A_385 (IEC 751)”
SENSOR_CONNECTION
example: “2-wire”, “3-wire”, “4-wire”
PRIMARY_VALUE_UNIT
example: “Degrees C”
Sensor Matching Configuration
LIN_TYPE
“User Defined, Calvandu”
SENSOR_CONNECTION
example: “2-wire”, “3-wire”, “4-wire”
PRIMARY_VALUE_UNIT
example: “Degrees C”
SENSOR_CAL_METHOD
set to “User Trim Standard”
CAL_VAN_DUSEN_COEFF.A
enter sensor specific coefficients
CAL_VAN_DUSEN_COEFF.B
enter sensor specific coefficients
CAL_VAN_DUSEN_COEFF.C
enter sensor specific coefficients
CAL_VAN_DUSEN_COEFF.R0
enter sensor specific coefficients
Table 2. AI Block Parameters
Parameter
Comments
CHANNEL
The CHANNEL parameter defines which transducer
block measurement is used by the AI block. In the 644
Transmitter, the channel will always be set to Sensor 1.
There is no other option for this variable.
LIN_TYPE
This parameter defines the relationship between the
block input and the block output. Since the 644
Transmitter does not require linearization, this
parameter will always be set to No Linearization. This
means that the AI block will only apply scaling, filtering,
and limit checking to the input value.
PV_SCALE
Set desired measurement range and units. Units must
be one of the following:
• mV
• Ohms
• °C
• °F
• °R
• K
OUT_SCALE
For “DIRECT”, set OUT_SCALE to match PV_SCALE
HI_HI_LIM
HI_LIM
LO_LIM
LO_LO_LIM
Process alarms.
Must be within the range defined by “OUT_SCALE”
4728_Rev AA.fm Page 9 Thursday, July 29, 2010 11:41 AM
