Output values
Scaling
The relationship between the output values and scaling paramaters for the Cerabar S
is as follows:
FIELD_VAL = 100 x
(CHANNEL VALUE - XD_SCALE_MIN)
(XD_SCALE_MAX - XD_SCALE_MIN)
The L_TYPE parameter influences the signal conversion.
Direct:
PV = CHANNEL_VALUE
Indirect:
PV =
FIELD_VAL x (OUT_SCALE_MAX - OUT_SCALE_MIN) + OUT_SCALE_MIN
100
Indirect square root:
PV =
FIELD_VAL x (OUT_SCALE_MAX - OUT_SCALE_MIN) + OUT_SCALE_MIN
100
The XD_SCALE and OUT_SCALE values are expressed in engineering units at 0% for
MIN and 100% for MAX.
Output response
Parameter Description
PV
Either the primary transducer block value used to execute the block or a
process value associated with it. Comprises value and status.
OUT
The primary value output as a result of executing the analog input block.
Comprises value and status.
FIELD_VALUE
Raw value of field device in % of PV range with a status reflecting the
transducer condition before signal characterisation L_Type or filtering
PV_TIME. Comprises value and status.
Parameter Description
CHANNEL
Selects the measured value to be input to the analogue input block
0 = no channel defined
1 = primary value, here it is pressure or linearization value
2 = secondary value, here it is: sensor temperature
XD_SCALE
Scales the transducer block value in the required engineering units (EU).
OUT_SCALE
Scales the output value in the required engineering units (EU).
L_TYPE
Sets the linearization type:
DIRECT: the transducer block value bypasses the scaling functions
INDIRECT:the transducer block value is fed through the linear scaling
functions
INDIRECT SQRT: the transducer block value is fed through the square
root scaling functions
Parameter Description
LOW_CUT
Not relevant to level measurement!
Determines a threshold for square root linearisation below which the
output value is set to zero.
PV_FTIME
Sets the time constant for the output value.
Cerabar S FF 3 Foundation Fieldbus Interface
Endress+Hauser 25
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