Specifications

sigmadue - IEC 61131-3 Function Block Library
44
1-3-34 RTD LINEAR RESCALING (FOR MICROPAC ONLY)
FB Prototype MP_RTD_LIN
Input parameters
Output parameters
Description This function block returns a linearization of the input value as function of a gain
and an offset value calculated as the following equation:
RTD_OUT = AI * AI_M + AI_Q
The FB then performs a first order filter on the converted value. Please note that
the filter constant TAU has to be greater than the cycle time used for the task
where the FB is used.
Default values
Label Type Description Range
AI REAL Analogue input value. [mA] 4.0... 20.0
AI_M REAL
Gain coefficient: a specific value for each channel is
specified on the documentation [num]
0.0... 90.0
AI_Q REAL
Offset coefficient in micro Ampere: a specific value for
each channel is specified on the documentation [µA]
-0.999999...
0.999999
SEL_C_F BOOL Degree conversion selectioN °C/°F
TAU RE AL
Filter time constant: a value of 0.0 is intended to
disable the filter action and the output will assume
the input value [s]
Reasonable
range
0.0... 60.0
Label Type Description Range
RTD_OUT REAL Converted RTD value
AI
AI_M
AI_Q
SEL_C_F
TAU
REAL
REAL
REAL
BOOL
REAL
¡
¡
¡
¡
¡
REAL RTD_OU
T
¡
Label Default Value
AI 4.0
AI_M 1.0
AI_Q 0.0
C_F_SEL
FALSE = °C degrees
TAU 0 .1
Filter response
Time
Output
Input
1
0
0
.0
9
8
.0
9
5
.0
8
6
.5
6
3
.2
0.0
%
TAU 1 2 3 4