Micromod MOD: 1800P - MOD 30ML Identity Module (Version 2) Algorithms, Tables and Sequential Logic Functions - Manual (Page 44)

Logic Functions - Book 2
LINEARIZATION BLOCK
8-36
Piecewise and Inverse Piecewise
When piecewise or inverse piecewise linearization is used, a corresponding piecewise table
block must be configured. The piecewise block provides the means to define up to sixty X, Y
coordinates for the graph of the linearization function. In performing piecewise linearization,
the input value is "fitted" between two points in the table using the X coordinate values (Y
values if inverse piecewise is specified). The output is calculated by fitting the input between
two configured points (two pairs of X, Y coordinates) and extrapolating on a straight line to
attain the output.
To establish the link between the linearization block and the appropriate piecewise block, the
block occurrence number to the piecewise block must be indicated in the Table field of the
linearization block. For further information regarding piecewise and inverse piecewise
linearization (the search procedure and extrapolation algorithm), refer to Section 9,
Piecewise Block.
Thermocouple and Inverse Thermocouple
Thermocouple linearization is used to linearize an input signal produced by a
thermocouple of one of the supported types (B, E, J, K, N, R, S, T). The input
signal must be a floating-point value in units of microvolts, with any required
compensation to the signal already applied. The input value is converted to
temperature using conversion tables for the specified thermocouple type. The
derived output temperature value units will be as specified by the Temperature
Scale attribute.
Inverse thermocouple linearization is used to produce a microvolt value that results from a
temperature input signal for the specified thermocouple type. The temperature scale attribute
specifies what the temperature scale units of the input value.
Refer to the standard thermocouple reference tables for thermocouple temperature scales and
microvolt values. The minimum and maximums for this block are.
TYPE °C Minimum °C Maximum Microvolt Microvolt
Minimum Maximum
B 200.0 1820.0 178.18 13813.50
E –200.0 1000.0 –8824.49 76357.51
J –210.0 760.0 –8095.60 42921.90
K –200.0 1372.0 –5891.36 54874.89
N 0.0 1300 0.00 47501.82
R 0.0 1768.0 0.00 21108.17
S 0.0 1768.0 0.00 18698.15
T –257.0 400.0 –6218.97 20869.19
RTD
RTD linearization uses conversion tables to linearize an input signal produced by an RTD of
one of the supported types to a temperature in the units specified by the Temperature Scale
attribute. The input signal must be in floating point and represent, not a resistance, but a
resistance-ratio (the resistance produced by the RTD divided by the nominal RTD resistance,
which is the RTD resistance at 0°C). See RTD Material, Alpha in Section 5.4.7 of book 1 for
a description of the supported RTD types.