Arithmetic instructions
469
Part III FP Instructions
F282_SCAL
Linearization of 16-bit data
The function can be used for:
linearizing measured values, e.g. with non-linear sensors
rendering a heater’s flow temperature y in relation to the outside temperature x
etc.
This instruction also exists as a P instruction (for FP2/2SH, FP3/5, FP10/10SH PLC types), which
is only executed at the rising edge of the EN trigger. Select [Insert P instruction] from the
"Instructions" pane if you require a P instruction. To facilitate reuse, the instruction then appears
under "Recently used" in the pop-up menu. Press <Ctrl>+<Shift>+<v> within the programming
area to open the list of recently used elements.
PLC types
Availability of F282_SCAL (see page 1323)
Variable Data type Function
x INT Input value x
xy_data DUT The first element of an DUT-type variable that contains the
xy value pairs.
y INT Output value y
EN BOOL Activation of the function (when EN = TRUE, the function is
executed during each PLC cycle)
ENO BOOL ENO is set to TRUE as soon the function is executed.
Helpful when cascading function blocks with EN functions.
For Relay T/C Register Constant
x WX WY WR WL SV EV DT LD FL dec. or hex.
y - WY WR WL SV EV DT LD FL -
No. IEC address Set If
R9007 %MX0.900.7 permanently
R9008 %MX0.900.8 for an instant
the number of reference points is not
between 2 ... 100, or the x values are not
in ascending order (x1 < x2 < x3 < ...).
Description
The function renders the value y at position x by performing a linear interpolation based on the
neighboring reference points Pw
(xw, yw)
and Pw+1
(xw+1, yw+1)
. In this example, w is the nearest
reference point whose x value is smaller than the input value x, i.e. the function connects the
individual reference points in series and renders the output value y based on the input value x.
Data types
Operands
Error flags
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