Beckhoff EL47 Series, Документация

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Commissioning
EL47xx 110 Version: 2.7
Fig. 134: Adding a Scope project into an already existing project
Step 2a: Creation of a PLC variable within a POU
Within the TwinCAT 3 development environment an input variable as an array with respective amount than is
given by the oversampling factor have to be defined at first how it’s illustrated in an example for the POU
“MAIN” and an oversampling factor 10 with structured text (ST) as follows:
PROGRAM MAIN
VAR
aU1_Samples AT%I* : ARRAY[0..9] OF INT;
END_VAR
The identification “AT%I*” stands for swapping out this array variable to link it with the process data objects
(PDOs) of a terminal/box later. Notice that at least the number of elements has to be the same as the
oversampling factor so that the indices can be set from 0 to 9 also. As soon as the compiling procedure was
started and ended successful (in doing so no program code may be present) the array appears into the
solution explorer of the TwinCAT 3 development environment within the section PLC under “..Instance”.
The following illustration shows extracts of the solution explorer on the right. As an example that linking of an
array variable to a set of oversampling process data is represented herewith: