Lenze DDS v2.3 - Manual (Page 17)

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Introduction
2-5
l
DDS EN 2.3
Example of access to an input variable:
(* The function block fb has an input variable in1 of type int. *)
PROGRAM prog
VAR
inst1:fb;
END_VAR
LD 17
ST inst1.in1
CAL inst1
END_PROGRAM
•
The declaration parts of function blocks and programs may contain instance declarations.
Instance declarations are not allowed in functions. A function cannot call a function block.
•
Access to the instance of a function block is restricted to the organization unit in which it was
instanced, unless it was globally declared. Function blocks should never be globally declared
as this would lead to logical errors.
•
The instance name of a function block may be used as input for a function or a function
block.
L_IOParCounterModule
byAnalogModuleNr
byFunction_CH1
bExecute
byNodeAdr
nState
byFunction_CH2
CTRL
EPM-T110
Ixxxh
Counter
PROGRAM Counter
VAR
Counter: DINT;
END_VAR
Counter is the instance name of function block L_IOParCounterModule and can be
used as input in the code.
Note!
All values remain the same from one execution of the function block to the next. Therefore function
block calls with the same arguments do not necessarily return the same output values!
Should the function block include at least one Retain variable, the whole instance is stored in the
Retain area.
2.2.4.2 Calling a function block
The input and output variables of a function block can be approached by another organization unit.
For this purpose, a function block instance must be generated and the desired variable specified
with the help of the following syntax:
.
Input writes only
Input and output reads
•
To set the input parameters on call in the IL and ST text languages, assign values to the
parameters in brackets after the function block instance name (assignment via := as for the
initialization of variables at the point of declaration).
Tip!
SFC allows function block calls in steps only.
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