Lenze DDS v2.3 - Manual (Page 135)

Drive PLC Developer Studio
Editors
7-13
l
DDS EN 2.3
Application example
An operating hour meter that is to continue counting after a mains failure.
•
All other variables will be re-initialized either with the standard initial values (0 or FALSE) or
with the defined initial values.
Example:
VAR RETAIN
rem1:INT; (* 1. retentive variable *)
END_VAR
7.2.7 Constants, typed literals
Between the keywords VAR CONSTANT and END_VAR, all constants are declared.
•
Constants can be declared locally or globally.
Syntax:
VAR CONSTANT
<Identifier>:<Type> := <Initialization>;
END_VAR
Example:
VAR CONSTANT
con1:INT:=12; (* 1. constant *)
END_VAR
For a list of permitted constants refer chapter on Operands. ( ^ 13-1)
7.2.8 Retentive constants
Between the keywords VAR CONSTANT RETAIN and END_VAR, all retentive constants are
declared.
•
Retentive constants can be declared locally or globally.
Syntax:
VAR CONSTANT RETAIN
<Identifier>:<Type> := <Initialization>;
END_VAR
Example:
VAR CONSTANT RETAIN
Acceleration: DINT:=10000; (* acceleration time *)
END_VAR
7.2.9 Keywords
•
All editors require keywords to be written in capitals.
•
Keywords must not be used as variable names.
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