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Programming Manual ecomatController/60-1 (CR711S) Operating System V2.5.0.n
2017-12-19
Programming
Create PLC application
>
8.2.2
Supported variable types
Retain variables ................................................................................................................................... 79
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► Familiarise yourself with the following CODESYS functions!
Local variables
→ Online help > CODESYS Development System > Reference Programming >
Variable Types and special Variables > Local Variables - VAR
Global variable list
→ Online help > CODESYS Development System > Reference Programming >
Variable Types and special Variables > Global Variables - VAR_GLOBAL
Network variables
(currently not supported)
→ Online help > CODESYS Development System > Exchanging Data on the
Network > Network Variables
The device supports the following variable types:
Variable type
Declaration
Scope of validity
Memory behaviour
local
In the declaration part of the POU
Applies only to the POU in which it has
been declared
volatile
local retain
non volatile
global
in the global variable list (GVL)
applies to all POUs of the project
volatile
global retain
non volatile
network
In network variable lists
Values are available to all projects in
the whole network if the variable is
contained in their network variables
lists.
Volatile
Network retain
non volatile
For performance reasons, do not overuse 64 bit variables!
CAN network variables are not supported!
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Retain variables
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Variables declared as
RETAIN
generate remanent data. Retain variables keep the values saved in
them when the device is switched on/off or when an online reset is made.
Typical applications for retain variables are for example:
• operating hours which are counted up and retained while the machine is in operation,
• position values of incremental encoders,
• preset values entered in the screen device,
• machine parameters,
i.e. all variables whose values must not get lost when the device is switched off.
