Hitachi EH-A14EDR, Руководство по применению

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Chapter 3 Programming
3
– 18
3.6 Variables
3.6.1 Data memory
In HX-CODESYS programming, external I/Os and data memory (internal registers) are handled as variable names
instead of direct I/O addresses, such like “A1_switch”. If new variable name is used, below Auto Declare window
appears. Enter an each field according to following table.
Item Descriptions
Scope Choose “VAR” in normal use. If global variable is used, choose “VAR_GLOBAL”.
Refer to section 3.6.7 Global variable for further information.
Name Variable name is defined. Refer to section 3.6.3 Available characters for variable names.
Type Data type is defined. Refer to section 3.6.5 Data type.
Object In case of local variable, POU name is defined.
Initialization Initial value when program starting can be set here. If it’s blank, initialization value is 0.
Address No need to enter I/O address. HX-CODESYS will assign to free address automatically.
Comment Any text comment can be input.
Flags CONSTANT Enter a value in the Initialization field.
RETAIN The value is maintained by a battery after switch off of the PLC. If new application is
downloaded, it will be initialized. (Refer to section 3.13 Run / Stop / Reset)
PERSISTENT The value is maintained by a battery after switch off of the PLC. If new application is
downloaded, it will be maintained. (Refer to section 3.13 Run / Stop / Reset)
Bit access
Any bit data in integer type data can be accessed by adding suffix dot and number (decimal 0 to 63).
Example
WORD type (16 bits)
BOOL type (1 bit)
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