Label And Device - Mitsubishi Electric MELSEC iQ-F Series Programming Manual

Label and device

Specification method
Labels and devices can be directly described in the ST program. Labels and devices can be used for the left or right side of an
expression or as an argument or return value of a standard function/function block.
For available labels, refer to the following.
Page 32 LABELS
For available devices, refer to the following.
MELSEC iQ-F FX5 User's Manual (Application)
■Device expression with type specification
A word device can be used in ST language as an arbitrary data type by adding a device type specifier to its name.
Device type specifier
N/A
:U
:D
:UD
:E
The following shows the devices to which device type specifiers can be added.
• Data register (D)
• Link register (W)
• Module access device (U\G)
• File register (R)
■Device specification method
The following methods can be used for specifying a device.
• Indexing
• Bit specification
• Nibble specification
• Indirect specification
For details, refer to the following.
MELSEC iQ-F FX5 User's Manual (Application)
MELSEC iQ-F FX5 Programming Manual (Instructions, Standard Functions/Function Blocks)
6 ST LANGUAGE
60
6.1 Configuration
Data type
Generic data type ANY16.
When only devices are used in arithmetic operations,
the data type is Word [signed].
However, when the data is specified as a device
without the type specification in the argument part of
FUN/FB, the data type is the one of the argument
definition.
Word [Unsigned]/Bit String [16-bit]
Double Word [Signed]
Double Word [Unsigned]/Bit String [32-bit]
FLOAT (Single Precision)
Example Description
D0 When no type specifier is added to D0
D0:U The value when D0 is Word [unsigned]/Bit string [16-bit]
D0:D The value when D0 and D1 are Double word [signed]
D0:UD The value when D0 and D1 are Double word [unsigned]/Bit
string [32-bit]
D0:E The value when D0 and D1 are single-precision real
numbers