Mitsubishi Electric MELSEC iQ-R Series - Page 505

28 LABELS
28.5 Arrays
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Range of the number of array elements
The maxim number of array elements varies depending on the data type.
Precautions
■When an interrupt program is used
When a label or device is specified for the array index, the operation is performed with a combination of multiple instructions.
For this reason, if an interrupt occurs during operation of the label defined as an array, data inconsistency may occur
producing an unintended operation result.
To prevent data inconsistency, create a program using the DI/EI instructions that disables/enables interrupt programs as
shown below.
For the DI/EI instructions, refer to the following.
 MELSEC iQ-R Programming Manual (CPU Module Instructions, Standard Functions/Function Blocks)
■Array elements
When accessing the element defined in an array, access it within the range of the number of elements.
If a constant out of the range defined for the array index is specified, a compile error will occur.
If the array index is specified with data other than a constant, a compile error will not occur. The processing will be performed
by accessing another label area or latch label area.
Data type Setting range
Bit
Word [unsigned]/bit string [16 bits]
Word [signed]
1 to 2147483648
Double word [unsigned]/bit string [32 bits]
Double word [signed]
Single-precision real number
Time
1 to 1073741824
Timer
Counter
Retentive timer
Long counter
Long retentive timer
Long timer
1 to 32768
Double-precision real number 1 to 536870912
String 1 to 67108864
String [Unicode] 1 to 33554432
Structure type
Function block
1 to 32768
DI
EI
Program of the label defined as an array