Mitsubishi Electric MELSEC Q Series Programming Manual page 71

• For the QnUDVCPU and QnUDPVCPU:
The device range is checked during index modification.
It is also possible not to allow checking the device range using the parameters.
The timings for checking the device change during index modification are shown below.
Instruction
Contact Instructions
Association instruction
Comparison operation instruction (LD)
Comparison operation instruction (AND)
Comparison operation instruction (OR)
Instructions other than the above
*4 When the data after index modification exceed the user specified device range, the operation results in OFF without causing an error.
*5 When the data after index modification exceed the user specified device range, it may cause an error. (Error code: 4101).
*6 For the executions conditions for each instruction, refer to the descriptions page for each instruction.
*7 The PLS instruction and PLF instruction are excluded. (The PLS instruction and PLF instruction always check the device range during
index modification.)
■Switching between 16-bit and 32-bit range of the index setting
When switching between 16-bit and 32-bit range, check the positions of the index setting in the program.
Since the specified index register (Zn) and next index register (Zn+1) are used for index setting in 32-bit range, make sure not
to overlap index registers being used.
Timings for checking
*4
Always
It follows the execution conditions for the instruction.
4 PROGRAM CONFIGURATION
*5*6*7
4
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4.6 Index Setting