Precautions On Programming; Errors Common To Instructions; Checking The Ranges Of Instruction Runtime Devices And Labels - Mitsubishi Electric MELSEC iQ-R Series Programming Manual

1.5

Precautions on Programming

Errors common to instructions

The following table lists the conditions under which an error occurs when the instruction is executed.
*1
Error content
An I/O number which is out of range (other than 000H to FFFH and 3E0H to 3E3H) is specified.
An I/O number which corresponds to no module is specified.
An I/O number of the module that cannot be specified by using the instruction is specified.
A network number which is out of range (1 to 239) is specified.
A network number which does not exist is specified.
• The device or label specified by the instruction exceeds the available range.
• The file register is accessed while the file register is not set in the file setting of a CPU parameter or the file register to be used in
the program is not set.
• The range of the buffer memory of the module specified by the instruction is exceeded.
• The module specified by the instruction does not have buffer memory.
*1 For a contact instruction, an error is not detected but the operation result becomes no continuity.

Checking the ranges of instruction runtime devices and labels

Checking the ranges of devices and labels
When a device or label is specified in an instruction, no range check is performed, so a program needs to be created so that
the operation result falls within the range of the relevant device or label.
If a range exceeding that of the relevant device or label is specified, no error is detected but data is written to other device or
label areas.
However, an error (error code: 2820) occurs if data is written to outside the areas.
The same applies if the label assigned to a device is specified in an instruction in the program.
Ex.
When a global device is specified and W0 is assigned after D1023 in the device/label memory
BMOV D0 D1023 K10
(1) The transfer destination is in the range corresponding to D1023 to D1032. Even though the range D1024 to D1032 does not exist, the data are written and
the data in W0 to W0007 are overwritten.
Device assignment image in
the device/label memory
D0
(1)
·
D1022
D1023
W0
·
W0007
·
W03FF
(1)
1.5 Precautions on Programming
1
Error code
2800H
2801H
2803H
2804H
2805H
2820H
2823H
1 OVERVIEW
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