Mitsubishi MELSEC QCPU User Manual

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MELSEC-Q/QnA
3 CONFIGURATION OF INSTRUCTIONS
3.6 Cautions on Programming (Operation Errors)
Operation errors are returned in the following cases when executing basic instructions and
application instructions with CPU module:
• An error listed on the explanatory page for the individual instruction occurred.
• No intelligent function module or special function module is installed at the designated I/O No.
position when using the buffer register.
• The relevant network does not exist when using a link device.
• No network module is installed at the designated I/O No. when using a link device.
POINT
(1) When a file register setting has been made but no memory card has been
installed, or when no file register setting has been made, no error will be
returned even if an attempt is made to write to the file register.
However, "FFFF
H
" will be stored if an attempt is made to read from the file
register at which this write operation was attempted.
(1) Device range check
Device range checks for the devices used by basic instructions and application instructions in
CPU module are as indicated below:
(a) No device range check is made for instructions dealing with fixed-length devices (MOV,
DMOV, etc.).
In cases where the corresponding device range is exceeded, data is written to other
devices.
For example, in a case where the data register has been allocated 12 k points, there will be
no error even if it exceeds D12287.
DMOV K100 D12287
D12287 and D12288 have been
indicated here, but because
D12288 does not exist, the
contents of some other device
will be destroyed.
Device range checks are not conducted also in cases where index modification is being
performed.
(b) Device range checks are conducted for instructions dealing with variable-length devices
(BMOV, FMOV, and others which designate transfer numbers).
In cases where the corresponding device range has been exceeded, an operation error will
be returned.
For example, in a case where the data register has been allocated 12 k points, there will be
an error if it exceeds D12287.
K100 D12287 K2
D12287 and D12288 have been
indicated here, but because
D12288 does not exist, an
operation error is returned.
BMOV
REMARK
1) : See section 3.4 (3) for the internal user device allocation order.
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Mitsubishi MELSEC QCPU Specifications

General

Brand	Mitsubishi
Model	MELSEC QCPU
Category	Controller
Language	English