4 - 42 4 - 42
MELSEC-Q
4 SEQUENCE PROGRAM CONFIGURATION AND EXECUTION
CONDITIONS
4.7.2 Direct mode
(1) Definition of direct mode
In the direct mode the communication with the I/O modules is performed when
executing sequence program instructions.
With High Performance model QCPU, direct mode I/O processing can be
performed by using direct access inputs (DX) and direct access outputs (DY).
For details on direct I/O, see Section 10.2.1 and 10.2.2, respectively.
Input
module
Output
module
CPU (operation processing area)
2
1)
2)
3)
4)
5)
High Performance model QCPU
Output (Y)
device
memory
GX Developer
input area
Input (X)
device
memory
DY25
Y20
DX0
3
1
Remote input
refresh area
• When an input contact instruction has been executed:
OR operation is executed for the input module's input information 1) and peripheral
device input area's input information 2), and the result is stored in the input (X)
device memory. Then this data is then used as input information 3) at sequence
program execution.
• When an output contact instruction has been executed:
Output information 4) is read from the output (Y) device memory, and a sequence
program is executed.
• When an output OUT instruction has been executed:
The sequence program's operation result 5) is output to the output module, and is
stored in the output (Y) device memory.
Fig.4.9 I/O Information Flow in Direct Mode
REMARK
1: The GX Developer input area can be turned ON and OFF by the following:
• Test operation by GX Developer
• Writing from a serial communication module
2: The output (Y) device memory can be turned ON and OFF by the following:
• Test operation by the GX Developer
• A network refresh by MELSECNET/H network system
• Writing from a serial communication module
• CC-Link automatic refresh
3: The remote input refresh area indicates the area used when automatic refresh
setting is made to the input (X) with MELSECNET/H and CC-Link.
Automatic refresh of the remote input refresh area is performed during END
processing.
