Specifications

App - 29
Appendix 6 Special Register (SD) List for Remote I/O Station
The special registers SD are the internal registers whose specifications are specified
by the CPU and the remote I/O module. For this reason, they cannot be used by the
sequence program in the same way as the normal internal registers. However, they
can be used to write data as needed in order to control the CPU and remote I/O
modules.
Data stored in the special registers are stored as BIN values unless otherwise
specified.
Use the GX Developer, or use a READ/WRITE command sent by the sequence
program, to monitor and write to the remote I/O module's special registers.
Use the GX Developer to monitor and control the ON/OFF functions of the remote I/O
module's special relays.
Connect the GX Developer to the remote master station or the remote I/O module, and
then operate the online menu monitor and the device test. The sequence program will
read the special register according to the READ command, and write to the special
register according to the WRITE command.
The following list applies only to the special registers related to the remote I/O
modules.
The following table shows the meaning of the headings in the list.
Item Function of item
Number • Indicates the number of the special register.
Name • Indicates the name of the special register.
Content • Indicates the contents of the special register.
Explanation • Contains detailed information about the contents of the special register.
Set by
(When set)
• Indicates whether the register is set by the system or the user and when the register is
set if it is set by the system, .
<Set by>
S : Set by system
U : Set by user (with a sequence program or a test operation from a peripheral
device)
S/U : Set by both system and user
<When set>
indicated only if the setting is done by system.
Each END : Set during each END processing
Initial : Set only during initial processing (when the power supply is
turned ON, or when turned from STOP to RUN)
Status change : Set only when there is a change in status
Error occurrence : Set when an error is generated
Instruction execution : Set when an instruction is executed
Request : Set only when there is a request from the user (through SM, etc.)
Corresponding
ACPU
D9
• Indicates the special registers (D9
) corresponding to the ACPU.
(Indicates as "Change" when there has been a change in contents)
• Items indicated as "New" have been newly added for Q/QnACPU
Applicable CPU
Indicates the applicable CPU type name.
+ Rem : Can be applied to QCPU, QnACPU and MELSECNET/H remote
I/O modules.
: Can be applied to all types of CPU
QCPU : Can be applied to Q-series CPU
QnA : Can be applied to QnA series and Q2ASCPU.
Remote : Can be applied to the MELSECNET/H remote I/O modules.
Each CPU type name : Can be applied only to the specific CPU. (e.g. Q4ARCPU,
Q3ACPU)
For details on the following items, refer to these manuals:
• CPU
• QCPU User's Manual (Function Explanation, Program Fundamentals)
• QnACPU Programming Manual (Fundamentals)
• Networks
• Q corresponding MELSECNET/H Network System Reference Manual
(PLC to PLC network)
• Q Corresponding MELSECNET/H Network System Reference
Manual (Remote I/O network)
• For QnA/Q4AR MELSECNET/10 Network System Reference Manual
• SFC
QCPU (Q Mode)/QnACPU Programming Manual (SFC)