Appendix 2 Special Register List - Mitsubishi Electric MELSEC-Q Series User Manual

APPENDICES

APPENDIX 2 Special Register List

Number
Name
Meaning
Explanation
Set by (When set)
For details on the following items, see these manuals:
• Networks
App - 5
The special registers, SD, are internal registers with fixed applications in the
programmable controller.
For this reason, it is not possible to use these registers in sequence programs in the
same way that normal registers are used.
However, data can be written as needed in order to control the CPU module.
Data stored in the special registers are stored as BIN values if no special designation
has been made to it.
The headings in the table that follows have the following meanings.
Item
• Indicates special register number
• Indicates name of special register
• Indicates contents of special register
• Discusses contents of special register in more detail
• Indicates whether the relay is set by the system or user, and, if it is set by the system, when
setting is performed.
<Set by>
S : Set by system
U : Set by user (sequence program or test operation from GX Developer or the like)
S/U : Set by both system and user
<When set>
Each END
Initial
Status change
Error
Instruction execution : Set when instruction is executed
Request
• For Q MELSECNET/H Network System Reference Manual (PLC to PLC
network)
Function of Item
Indicated only for registers set by system
: Set during each END processing
: Set only during initial processing (when power supply is turned
ON, or when going from STOP to RUN)
: Set only when there is a change in status
: Set when error occurs
: Set only when there is a user request (through SM, etc.)
MELSEC-Q
App - 5