Appendices - Mitsubishi Electric MELSEC-Q Series User Manual

APPENDICES

APPENDICES
APP
APPENDIX 1 Special Relay List
Number
Name
Meaning
Explanation
Set by (When set)
For details on the following items, see these manuals:
• Networks
App - 1
Special relays, SM, are internal relays whose applications are fixed in the
programmable controller.
For this reason, they cannot be used by sequence programs in the same way as the
normal internal relays.
However, they can be turned ON or OFF as needed in order to control the CPU and
remote I/O modules.
The headings in the table that follows have the following meanings.
Item
• Indicates the number of the special relay.
• Indicates the name of the special relay.
• Indicates the nature of the special relay.
• Contains detailed information about the nature of the special relay.
• 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 (in sequence program or test operation at a peripheral device)
S/U : Set by both system and user
<When set>
Each END
Initial
Status change
Error
Instruction execution : Set when instruction is executed
Request
• Far Q MELSECNET/H Network System Reference Manual (PLC to PLC
network)
Function of Item
indicated only if setting is done 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 is generated
: Set only when there is a user request
(through SM, etc.)
MELSEC-Q
App - 1