User`s manual

9
DEVICE EXPLANATION
9 - 32
9.3 Internal System Devices
9.3.1 Special relay (SM)
9.3 Internal System Devices
Internal system devices are used for system operations.
The allocations and sizes of internal system devices are fixed, and cannot be changed by
the user.
9.3.1 Special relay (SM)
(1) Definition
Special relay stores the CPU module states (error diagnostics, system information,
etc.).
(2) Special relay classifications
Special relays are classified according to their applications, as shown in Table9.5.
(3) Special relay that can be used in the program that achieves the safety
function
In the program that achieves the safety function, only SM1000 to SM1299 can be
used.
Remark
For details on special relays which can be used by the CPU module, refer to
Appendix 1.
Table9.5 Special relay classification list
Classification Special relay
Diagnostics information SM0 to 99
System information SM200 to 399
System clock/system counter SM400 to 499
Safety CPU SM560 to 599
Boot SM600 to 699
Instruction related SM700 to 799
CC-Link Safety SM1000 to 1299