Safety Program - Mitsubishi Electric MELSEC iQ-R-R00CPU User Manual

31.2

Safety Program

Safety programs are executed at every safety cycle. Safety cycle processing is performed in the following order: safety input
(refresh), safety program, and safety output (refresh). ( Page 527 Safety Cycle Time)
Standard programs (+ END processing) are executed within the remaining time of the safety cycle time after safety programs
are executed. (Standard programs are executed until next safety cycle time starts.)
Safety input
(input refresh)
Safety program
(operation
A B
processing)
Safety output
(output refresh)
Standard program
Tsio
Tsc: Safety cycle time
Tsio: Safety program + Safety input/output processing time
(1): Store the processing times below.
• Safety CPU: SD1890, SD1891
• Safety function module: Un\G62, Un\G63
(2): Execute all safety programs. (Execute safety programs A, B, and C.)
• After executing a rising/falling instruction, this will be valid until the safety program for the next safety cycle
processing is executed. ( MELSEC iQ-R Programming Manual (CPU Module Instructions, Standard
Functions/Function Blocks))
• In safety programs, the block number of the file register (R) is not saved or restored. Data in the index
register (Z, LZ) are not saved or restored, either.
• Even if the operating status of Safety CPUs for which no safety program has been registered is STOP or
PAUSE, safety program operations other than operation processing are performed. Consequently, the
standard control processing time and device/label access service processing time will be longer.
Tsc
(1)
C (2) A B C
END
Tsio
31 RUNNING A SAFETY PROGRAM
Tsc
A B C
Tsio
525
31.2 Safety Program
31