Mitsubishi Electric Melsec-QS Series Safety Application Manual page 76

APPENDIX
(a)+(b)
WDT
(SM)
Master
station
monitoring
timer start
Master
station
Ladder
CC-Link
Safety
Remote
station
(Input
side)
Input
signal
CC-Link
Safety
Remote
station
(Output
side)
(a) to (e) in the figure corresponds to (a) to (e) in Table App. 1.
App
Appendix.1 Calculation Method of Safety Response Time
- 3
POINT
POINT
(1) If setting value of the safety data monitoring time is equal to or less than the
value gained by the calculation formula above, an error may occur even in
normal communication status.
If setting value of the safety data monitoring time is needlessly long, the time
taken for (c) in TableApp.1 may lengthen in the case of a safety
programmable controller error, resulting in excessive delay of safety response
performance.
(2) To show the maximum value of safety response time, this manual uses WDT,
the maximum value of SM (Scan time), instead of SM to the calculating
formula.
For the usual calculation, substitute for WDT, SM is used.
(3) When the safety CPU module detects CC-LINK DATA RECEPTION
TIMEOUT (error code: 8320 to 8322), increase the safety refresh monitoring
time and safety data monitoring time as needed.
(WDT n) m
LS
Master station
monitoring
time-out decision
Safety refresh
monitoring time
Ladder Ladder Ladder Ladder
Safety data monitoring time
TableApp.1.
FigureApp.1 Timing chart
(C)
Master station
monitoring
time-out decision
Safety refresh
monitoring time
Ladder Ladder
(d)+(e)
(WDT n) m
Safety Safety
power supply CPU
module module
Ladder Ladder
CC-Link Safety
CC-Link Safety
remote I/O station
Safety input
signal
Emergency stop switch
Output
signal
CC-Link CC-Link
Safety master Safety master
module module
CC-Link Safety
remote I/O station
Safety output
signal
Safety relay