Mitsubishi Electric MELSEC Q Series Programming Manual page 56

2 SAFETY OBSERVATION FUNCTION
*Start request
P252
* SS1 delay timer
10
14
19
* STO
22
27
(2) Program example
X200
X100
0
Safety Start
switch switch
input
M0
Start switch
ON to OFF
M1
X200
Safety
Start
switch
enable
input
M3
Stop
request
T16
SS1 delay
time
M1
Y20A X20A
Start Shut-off Shut-off
enable (system) (system)FB
(3) Operation outline
(a) When the start switch (X100) is pushed after confirming safety (safety switch
input (X200) is ON.), the STO signal (Y20B) is output.
(b) Create the program so that the start switch is enabled only when the switch
is turned OFF to ON, preventing accidental start when the start switch is
shorted or welded.
(c) When the safety switch input is turned OFF, the STO signal is turned OFF
after SS1 delay time (T16) elapses.
(d) When the safety observation error is detected during operation, the shut-off
signal (Y20A/X20A) is turned OFF, and the STO signal is immediately
turned OFF.
2 - 19
PLF M0
Start switch
ON to OFF
SET M1
Start
enable
SET M3
Stop
request
K10
T16
SS1 delay
time
RST M1
Start
enable
RST M3
Stop
request
Y20B
STO signal
END