Mitsubishi Electric MELSEC Q Series Programming Manual page 70

2 SAFETY OBSERVATION FUNCTION
(3) Operation outline
(a) When the start switch (X100) is pushed after confirming safety (safety switch
input (X200) is ON.), the STO signal (Y300) is output.
(b) Create the program so that the start switch is enabled only when the switch
is turned ON to OFF, preventing accidental start when the start switch is
shorted or welded.
(c) When the safety switch is turned OFF, the SS1 command (Y301) is turned
ON.
(d) When the safety observation error is detected in the controller or servo
amplifier during operation, the shut-off signal (Y20A/X20A) is turned OFF,
and the STO signal is immediately turned OFF.
(e) During SS1 operation, commands from the Motion CPU are ignored and
operation is at the command speed of the servo amplifier. Because the
commands from the Motion CPU are ignored, the command speed changes
when SS1 stops, and a safety observation error may occur when speed
monitoring function is being executed by the Motion CPU.
(f) When this function is used during synchronous control, axis positions of
synchronized axes can no longer be synchronized. To maintain
synchronization between axes turn the SS1 command ON after stopping the
axes.
(4) Timing chart
The timing chart for this function is shown below.
Safety input
signal such as
door signal etc.
SS1 command
SS1 status
STO status
SBC status
V
Motor speed
0
SS1/SS2
operating time
SS1 operating
Feedback speed
Command speed
2 - 33
STO status
t