Mitsubishi Electric MELSEC Q Series Programming Manual page 68

2 SAFETY OBSERVATION FUNCTION
In the user safety sequence ladder program created in either the PLC CPU or
Motion CPU, the functional safety command starts the safety observation
function of the servo amplifier when the safety observation function changes to
an operating status.
Functional safety command bit status Operating status of safety observation
Functional safety
command
PLC CPU side
STO
SS1, SS2, SLS1 to
SLS4
Motion CPU side
OFF OFF
OFF ON
ON OFF
ON ON
OFF OFF
OFF ON
ON OFF
ON ON
2 - 31
function of servo amplifier
STO function is operating
(power supply shut-off)
STO function is stopped
(power supply in ON)
Safety observation function is stopped
Safety observation function is
operating