Mitsubishi Electric MELSEC Q Series Programming Manual page 60

2 SAFETY OBSERVATION FUNCTION
(3) Operation outline
(a) When the safety switch input (X200) is turned OFF, the speed monitor
request signal (SOS request signal) is turned ON after SS2 delay time (T17)
elapse.
(b) When SOS starts or the safety observation error is detected during SOS, the
shut-off signal (Y20A/X20A) is turned OFF. Create the separate sequence
program where the shut-off (such as STO) is executed by the shut-off signal
as interlock.
(c) SOS is released by reset switch input (X101). Create the program so that
the reset switch is enabled only when the switch is turned OFF to ON, which
prevents accidental start when the reset switch input (X101) is shorted or
welded.
POINTS
The operation of SOS request signal is not required in user sequence program of
PLC CPU side. However, create the separate sequence program of both Motion
CPU side and PLC CPU side when the output signal (Y) is controlled (such as door
lock release) by status of SOS.
Use the speed monitoring executing bits (Refer to Section 4.3.3.) of corresponding
block No. of shared device as interlock.
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