Mitsubishi Electric MELSEC-Q Series User Manual page 81

<Fail-safe circuit example>
YB0
*2 YB0 turns on and then off at alternatively 0.5 second intervals.
Use a contactless output module (transistor is used in the above example).
*3 If an OFF delay timer (especially miniature timer) is not available, construct the fail-safe
circuit using an ON delay timer shown on the next page.
When constructing a fail-safe circuit using ON delay timers only
YB0
*4 Use a solid state relay for the M1 relay.
Internal program
YB0
M9032
YB0
YB1
YBF
24V
0.5s 0.5s
Output module
CPU module
Internal program
YB0
M9032
YB0
0.5s 0.5s
YB1
YBF
24V
Output module
CPU module
ON delay timer
OFF delay timer *3
External load
L
L
0V
T1
*2
M1
M1
T2
M2
External load
L
L
- +
0V
T1
47
T1
1s
T2
1s
MC
- +
24VDC
T2
MC
ON delay timer
T1
1s
*4
M1
ON delay timer
T2
1s
M2
MC
24VDC
M2
MC