Timing Of Speed Monitoring Function - Mitsubishi Electric MELSEC Q Series Programming Manual

2 SAFETY OBSERVATION FUNCTION

2.4.2 Timing of speed monitoring function

The speed monitoring function is started by the speed monitoring request signal.
Turn on the speed monitoring request signal after the motor is decelerated to the
safety motor speed or lower by the speed change instruction (CHGV) etc. in user
program. If the speed monitoring request signal is turned ON when the motor speed
exceeds the safety speed, "safety observation error (error code: 110)" occurs after
speed monitoring error detection time, and the shut-off signal turns OFF.
When the speed monitoring request signal is accepted within the safety speed, the
following checks are executed.
• Safety observation error is not occurred.
• Parameter check (Refer to Section 2.4.4, 2.4.5) is completed correctly.
• Speed error detection check (Refer to Section 2.4.12) is completed correctly.
After the check is completed successfully, Motion CPU and PLC CPU start the speed
monitoring, and the speed monitoring enable signal is turned ON. If any error occurs,
the shut-off signal is turned OFF and the speed monitoring does not start.
If the speed monitoring request signal is turned ON when the safety observation error
occurs, "Safety observation warning (error code: 210)" occurs and the speed
monitoring does not start.
The speed monitoring is ended by turning OFF the speed monitoring request signal.
Turn OFF the speed monitoring request signal after ensuring the safety in user
program. When the speed monitoring is completed, the speed monitoring enabling
signal is turned OFF, and the normal operation becomes available.
In addition, the speed monitoring enable signal is not turned OFF even if the safety
observation error is detected during speed monitoring.
Speed monitoring
start switch etc.
Speed monitoring
request signal
Speed monitoring
parameter check/
Error check
Speed monitoring
enable signal
V
Motor speed
Safety
motor speed
0
Checking
within 200ms
Decelerates to below the safety
motor speed before the speed
monitoring request signal is on.
Unsafe state
2 - 11
Speed monitoring
t
Unsafe state