Mitsubishi Electric FR-A820-00046 (0.4K) Instruction Manual page 135

 Command speed and actual operation check
Check for a gap between the actual speed and commanded speed by comparing the inverter's speed command and the speed
detected by the speed detector.
System failure
134
3. PRECAUTIONS FOR USE OF THE INVERTER
3.7 Failsafe system which uses the inverter
Controller
Inverter
(speed, temperature,
air volume, etc.)
To the alarm detection sensor
Sensor