Speed Error Detection Feature
Speed Error Detection
The Speed Error Detection function is used to protect the motor from over speeding/rollback.
If the speed of the motor is detected to be outside of the defined range for a set time then the drive will trip.
Speed Error Detection Parameters
Parameter Number | Parameter Name | Units | Default | Available Settings | Access | Change During Run | Scaling | Size (Bytes) | CAN Register | CAN Sub Index | Modbus Register |
|---|---|---|---|---|---|---|---|---|---|---|---|
P6-11 | Speed Error Trip Level | % | 10.0% | 0.0 ... 100.0% | RW | Y | 1 = 0.1% | 2 | 2262h | 0 | 611 |
P6-12 | Speed Error Trip Detection Time | sec | 0.5s | 0.0 ... 5.0s | RW | Y | 1 = 0.1s | 1 | 2263h | 0 | 612 |
In open or closed loop operation this parameter defines the maximum permissible speed error (as % of the motor rated speed P4-06) between the Post-ramp Speed Controller Reference and the estimated rotor speed (open loop) or encoder feedback speed (closed loop) as calculated by the motor control algorithms. If the speed error exceeds this limit (for the time set in Parameter P6-12 Speed Error Trip Detection Time), the drive will trip Sp-Err.
Example below was on an application with a 1370 rpm rated speed motor, 0.3s detection time and a 0.1% speed error trip level, where 0.1% equates to 1.37rpm (0.001*1370rpm) for 0.3s after which the drive will trip Sp-Err.
In Closed loop operation this parameter defines the maximum permissible speed error between the encoder feedback speed value and the estimated rotor speed calculated by the motor control algorithms. If the speed error exceeds this limit (for the time set in Parameter P6-12 Speed Error Trip Detection Time) , the drive will trip Sp-Err.
Note
The Speed Error Trip does not operate (Function disabled) under the following conditions :
When P6-11 is set to zero
When motor control mode P4-01 is set to 2 (IM VF Mode)
While DC Injection is active.
Used in Conjunction with P6-11 (Speed Error Trip Level) to define to allowed time when the speed is above the value in P6-11 before tripping.
If the Speed Error Detection function is active then the fault code you will see if the Speed Error trips the drive is:
Display message | No. | Description | Corrective Action/Further information |
|---|---|---|---|
Sp-Err | 31 | Speed Error | Encoder Speed Error. The percentage error between the estimated (open loop)/measured encoder feedback speed and the actual motor speed is greater than the value set in P6-11 for the time set in P6-12.
Note: This fault is not active while DC Injection is active. |