Corrected from:
i700 servo inverter (no alteration in the i700)
(only the user interfaces of the engineering tools have been adapted, from PLC Designer V03.14)
Response of the new version:
Improved operation via the engineering tool dialogs (Easy Starter and PLC Designer) in the case described in this article. The user navigation has been improved.
The dialog for selecting the motor parameters for V/f operation has been provided with a button for preselecting the controller parameters.
In this way, the Imax controller settings will match the motor so that the described behaviour will no longer occur.
What happens?
The output frequency slowly continues to rise at standstill although no speed setpoint has been selected externally.
When does this behaviour occur?
The i700 servo inverter is operated in the 'V/f characteristic control' motor control mode (0x2C00=6), independently of the operating modes csv (0x6060=9) or vl (0x6060=2).
- The parameter settings of the maximum current limitation controller (Imax controller) have not been adapted to the motor so that the Imax controller parameters (0x2B08.x) are still in the default setting.
- After quick stop to standstill with intervention of the maximum current limitation.
The behaviour does not occur if the controller is inhibited for a short time after the motor has come to standstill.
Which products are affected?
i700 servo inverter
Short-term measures:
Provisionally, the behaviour may be avoided by slightly increasing the default setting of the Imax controller gain, e.g.: 0x2B08:1 = 1,000.
It will, however, be better to adapt the Imax controller settings to the motor. For this, proceed as follows:
- Go to the 'Motor commissioning' tab and manually enter the motor nameplate data of the asynchronous motor.
- Temporarily change the motor control mode to 'Servo control - asynchronous motor (ASM)' (0x2C00=2) and click the 'Estimate' button under 'Derived motor properties' to select the motor parameters 'Mutual inductance' and 'Rotor resistance'.
- Set the motor control mode again to V/f characteristic control (0x2C00=6) and click 'Initialize' on the 'Control/current' tab to select the parameters of the Imax controller.
Evaluation/recommendations:
When using Lenze motors, the motor parameters are usually selected from the motor catalog. In this case, different controller settings, including the Imax controller settings, will automatically be adapted to the motor.
Only when proceeding as follows during motor commissioning, the parameters of the Imax controller will still be in the default setting:
- The motor parameters are manually selected by entering the motor nameplate data (in particular for third-party motors) without
- selecting any further control parameter settings after this.
