
Table of contents
Inverter cabinet units
Operating Instructions, 12/2014, A5E32923362A 13
7 Functions ............................................................................................................................................ 335
7.1 Section content .....................................................................................................................335
7.2 Inverter control ......................................................................................................................335
7.2.1 Switching the motor on and off .............................................................................................335
7.2.2 Two-wire control, method 1 ..................................................................................................338
7.2.3 Two-wire control, method 2 ..................................................................................................339
7.2.4 Two-wire control, method 3 ..................................................................................................340
7.2.5 Three-wire control, method 1................................................................................................341
7.2.6 Three-wire control, method 2................................................................................................342
7.3 Setpoints ...............................................................................................................................343
7.3.1 Analog input as setpoint source............................................................................................344
7.3.2 Specifying the setpoint via the fieldbus.................................................................................344
7.3.3 Motorized potentiometer as setpoint source.........................................................................345
7.3.4 Fixed speed as setpoint source ............................................................................................347
7.4 Setpoint calculation...............................................................................................................349
7.4.1 Overview of setpoint processing...........................................................................................349
7.4.2 Invert setpoint .......................................................................................................................349
7.4.3 Enable direction of rotation ...................................................................................................350
7.4.4 Minimum speed.....................................................................................................................350
7.4.5 Skip frequency bands ...........................................................................................................351
7.4.6 Speed limitation ....................................................................................................................352
7.4.7 Ramp-function generator ......................................................................................................352
7.5 Motor control .........................................................................................................................356
7.5.1 Vector control or V/f control ..................................................................................................356
7.5.2 Closed-loop speed control ....................................................................................................357
7.5.2.1 Properties of the sensorless vector control...........................................................................357
7.5.2.2 Select motor control ..............................................................................................................358
7.5.2.3 Optimizing the closed-loop speed controller.........................................................................358
7.5.3 V/f control..............................................................................................................................360
7.5.3.1 Characteristics of V/f control.................................................................................................361
7.5.3.2 Selecting the V/f characteristic .............................................................................................362
7.5.3.3 Optimizing with a high break loose torque and brief overload..............................................363
7.6 Protection functions ..............................................................................................................364
7.6.1 Inverter temperature monitoring ...........................................................................................364
7.6.2 Motor temperature monitoring using a temperature sensor .................................................365
7.6.3 Protecting the motor by calculating the motor temperature..................................................368
7.6.4 Overcurrent protection ..........................................................................................................368
7.6.5 Limiting the maximum DC link voltage..................................................................................369
7.6.6 Minimum DC-link voltage limit ..............................................................................................370
7.7 Application-specific functions................................................................................................374
7.7.1 Unit changeover....................................................................................................................374
7.7.1.1 Changing over the motor standard .......................................................................................375
7.7.1.2 Changing over the unit system .............................................................................................376
7.7.1.3 Changing over process variables for the technology controller............................................377
7.7.2 Energy-saving display...........................................................................................................378
7.7.3 Braking functions of the converter ........................................................................................380
7.7.3.1 Electrical braking methods....................................................................................................380
7.7.3.2 DC braking ............................................................................................................................380
7.7.3.3 Dynamic braking ...................................................................................................................383