Siemens SINAMICS G120 CU240E-2 - Page 7

Table of contents
Inverter with CU240B-2 and CU240E-2 Control Units
Operating Instructions, 07/2010, FW 4.3.2, A5E02299792B AA
7
6.3.4 Acyclic communication...............................................................................................................123
6.3.4.1 Acyclic communication over PROFIBUS DP (DP V1) ...............................................................123
6.3.5
STEP 7 program examples........................................................................................................124
6.3.5.1
STEP 7 program example for cyclic communication .................................................................124
6.3.5.2
STEP 7 program example for acyclic communication ...............................................................126
6.4
Communication via RS485 ........................................................................................................130
6.4.1
Integrating inverters into a bus system via the RS485 interface ...............................................130
6.4.2
Communication via USS ............................................................................................................131
6.4.2.1
General information about communication with USS via RS485 ..............................................131
6.4.2.2
Structure of a USS telegram......................................................................................................133
6.4.2.3
User data range of the USS telegram........................................................................................135
6.4.2.4
Data structure of the USS parameter channel...........................................................................135
6.4.2.5
USS read request ......................................................................................................................140
6.4.2.6
USS write job .............................................................................................................................140
6.4.2.7
USS process data channel (PZD)..............................................................................................141
6.4.2.8
Telegram monitoring ..................................................................................................................142
6.4.3
Communication over Modbus RTU............................................................................................144
6.4.3.1
Parameters for Modbus communication settings.......................................................................144
6.4.3.2
Modbus RTU telegram...............................................................................................................146
6.4.3.3
Baud rates and mapping tables .................................................................................................147
6.4.3.4
Write and read access via FC 3 and FC 6.................................................................................150
6.4.3.5
Communication procedure.........................................................................................................152
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Functions............................................................................................................................................... 155
7.1
Overview of the inverter functions..............................................................................................155
7.2
Inverter control ...........................................................................................................................157
7.3
Command sources.....................................................................................................................158
7.4
Setpoint sources ........................................................................................................................159
7.4.1
Selecting the setpoint source.....................................................................................................159
7.4.2
Analog input as setpoint source.................................................................................................160
7.4.3
Motorized potentiometer as setpoint source..............................................................................160
7.4.4
Fixed speed as setpoint source .................................................................................................163
7.4.5
Running the motor in jog mode (JOG function) .........................................................................165
7.4.6
Specifying the motor speed via the fieldbus ..............................................................................166
7.5
Setpoint calculation....................................................................................................................166
7.5.1
Minimum speed and maximum speed .......................................................................................166
7.5.2
Ramp-function generator ...........................................................................................................167
7.6
Motor control ..............................................................................................................................168
7.6.1
V/f control...................................................................................................................................169
7.6.1.1
V/f control with linear characteristic ...........................................................................................170
7.6.1.2
Additional characteristics for the V/f control...............................................................................171
7.6.1.3
Optimizing with a high break loose torque and brief overload...................................................172
7.6.2
Vector control.............................................................................................................................173
7.6.2.1
Properties of vector control........................................................................................................173
7.6.2.2
Commissioning vector control....................................................................................................173
7.6.2.3
Torque control............................................................................................................................174
7.7
Protection functions ...................................................................................................................175
7.7.1
Inverter temperature monitoring.................................................................................................175
7.7.2
Motor temperature monitoring using a temperature sensor ......................................................176
7.7.3
Protecting the motor by calculating the motor temperature.......................................................178
7.7.4
Overcurrent protection ...............................................................................................................178
7.7.5
Limiting the maximum DC link voltage.......................................................................................179