Central Motion Control (PLC-Based)

With central Motion Control based on an AC500 PLC and PS552-MC the application program is done in the PLC but also the profile generator. The implementation of the profile generator is based on a set of Function Blocks which are named Compact Motion (CMC).

The profile generator of many possible axes is centrally placed inside the AC500 PLC. Therefore multiaxis motion functionalities become easily available and can be accessed by PLCopen Function Blocks. As a result, Motion Control functionalities are almost drive inpependent.

Available Motion Control functionalities:

• Simple axis Movements
• Electronic Gearin
• Electronic CAMs
• Position Profiles
• Velocity Profiles
• Acceleration Profiles
• Simple Movements in 3D
• Path Movements in 3D
• Kinematic Transformations for Roboitc Applications

Then the output is a position reference signal which the drive will follow. A new position reference value will be calculated with every cycle of the PLC and has to be transferred to the drive which demands real time capabilities to the PLC and to the communication channel. So, a real time fieldbus like ETHERCAT is needed. The feedback of the actual position can be used for supervision purposes during operation and is needed to adjust the value of the position reference before the drive will be enabled.

System structure of Central Motion Control with AC500 PLC and PS552-MC

With central Motion Control it is also possible to include the position control loop to the AC500 PLC. In this case a speed reference signal will be transferred to the drive which makes it possible to perform the full range of motion functionalities with standard drives. To close the position control loop a feedback of the actual position is mandatory.

Central Motion Control with AC500 PLC and PS552-MC, closed position control loop

Central Motion Control with AC500 PLC and PS552-MC, different axis implementations at the same time