Lenze is combining processing power with smart program modules to control application-specific machinery.
Design News: How does Lenze regard the future of automation from a drives and control perspective?
Jendryschik: Every machine needs special control functions. Lenze, therefore, is focusing on what we call technology functions. These are pre-programmed function blocks specifically designed for the application. Examples might be packaging, printing, or other positioning systems. Such function blocks, installed and run on the company's 9300 Servo PLC and the Drive PLC, describe the machine's process to aid the engineer in optimizing its control.
Q: What was the genesis of this program?
A: The first step was to combine the control system and inverter into one unit: the 9300 Servo PLC. This product proved that a system can be run without a host PLC. What is more, the inverter can be programmed in accordance with IEC 1131. What was a success for high-end applications then became available for the compact class of frequency inverter: the Drive PLC, a special control system for the frequency inverter series 8200.
Q: Please explain how the Drive PLC works.
A: With the Drive PLC it is possible to have as many as 512 inputs and outputs in addition to the usual drive technology interfaces. Application modules optimized for control functions close to the drive are simply push-fit onto the Drive PLC, making an ideal control unit for smaller machines and machine segments.
Q: How is software aiding the design process?
A: Lenze Drive Design software helps the engineer configure the drive in total. The new software contains a database of all Lenze products that could be combined into a drive system. The engineer simply enters the process parameters; the software configures the appropriate system components and brings the parameter sets into the controller.
Q: What role does communication play in advancing motor control?
A: The trend in machinery is to separate all mechanical motions into independent axes and to synchronize all motion through a network. Because any interrupt in communication between axes is unacceptable, the network must be very reliable and fast. Lenze uses the CAN bus system, proven by the automotive industry, for low-level communications. For higher-level communications, our products are open to most popular protocols. And, with the new range of Lenze drive systems, one can even apply two different communication plug-ins. This permits use of the drive as a gateway between, say, InterBus and DeviceNet.
Q: Please explain further.
A: Consider a scenario where there is a machine set up with multiple drives, and the user wants to run the entire setup with the InterBus protocol, for example. With separate communication plug-ins, the user can connect one drive to the InterBus and connect the other drives through the on-board CAN bus. That means that the data comes in on the InterBus, is converted to CAN bus data, and is then sent to the other drives over the CAN bus. Since the CAN bus is already on-board, the price of a communications module is saved.
Q: Beyond pre-programmed function blocks and configuration software, what is the next step in motor control?
A: Precision versus price is the issue, which means sensorless vector control. It's much less expensive to run a sensorless system than to pay for the feedback loop, wiring, and work of setting up a vector controlled system with feedback, or a servodrive. Also, a sensorless vector system is more reliable due to fewer parts. But software is still involved. Such systems will become more competitive as better algorithms improve accuracy to where sensorless vector control can maintain torque on the motor shaft at low, and even down to zero, speed.
Jürgen Jendryschik graduated from Berlin Technical University and postgraduated at Hanover University, specializing in vibration control. He served for Dräger Medical in Germany in MIS (CIM-Projects) before joining the Lenze Group in 1990. At Lenze, Jendryschik has worked in several fields like MIS, gearmotors, and sales. The past 4 years he has been in charge of U.S. business as Chairman of Lenze Corp./New Jersey, with a focus on American and Asian Markets.