The SD4S is the first member of the SD4x frequency inverter family from Sieb & Meyer.

© Sieb&Meyer

The new frequency inverters support interfaces and protocols such as Profinet, TNC or BiSS. Their central feature is the significantly improved processor performance: The built-in 32-bit ARM Cortex M7 processor from NXP is up to five times faster than the processors of the SD2x frequency inverters, thus allowing higher resolution and more accurate calculations. In addition, Sieb & Meyer has switched from fixed-point math to floating point math, allowing a more flexible design. „Overall, more complex tasks can be processed more quickly with the new processor system,“ says Torsten Blankenburg, Chief Technology Officer at Sieb & Meyer. In addition, a new FPGA from Xilinx‘s „Spartan-7“ product line has been integrated: It enables more complex control tasks to be processed. Sieb & Meyer has also significantly increased its memory capacity compared to the members of the SD2x family - „with the 500 times larger memory, there will be no bottlenecks in the foreseeable future,“ says Blankenburg. „For the customer, this means a significant increase in performance: higher switching frequencies and improved control quality at even higher speeds lead to improvements in the overall process.

Thanks to an integrated position controller, the SD4x devices can also perform independent, high-precision positioning; speed and current controllers remain constant compared to the SD2x series. „Our aim is to drive high-speed motors dynamically and with as little power dissipation as possible,“ explains Blankenburg. „That‘s why we now also support PWM switching frequencies of 24 and 32 kHz.“ For even finer modulation of the sinusoidal signal, a commutation angle control is now also integrated for 32, 48 and 64 kHz. „This results in an almost optimal sine wave and virtually no harmonic currents,“ notes Blankenburg.

The new „drivemaster4“ version of Sieb & Meyer‘s parameterization software offers a four-part user interface. A watch list makes it possible to subscribe to the parameters of several devices simultaneously - „this is particularly useful for multi-axis applications“, as Blankenburg explains. Users can also use a data logger to view and evaluate characteristic curves over longer periods of time.

The SD4S is designed for small high-speed spindles and motors with a power range of just a few 100 W. Examples of applications are dental milling machines or machines for precision machining, such as those required in the watch industry. Because small spindles often do not have the necessary insulation strength in the motors, the SD4S now enables galvanic isolation of the thermal contact. Blankenburg regards the width of only 40 mm as an „absolute novelty“.  The SD4S is designed for use in a wide range of applications.

The parameters are set via a standard Ethernet interface, which replaces the USB interface, which is prone to failure in industry. In addition, the SD4S has parameterizable digital measuring system interfaces such as BiSS-C, EnDat2.2 and TTL. A web server enables technicians to call up device information without additional parameterization software. An incident can be synchronized via the real-time clock: For example, users can find out whether a thunderstorm has caused a failure.