Efficiency and flexibility are the most important factors in the development of new production machines. A key factor here is the drive technology and its integration into the machine process. According to a study, 7.6 servo drives are in use per machine - and the trend is rising [1]. As production machines are also becoming smaller and smaller, this trend is placing new demands on drive technology.

Sigmatek has designed its new generation of MDD 2000 Drives for dynamic multi-axis applications, which are frequently found in series machine construction. This is the latest member of the automation specialist's DIAS Drive series, which complements the servo systems in a higher performance range. To date, the S-DIAS family has comprised the modular MDD 100 series for up to eight servo axes per module and the compact SDD 300 series for the power range from 8 to 14 kVA and up to three drives.
The MDD 2000 series covers all of this in one series and expands it with modules with up to 30 A rated current or 60 A peak current per axis. When developing the new generation of drives, particular attention was also paid to creating a compact and flexible system with high power density and extensive safety functions. For example, the 3-axis device in size 1 with an output of 8.5 kVA measures just 75 mm × 240 mm × 219 mm, including power supply and mains filter. It is currently available with 3 × 5 A rated current and 15 A peak current. Depending on the number of axes, up to 10 A rated current and 25 A peak current will be possible in this size in the future. Size 2 is twice as wide at 150 mm and can handle up to 17.25 kVA. The 3-axis module with 3 × 10 A rated current and 30 A peak current is available for the market launch. Depending on the number of axes, up to 20 A rated current and 45 A peak current are planned for this size.

Modular multi-axis servo system

At market launch, the MDD 2000 series is available in sizes MDD 2100 and MDD 2200. The height and depth of the modules (240 mm x 219 mm) are identical, the width varies. Size 1 measures 75 mm and offers a connected load of up to 8.5 kVA per combined supply/axis module. The double-width size 2 provides up to 17.25 kVA.

© Sigmatek

A backplane was deliberately omitted from the design, eliminating the need to keep options on hand. Up to three axes are integrated in the combined MDP 2000 supply and axis module. This module can be used as a stand-alone compact drive or expanded with any MDD 2000 axis modules to form a multi-axis system.
multi-axis system. The user can choose between 1-, 2- and 3-axis modules in different performance classes and sizes. All modules can be connected to the 'DC Connection Block' (DCB) and 'Bus Connection Block' (BCB) without tools; there is no need for individual wiring for power, DC link coupling and real-time Ethernet communication. The servo system can be operated with single-phase or three-phase 380 - 480 AC; mains filter and braking resistor are integrated.

The new generation is cooled by fans as standard, which can be replaced without tools ; the drives are optionally available in a cold-plate version or as a through-hole variant. A brake voltage reduction can be configured to reduce the power loss or heat development in the holding brake of the motor.

More integrated safety

The MDD 2000 series from Sigmatek uses motors with single-cable technology Hiperface DSL encoders as standard.

© Sigmatek

In terms of safety, the MDD 2000 series has more safety functions than the MDD 100 and SDD 300 series. In addition to the Safe Torque Off (STO) and Safe Stop 1 (SS1) stop functions, Safe Operating Stop (SOS), the Safe Brake Control (SBC) brake function and the Safely-Limited Speed (SLS) speed function are integrated as standard and enable applications up to SIL 3, PL e, Cat. 4.
The implementation of the safety-relevant drive functions is flexibly solved: The controller enable by the central safety controller can be hard-wired as before via the six integrated enable inputs or now via the Varan real-time Ethernet bus. The safety functions can be parameterized in the safety controller, while the set parameters are monitored in the drive.

Single-cable solution as standard

The new Servodrive generation uses the Hiperface DSL digital motor feedback interface as standard. The single-cable solution for power and feedback signals eliminates the encoder cable and minimizes the cabling effort. In addition to the single-cable solution, the encoder variants EnDat 2.1 and 2.2, Hiperface, Resolver, Sin/Cos, TTL, BiSS-C, SanyoDenki and Tamagawa are also supported.
The position is specified in the controller and is transmitted to the drive via the Varan Ethernet bus
system Varan to the drive. The controller cycle times are 62.5 µs. To avoid unnecessary overhead, the functions of the servo system are limited to current, speed and position control. The positioning and control algorithms are executed by the controller integrated in the drive, which also communicates with the higher-level control system and ensures fast data traffic. Six integrated digital capture inputs enable the position to be saved in the µs range. Three two-channel safe 24 V inputs are also available, which can be configured for specific applications.