The DDS Drive Series manufactured by Rexroth/Indramat are modular in design. The modular concept makes it possible to flexibly combine AC servo and main drives to create one compact drive package which uses one supply unit. In conjunction with a variety of electric automation motors, a basic DDS unit has the ability to solve multiple automation controlling desires if a specific option interface is installed onto the drive. The firmware fixes the functions of the drive. The DDS02.1 and DDS03.1 drives have a variety of options which can be explained through the part number itself. For example, they can have either external cooling, internal air cooling, or liquid cooling, a variety of power ratings starting at a base 15amp drive and then extending to 25,30,50,100,150 and ending with a 200amp drive, either a digital servo or resolver feedback for their motor feedback, or an analog interface which is indicated by an A in the part number, an Interbus-S interface, which is indicated by C, a Single axis position control interface, indicated by an L, or a SERCOS interface, indicated by an S.
DDS drives have ports which allows users to place custimzed communication modules or auxialry modules into the drive. The U1 port,found on the far left of the drive, is for command communication modules. The U2, U3, and U4 for DDS02.1 drives are for auxillary moules. The DDS03.1 drive has the communication port and only one U2 auxiliary port. The software module is inserted at the top of the drive here at the U5 slot. The firmware module is separate from the main unit itself. Firmware is continuously being updated, meaning the firmware version may increase indicated by a higher number on the firmware module itself.