Meets most absolute encoder transmission requirements
3 reference designs provided

Texas Instruments provides the DesignDRIVE Position Manager solution for major analog and digital position sensor interfaces that are currently widely used, to support designs using the C2000 Delfino TMS320F28379D and TMS320F28379S MCUs and the upcoming F280049C and F280041C.
Industrial drive designers no longer need to directly develop sine/cosine, resolver, and absolute encoder controller interfaces for EnDat, BiSS (bidirectional/serial/synchronous), and T-Format. This position manager solution achieves improved feedback performance and lowers system costs by integrating various functions. It improves the timing of key current, speed, and position loops by reducing latency. Furthermore, costs are further reduced by moving digital logic to the MCU, thereby shrinking the size of the FPGA that previously housed the encoder interface logic.

To date, TI has developed a position manager solution for use with the DesignDRIVE development kit hardware. While this development kit is a robust servo drive reference design, TIDM-SERVODRIVE is designed to evaluate and test current detection, position feedback, and power topologies. Interfacing solely with position feedback sensors can result in a somewhat expensive evaluation platform. However, the new Position Manager BoosterPack module utilizes the C2000 solution to provide an affordable solution for evaluating interfaces with absolute encoders as well as sine/cosine and resolver sensors.

This BoosterPack hardware includes RS-485 interfacing circuitry, meeting most absolute encoder transmission requirements. In fact, this board contains two SN65HVD78 devices supporting a 100m cable length. The position encoder interface reference design adopting EnDat 2.2 includes test results such as maximum frequency, jitter, and propagation delay relative to cable length. If long-distance RS-485 communication is required but a position manager solution is not strictly necessary, this new BoosterPack hardware can be used.

As shown in Figure 2, this board includes a signal conditioning circuit for analog sine/cosine signals.
The C2000 Position Manager SinCos library was released for the TMS320F2837x family, but it can be used with almost any C2000 MCU capable of sampling two analog signals simultaneously. By using existing libraries, new BoosterPack modules, and compatible C2000 LaunchPad™ development kits, you can easily develop the desired sine/cosine transducer interface. A CLB (configurable logic block) capable C2000 MCU is not strictly necessary to use sine/cosine solutions. However, using a CLB-capable product allows for the simultaneous execution of sine/cosine and absolute encoder interfaces.

To enable you to quickly develop your desired project using the Position Manager Booster Pack module, three reference designs from the TI Designs Reference Design Library are provided.

▲ EnDat 2.2 Absolute Encoder Master Interface Reference Design for C2000 MCU ▲ BiSS-C Absolute Encoder Master Interface Reference Design for C2000 MCU ▲ Tamagawa T-Format Absolute Encoder Master Interface Reference Design for C2000 MCU

These reference designs include schematics, layouts, BOMs, and design guides, allowing for quick and easy integration with industrial drives or servo drives. Software projects to support EnDat, BiSS, and Tamagawa T-Format with this new Booster Pack hardware are provided through the C2000 controlSUITE package or the design kit provided with this reference design.

Further details regarding the DesignDRIVE Position Manager solution for C2000 MCUs can be found at the following link:

▲ TI DesignDRIVE Training Portal ▲ DesignDRIVE Application Portal ▲ Blog: Designing Interfaces to Meet EMC Requirements with Motor Position Encoders ▲ White Paper:Next-generation industrial drive and control system design

This article is based on a contribution from Texas Instruments.