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Hello. Brian Fortman here to give you an overview of another technology available as part of TI's Design Drive Position Manager Solutions for C2000 MCUs.

This time we're taking a top-level look at our SIN/COS solution. SIN/COS position sensing technology delivers analog signal feedback to your position controller. Like our other position manager technology, SIN/COS support, integrated on C2000 MCUs, reduces system costs and improves system performance by removing the need for an intermediate circuit to the controller and therefore reducing the feedback latency as well as reducing the chip count and system cost.

Beyond these fundamental benefits of Position Manager, the SIN/COS solution offers great precision over a wide speed range and robust feedback integrity through error detection and continuous calibration.

Importantly, it has been built for position control applications and can be tuned for your specific application. You can start your development today with a library that's been included in the C2000 Control Suite package.

The SIN/COS transducers are sometimes referred to as sinusoidal position encoders. The technique can be used standalone or incorporated into encoder interfaces like HIPERFACE or proprietary feedback interfaces.

In conventional quadrature encoders, angle information is obtained by counting the edges of paired quadrature pulses. Angular resolution is fixed by the number of pulses per mechanical revolution. However, in SIN/COS transducers, the precision of the angular measurement is increased by computing the angle between the edges using the relationship of a pair of sine and cosine outputs from the sensor.

SIN/COS sensors typically offer much higher rotary position resolution and higher maximum speed as compared to resolver or incremental encoders. Typically, several thousand electrical revolutions of the sinusoidal signals occur during each mechanical revolution of the encoder shaft.

Effectively, an interpolation between pulse edges is made to obtain a fine angle. The fine angle is computed using the arctangent of the two sinusoidal inputs. For this computation to be valid, both inputs must be sampled simultaneously.

The internal analog subsystem of C2000 MCUs, like the F2837x family, for example, is ideal for interfacing to SIN/COS transducers. The presence of multiple ADCs, which can be triggered from the same source, allows simultaneous measurements of both input channels.

In addition, the F2837x and 07x MCUs include a native arctangent instruction as part of the trigonometry math unit, or TMU, which means the angle calculation can be done in as little as 70 nanoseconds.

Another consideration is when operating at a high motor shaft speed. In this case, there is no longer a need for precise angle information, and the measurement algorithm only needs to count the number of completes sinusoidal revolutions to determine a course angle measurement.

Typically this is done using a pair of analog comparators which compare the incoming sinusoids with a threshold representing the 0 crossing point. The comparator outputs correspond to the sine of each sinusoid, and the resulting digital signals are similar to those produced by a quadrature encoder.

On the F2837x MCUs, there up to 8 analog comparators, each with its own programmable threshold voltage. These allow the quadrature pulses to be generated, which are then fed internally to one of the on-chip quadrature encoder peripheral modules for course angle and speed measurement.

For more information on how our solution optimally switches between high speed and low speed angle calculation, please refer to the SIN/COS Library Users Guide.

Here you see a simple block diagram of a SIN/COS position encoder sensor and its connection to a positioning controller. In this case, the acquisition and angle calculation is located inside of the F2837x real-time microcontroller from C2000.

You can also see that the only external components to the MCU that are required are the buffers and the power supply for the transducer itself. You can find these circuits clearly identified in the [INAUDIBLE] screen of the design drive development kit or IDDK.

To further support your SIN/COS circuit development, TI has also published a reference design in our TI Designs library.

The SIN/COS interface and the F2837x actually uses a combination of available resources on the device, including two ADC inputs, three comparator, a QEP, and some C28x megahertz. Note that in this case, the configurable logic block, or CLB, is not required.

As you can see, the C2000 on-chip peripheral resources really do make interfacing to SIN/COS sensors pretty easy. I do recommend reviewing the section on resource requirements in the SIN/COS Users Guide for more information.

As with all position manager releases, we've tested our solution on sensors from leading SIN/COS transducer suppliers like Lika. We have seen resolutions of 2.5 micro degrees and speeds up to 12,000 RPM.

The projects have all been built based on the IDDK Design Drive Development Kits available today in the TI store and are included in our Standard Control Suite software releases. The SIN/COS solution is made available at no charge through the Design Drive Development Kit and Control Suite.

For technical support on Position Manager solutions, please use our standard C2000 form at e2e.ti.com/c2000. And remember, it with C2000 Design Drive Position Manager and our SIN/COS solution, TI wants to help you spend more of your time differentiating your product and less of it developing or maintaining technologies that are quickly becoming table stakes in the industry.

Using Design Drive with ultimately help you get to market faster and with a more valuable product. For more information on Position Manager, Design Drive C2000 Real-time MCUs, or other TI solutions for industrial servo and drive control, please visit ti.com/tool/designdrive. Thank you.

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