Digital Control Library (DCL)

Table of Contents

• Introduction
• Features Supported
• Features Not Supported
• Benchmark Results
• Provided Examples
• Additional References
• API

Introduction

The Sitara™ Digital Control Library (DCL) provides a suite of robust software functions for developers of digital control applications using the Texas Instruments Sitara MCU. DCL is a header-only library, and all functions in the library are provided in the form of C source-code.

The DCL contains PI,PID and "Direct Form" controller types. The former are typically used to tune properties of a transient response, while the latter are typically used to shape the open loop frequency response.

In addintion, DCL contains functions to convert controller parameters from one type to the other. As well as functions to parameterize the controller given a transfer function.

Several utility modules such as error handling, data logging are also included as a supporting module.

Features Supported

Supported controller modules (floating-point)

• Linear PI
• Linear PID
• Linear PI with double integrator (PI2)
• Direct Form 1 (first order)
• Direct Form 1 (second order)
• Direct Form 1 (third order)
• Direct Form 2 (second order)
• Direct Form 2 (third order)
• Non-linear PID controller

Other utility modules:

• Error Handling
• Testpoints
• Data Logging
• Multi-channel data logs
• Reference Generator and performance index

Features Not Supported

N/A

Benchmark Results

A benchmark on R5F core has been conducted to observe the following results when running controller arithmetic:

Controller Function	Cpu Cycles
PI Controller
DCL_runPISeries	49
DCL_runPIParallel	50
DCL_runPISeriesTustin	56
DCL_runPIParallelEnhanced	62
PI2 Controller
DCL_runPI2Series	74
PID Controller
DCL_runPIDSeries	65
DCL_runPIDParallel	65
DF11 Controller
DCL_runDF11	24
DF13 Controller
DCL_runDF13	43
DCL_runDF13Clamp	53
DF22 Controller
DCL_runDF22	27
DCL_runDF22Clamp	41
DF23 Controller
DCL_runDF23	29
DCL_runDF23Clamp	45
PID 64bit Controller
DCL_runPIDF64Series	185
DCL_runPIDF64Parallel	174

• Ran with TI Clang Compiler v2.1.3.LTS, with -Os flag and all DCL functions inlined, obtained the average result from 600 consecutive reading of running the controller with DPL CycleCountP.
• Simulated inputs are based on arbitrary sinusoidal waves and saturation condition that roughly clamps ~50% of the time. For functions with clamp (PI,PI2,PID and DF Clamps), clock cycle varies depending on clamping condition and provided inputs.
• Actual result may vary depending on provided datasets and memory configuration. For R5F, it is recommended for users to map control loops to TCM for the best performance.

Provided Examples

The following examples has been provided to demonstrate the DCL library:

• DCL PI Test
• DCL DF22 Test

Additional References

N/A

API

APIs for Digital Control Library