Utilizing Scilab and Xcos for real-time control and measurement applications
By Grzegorz Skiba, Embedded Solutions
Nowadays Rapid Control Prototyping (RCP) has become a crucial method in developing and testing control strategies within time acceptable by the market. It is also a very popular technology in scientific and didactic laboratories. We want to present free Scilab module which can be used with Embedded Solutions MicroDAQ E1100/E2000 device for RCP as an alternative to expensive commercial software.
MicroDAQ module combines Scilab/Xcos environment with Embedded Solutions MicroDAQ real-time control measurement system equipped with TI C6000 DSP. Module extends Scilab by allowing user to automatically generate DSP applications directly from Xcos scheme. User can use custom Xcos MicroDAQ blocks (ADC, DAC, DIO, PWM, UART, Quadrature Encoder, TCP/UDP, To File) to create control and measurement applications. Generated DSP application utilizes SYS/BIOS real-time operating system combined with code generated from Xcos scheme. Depending on configuration, DSP application can be generated as a Standalone or Ext application (similar to External Mode in Matlab/Simulink). In Standalone mode generated application contains only real-time task, while in Ext mode code contains real-time task and low priority task which exchanges data with Scilab via TCP/IP protocol. Starting and stopping DSP application is integrated with standard Xcos Start/Stop buttons, module allows using standard sinks blocks to view live data from application running on DSP processor. Module allows to plot DSP execution profiles and generate DSP applications in „release” and „debug” mode.
Generated DSP application can be used with Scilab script. Module provides macros for loading generated DSP application, reading live data from running application and terminating DSP execution. Attached example shows how to use generated DSP application to compute FFT on data acquired from ADC input.
MicroDAQ module simplifies development of real-time control measurements applications, together with MicroDAQ hardware, platform gives out of the box experience and can be an alternative to expensive commercial systems. The system can be used for education on courses of Control Theory, Embedded Systems, DSP Processing, Real-Time Control and Mechatronics as an alternative to Matlab/Simulink. The system can be also applied in control system development for embedded platforms with TI DSP processors. Software is free of charge and will be available on ATOMS platform within two months.
Scilab, Xcos, Real-time processing, embedded system, DSP, code generation, rapid control prototyping, measurement systems, education, control, execution profiling, Scilab script
 Rapid Control Prototyping with Scilab/Scicos/RTAI for PC-based and ARM-based Platforms - https://fedcsis.org/proceedings/2008/pliks/157.pdf