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RT-DAC/PCI :  Applications  

There are two main application areas of theRT-DAC/PCI board. The first one uses the default

board configuration. The board can be applied as apart of a measurement and control systems. Theavailable by default inputs and outputs cover the viderange of digital and analog signal processingapplications, specially for mechatronic susyems. Theavailable software simplifies access to theRT-DAC/PCI board functions. The board can becontrolled by real-time applications (e.g. MATLABand RTW/RTWT toolboxes), laboratory measurementsoftware (e.g. LabView), industrial monitoring andcontrol packages (SCADA programs e.g. iFIX orInTouch) and even by such applications as MS-Excel.

The RT-DAC/PCI board is equipped with the XILINXFPGA chip. The logic of the FPGA can be reloadedby the user. This feature creates the secondapplication area of the board. The default logic canbe replaced by a used designed functions. Thereprogramming ability of the RT-DAC/PCI is aunique feature of the board.  The reprogrammingcan be performed unlimited number of times anddoes not require any hardware changes of the board.As an example the following new RT-DAC/PCI boardfunctions can be implemented:

• fast, hardware or software triggered, analog or

digital signals data acquisition into the internalmemory buffers,

• hardware-implemented analog signalgeneration,

• hardware-implemented digital filters of theanalog signals,

• hardware-implemented FFT,

• and others. Limit is the sky.

It is unique that all the functions of the board can beperformed much faster then implemented by othertechnologies. The data propagation from the input tothe output of the board depends only on the logic

configuration and typically is equal to 10-20nanoseconds. It is even 1000 times faster comparingto the microprocessor or DSP systems.

Control of the magnetic levitationsystem

The magnetic bearing keeps the shaft in the desiredcentral position by levitating in the magnetic field.There are several advantages of such approach. Forexample, absence of the friction allows higherrotating velocities comparing to the classical

bearings. The variable force generated by themagnetic bearing controller can reduce vibrations ofthe unbalanced rotating parts.

The disadvantage of the magnetic bearing system isthe sophisticated magnetic field controller. Thesatisfactory control results require that the magneticfield control is calculated a few thousand times persecond. Presented on the figure the magneticlevitation system consist of two magnetic bearingsand a DC drive which drives the shaft. The systemrequires eight PWM control waves to control thevalue and orientation of the magnetic field and asingle PWM signal to control the DC drive. It isrequired to measure nine current values, four analogsignals proportional to the position of the shaft and

the angle of the shaft. The angle of the shaft ismeasured by the incremental encoder.

The dedicated for the magnetic bearing system logicdesign supports all the functions required by themagnetic bearing system. The RT-DAC/PCI boardcan successfully control the system, creating low-cost alternative to dedicated DSP systems.

Control of the 3Dcrane system

The laboratory model of the 3D crane presents all

aspects of the real gantry crane system. The3-dimensional movement of the load generatesoscillations, which have to be dumped. The controllermust drive three drives. There are required positionmeasurements of each axis and two measurementsof the angle of the load. The RT-DAC/PCI logicdesign dedicated for the 3D crane model performs allthe required functions. The short response time of theFPGA chip allows the application of the board for thetime-critical safety functions. The FPGA hardwaredetects any exceeding of the 3D crane operatingrange and immediately cuts off the DC control. Alsothe FPGA chip sets the control to zero when the

temperature of the power amplifier exceeds safetyrange.

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Control of the engine

The modern methods of a fuel engine control requiremultipoint measurement system. The enginecontroller changes its parameters depending on thecurrent engine state. The controller measures theengine temperature and the position of the shaft andsets the air-fuel composition. The parameters of thecomposition are controlled by the accurate timings ofthe injection impulses. The control of the air-fuelcomposition requires also the generation of the

signals for the inlet and outlet valves. The preciseengine control requires that the control signals aregenerated fast and accurate. The accuracy of thesignals can not exceed a couple of microseconds anddepends on the shaft position.

The dedicated FPGA logic design for theRT-DAC/PCI board creates efficient laboratorycontrol system for the fuel engine. The parameters ofthe engine controller can be tuned from MATLABcommand window or from real-time Simulink models.The flexibility of MATLAB and Simulink environmentallow effective research work.

Control of the model of Anti-lockBreaking System

The Anti-lock Breaking System (ABS) is widely usedin modern car construction. The laboratory model ofthe ABS system allows to study the impulse breakingaspects. The model simulates the road, the car wheeland the break. The continuous or impulse control of

breaking can be tested. In the impulse breakingmode the controller must measure velocity of theroad, velocity of the wheel and control the breakingforce.

The velocities are measured by two incrementalencoders. The breaking force is controlled by PWMgenerator. The process is fast and requires very fastcontroller response. The dedicated FPGA logicperforms all time-critical tasks. The PC computer is asupervisor of the RT-DAC/PCI board and selects the

parameters of breaking mode. The computer alsoacquires real-time data and presents theexperimental results.

InTeCo Sp. z o.o.ul.Lea 203, 30-133 KrakówPoland

Tel./fax: (+48) 12 4304961Mobile. (+48) 601 536142

E-mail: inteco@kki.krakow.plhttp://www.inteco.cc.pl

RT-DAC – AP1/ENG- INTECO- 05/2002