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Topic: Digital control


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  Digital Power Control
Digital signal controllers enable drives for permanent magnet synchronous motors to be optimized with complex algorithms at low cost.
Despite obvious advantages over analog controllers, the limited power of today's digital controllers requires careful measuring techniques to accurately capture the real-time response of the control loop....
Digital power solutions make it possible to measure power-stage frequency response in the application, opening the door to new capabilities such as auto-tuning, power-stage diagnosis and on-the-fly adaptability....
powerelectronics.com /power_management/digital_power_control   (712 words)

  
  Digital control - Wikipedia, the free encyclopedia
Digital control is a branch of control theory that uses digital computers to act as a system.
Since a digital computer is a discrete system the Laplace transform is replaced with the Z-transform.
The need/use of digital control can readily be understood in the use of feedback.
en.wikipedia.org /wiki/Digital_control   (314 words)

  
 Digital Command Control - Wikipedia, the free encyclopedia
Digital Command Control (DCC) is a scheme for controlling locomotives on a model railroad layout that allows one or more locomotives to be independently controlled on the same electrical section of track.
Each of the locomotives is equipped with a mobile decoder/receiver that receives signals from the track and provides power to the motor and any lights the model may have.
There are several competing digital train control systems, most notably the European standard, Selectrix, and the proprietary Märklin-Motorola system, which is used exclusively in the model train products of Märklin company.
en.wikipedia.org /wiki/Digital_Command_Control   (593 words)

  
 Elements of a Direct Digital Control System   (Site not responding. Last check: 2007-09-25)
Digital outputs (DO) are typically used to provide on/off control of valves, dampers, electric motors, lighting and external signaling devices, such as alarm bells and indicator lights.
Two-position actuators are used to control the linear or rotary motion of a controlled device (such as a valve or damper) to one of two positions, usually open or closed.
The solenoid is used to control the internal flow of the pilot fluid within the valve, causing the operation of the valve.
www.energy.iastate.edu /ddc_online/inout/inout_chapt03_digitaldev.html   (1303 words)

  
 Audio Gain Control Using Digital Potentiometers - Maxim/Dallas
Over the past few years, digital potentiometers have become available, using resistive ladders and FET switching under digital control to effectively replace mechanical potentiometers in a number of areas.
A second issue is that while the digital pot steps are usually designed to give equal value resistive increments, a by-product of the process variation is that the total end-to-end resistance varies widely from part to part - as much as ±30% in some types.
The two disadvantages of applying this with a 'linear' digital pot is that the input impedance of the pot is now dependant on gain setting (lowest at max.volume), and (again) the wide tolerance on end-to-end resistance means L-R tracking suffers at any setting apart from the extremes.
www.maxim-ic.com /appnotes.cfm/appnote_number/1828   (2077 words)

  
 Digital Speed Controller using RTAI/Linux LG #118
A controller is a device introduced into the system to sense the error signal and to produce the required control signal.
An automatic controller compares the actual value of the plant output with the desired value, determines the deviation, and produces a control signal which will reduce the deviation to zero or to a smaller value.
The controller program produces the necessary actuating signal (in terms of a PWM pulse), which in turn depends on an error signal produced by the difference of the set speed (a constant in the program) and the present speed.
linuxgazette.net /118/sreejith.html   (2963 words)

  
 A DIGITAL SIGNAL PROCESSOR BASED RF CONTROL SYSTEM FOR THE TRIUM
The digital signal processor is used as a feedback controller during CW rf operation, with the feedback gain parameters continually adjustable.
With the DSP controlling both the duty cycle and the regulation of the rf, amplitude regulation is possible both in CW mode and in pulse mode.
For the RFQ prototype control system, the dynamic range as well as the resolution of the feedback signal is enhanced by extracting the error signal in analog form as a voltage using a difference amplifier.
linac96.web.cern.ch /Linac96/Proceedings/Tuesday/TUP42/Paper.html   (2069 words)

  
 Multi-Rate Digital Control   (Site not responding. Last check: 2007-09-25)
Figure 1 is a typical single-input single-output (SISO) digital control system, which has a digital controller and a controlled plant.
In this case, digital control with a standard zero order hold may not be appropriate, and it has been suggested to update the control input at a higher rate.
Another reason for using multi-rate control may be that the sampling rate is constrained by the computational speed of microprocessors for digital control.
mechatro2.me.berkeley.edu /research/disk/yuping.html   (388 words)

  
 LC&D: GR 2400 System - Overview
Scalable means that the same relay panels, digital switches and accessories are specified and installed in both the smallest and largest applications.
Digital photocells provide 14 different trigger points each controlling a unique relay group.
Unity™ Lighting Control Software Lighting Control Software bundles design (specification), programming and management of a lighting control system into a single software package.
www.lightingcontrols.com /design/innovative/gr2400/index.asp?b=5&l=32   (440 words)

  
 CTMS: Digital Control Example: Cruise Control: Root-Locus
In this digital control version of the cruise control problem, we are going to use the root-locus design method to design the digital controller.
Recall from the continuous Cruise Control: Root-Locus page, the lag controller was added to the system to obtain the desired response.
There is a guideline to design digital lead and lag compensators and a guideline for design continuous time lead and lag compensators.
www.library.cmu.edu /ctms/ctms/examples/cruise/digccrl.htm   (990 words)

  
 Direct Digital Control Energy Management System   (Site not responding. Last check: 2007-09-25)
Some systems require humidity and/or exhaust fan control, as well as energy recovery (using the available heating/cooling from the exhaust air to heat/cool the outside air that is being drawn into the building by the supply fans).
When global information is required for control (such as outside air temperature/humidity), the host computer passes the information to all locations on campus to ensure that all receive the same information.
In addition, DDC has replaced pneumatic controllers that tend to drift out of calibration and suffer from "offset" (i.e., the pneumatic controllers don't have the ability to maintain the temperature at setpoint under changing load conditions).
www.p2000.umich.edu /energy_conservation/ec5.htm   (660 words)

  
 Digital / analog motor control systems - complete, integrated control solutions from Texas Instruments
As the trend for control systems requires them to incorporate more advanced features and functionality, Texas Instruments delivers the solutions that allows designers of white goods, automotive and industrial motor drives to implement the most advanced, integrated and cost-efficient control systems.
Our broad base of control-optimized digital signal controllers combines TI's leading digital signal processing technology (DSP) for the industry's highest level of optimized performance with the control peripherals and ease of use of traditional microcontrollers.
This unique combination of performance and control cuts costs down to unprecedented levels while delivering higher motor efficiency, quieter operation, lower energy consumption and greater reliability compared to conventional microcontroller solutions - all with fewer external components, reduced system costs and amazingly small packages that are great for space-constrained designs.
focus.ti.com /docs/apps/catalog/overview/overview.jhtml?templateId=1050&path=templatedata/cm/level1/data/dctrl_ovw   (218 words)

  
 DPS   (Site not responding. Last check: 2007-09-25)
Figure 3: Replacing R1 with a digital potentiometer causes the phase shift the circuit realizes to be under digital control.
Dual, quad, or hex digital potentiometers can be used to control all sections under control of a microprocessor, as shown in the phase shifter/stereo synthesizer example of Figures 4-8.
The DS1806 hex digital potentiometers' wiper positions are under control of a simple three-wire digital interface, which clocks the wiper position settings into the device over its DQ line, while the /RST line is high.
www.web-ee.com /Schematics/Digital_Phase_Shifter/dps.htm   (565 words)

  
 Metering pumps for precision dispensing and dosing. Digital control for laboratory and manufacturing. Metering pump, ...
The pump and associated equipment require calibration, and a method for controlling the system must be established.
Valves to prevent inaccuracy due to fluid drift within the pump, and reservoirs or dampeners for pulsation reduction are often necessary as well.
Equipment calibration is not required because flow rate is not dependent on the stroke length of the piston, as is the case for many traditional metering pumps.
www.encynova.com   (289 words)

  
 ColorVision Europe - Affordable Solutions For Digital Color Control
Digital photography has become child’s play, thanks to lenses with lighting focus and automatic programs that can control any lighting situation.
From a technical viewpoint, this is hardly surprising: three different devices are working together, none of which has been calibrated to the other.
This is the color space of light in which the human eye breaks down the colors it sees into red, green and blue elements, before our brain puts them back together again into a perceived color.
www.colorvision.ch /learnmore   (644 words)

  
 Digital Volume Control   (Site not responding. Last check: 2007-09-25)
Circuit of a digital volume control using six discrete ICs, including a 5V regulator, is presented.
In the circuit, IC4 is used as a potentiometer by connecting 15 resistors (R9 through R23) between each of its 16 input pins and a resistor/capacitor combination of C2, C3 and R7 at its output.
The volume control circuit of right channel will be identical to that of the left channel circuit (shown here) except that IC1, IC5 and push-to-on switches are not to be duplicated.
www.electronics-lab.com /projects/audio/010   (397 words)

  
 Shimano Calcutta TE DC (Digital Control) Baitcast Reels
With the digital braking technology employed by Calcutta TE DC, it is possible to allow spool Rotation to exceed 30000rpm (50-70% increase) and still maintain excellent line control for longer, more accurate casts.
Based on a 6-second duration cast, the digital technology behind the DC digital braking systems allows the brakes to be applied in intervals of up to 1/1000 second.
Subsequently, digital control varies the frequency of the brakes applied, minimizing the dreaded backlash.
www.landbigfish.com /tacklestore/showcase.cfm?PID=1533&SiteID=1212&AID=1212   (726 words)

  
 Digital Electronic Control
Besides flexible control of lighting and HVAC systems, DDC can also integrate fire and intruder alarms, security and access systems and local and wide area computer networks.
Even in retrofit situations with existing pneumatic controls, it is usually worth examining the use of zone or central digital controllers.
Often DDC zone controllers are suitable and economic for small applications with fewer than 16 inputs and outputs.
greenbuildings.santa-monica.org /controlsys/energydemand.html   (608 words)

  
 Indexing System has all-digital servo control., Hardinge Inc.
This current generation digital control has an intelligent power module (drive electronics) for cooler and quieter operation resulting in a highly efficient system.
Hardinge’s servo control features a multiple line LCD display that lets the user view and edit the program number, step number, loop count and preparatory code on the top two lines of the display, eliminating scrolling.
The Hardinge servo control can be used as a direct replacement for the current benchmark control in conjunction with either brush or brushless motor indexers.
news.thomasnet.com /fullstory/455360   (970 words)

  
 Introduction to Pulse Width Modulation - PWM, control systems, digital control
As intuitive and simple as analog control may seem, it is not always economically attractive or otherwise practical.
One of the advantages of PWM is that the signal remains digital all the way from the processor to the controlled system; no digital-to-analog conversion is necessary.
The output of a PWM controller could be connected to a switch between the supply and the brake.
www.netrino.com /Publications/Glossary/PWM.html   (1277 words)

  
 Model Railroading with Digital Command Control
This is the general scheme of controlling the magnetic devices like turnouts, signals etc. of a scale Z (mini-club) train via Märklin's DIGITAL devices and a Personal Computer.
Note that Märklin no longer supports/recommends using its current DIGITAL devices for scale Z. This was not always the case: Around 1987 they included detailed hints how to control Z turnouts, signals, etc. in their book about Digital control, using the same Digital control system as for their H0 scale products with 3-rail AC power.
Some time later Märklin announced a special version of its Digital control system for 2-rail DC systems, and that it would be available for scale N (from Arnold) and for scale Z later.
www.geocities.com /SoHo/Suite/7013/train   (997 words)

  
 DCC Standards, A Non-Technical Discussion
The recent blitz of command control articles has left some of us ordinary folks overwhelmed by new concepts and terms such as digital packets, time-division multiplexing, bits, stretched bits, single-chip microcontrollers, and bi-polar digital control signals.
Perhaps the single greatest appeal to using microprocessors in locomotives and a digital control signal is the ability to run NMRA-conforming receiver-equipped locomotives on a conventional 12 volt DC layout without any modifications whatsoever.
The control signal (waveform shape) is being standardized, but not the equipment used to create/transmit/receive/decode the control signal.
www.tttrains.com /dcc/dccntd.htm   (2038 words)

  
 CTM: Digital Control Example: Cruise Control: Root-Locus   (Site not responding. Last check: 2007-09-25)
The system having this large gain (too much control effort) might not be available in a real physical system, even though it is possible in the Matlab simulation.
There is a guideline to design digital lead and lag compensators.
Recall from your control textbook, the gain (K) equals 0 at poles and infinity at zeros.
www.engin.umich.edu /group/ctm/examples/cruise/digCCRL.html   (993 words)

  
 E-Z Command Digital Command Control System FAQ   (Site not responding. Last check: 2007-09-25)
These standards define a standard method for the digital signals that are sent over the rails for the purpose of controlling model railroads.
E-Z Command® and Bachmann Digital on Board locomotives have been extensively tested by the NMRA and is certified to meet and conform with all of it's standards and recommended practices for digital command control.
When this is done the analog throttle controls the non decoder equipped locomotive and Button 10 controls a digital locomotive with the address of 10.
www.bachmanntrains.com /home-usa/ez/ez4.php   (2063 words)

  
 digital multiplexor for remote control logic or distributed control with analog inputs for temperature sensors, ...
Controls for mobile equipment and industrial automation, power conversion for power generators, controls for utility and marine applications.
As an alternative to analog amplifiers and control cards, digital controllers use microprocessing power to replace adjustment potentiometers and other selection components that take up valuable space on the hardware.
The digital controllers close the loop on external sensor inputs, gear tooth sensors, pressure transducers and other inputs for position, temperature and/or speed control.
www.axiomatic.com /digital.html   (1233 words)

  
 CTM Example: Digital DC Motor Speed Control with PID Control   (Site not responding. Last check: 2007-09-25)
A digital DC motor model can be obtained from conversion of the analog model, as we will describe.
The controller for this example will be designed by a PID method.
The first step in designing a discrete control system is to convert the continuous transfer function to a discrete transfer function.
www.engin.umich.edu /group/ctm/examples/motor/digital.html   (991 words)

  
 Logitech Products > Speakers > Logitech® Z-5500 Digital
The result is the Logitech Z-5500 Digital, a THX-certified, 500-watt 5.1 surround sound speaker system that offers everything you could possibly want… and some things you didn't even know you needed.
Digital equalization: The Z-5500 Digital actively adjusts frequency response in real time for the cleanest, most accurate sound reproduction.
The Z-5500 Digital is one of a select few speaker systems that meets the rigid standards for unparalleled THX-quality sound.
www.logitech.com /index.cfm/products/details/US/EN,CRID=2,CONTENTID=9486   (724 words)

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