user_intro.lyx

CNC 的开放码,EMC2 V2.2.8版

#LyX 1.3 created this file. For more info see http://www.lyx.org/
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\layout Chapter

EMC2
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\series bold 
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The Enhanced Machine Control
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This Manual
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The focus of this manual is on using EMC.
 It is intended to be used once EMC is installed and configured.
 For standard installations see the Getting Started Guide for step by step
 instructions to get you up and going.
 For detailed information on installation and configuration of EMC see the
 Integrator Manual.
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How EMC2 Works
\begin_inset LatexCommand \label{sec:How-EMC2-Works}

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The Enhanced Machine Controller (EMC2) is a lot more than just another CNC
\begin_inset LatexCommand \index{CNC}

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 mill program.
 It can control machine tools, robots, or other automated devices.
 It can control servo motors, stepper motors, relays, and other devices
 related to machine tools.
 
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There are four main components to the EMC2 software: a motion controller,
 a discrete I/O controller, a task executor which coordinates them, and
 user interfaces.
 In addition there is a layer called HAL (Hardware Abstraction Layer) which
 allows configuration of EMC2 without the need of recompiling.
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Figure 
\begin_inset LatexCommand \ref{fig:Typical_machine}

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 shows a simple block diagram showing what a typical 3-axis EMC2 system
 might look like.
 This diagram shows a stepper motor system.
 The PC, running Linux
\begin_inset LatexCommand \index{Linux}

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 as its operating system, is actually controlling the stepper motor drives
 by sending signals through the printer port.
 These signals (pulses) make the stepper drives move the stepper motors.
 The EMC2 can also run servo motors via servo interface cards or by using
 an extended parallel port to connect with external control boards.
 As we examine each of the components that make up an EMC2 system we will
 remind the reader of this typical machine.
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\begin_inset LatexCommand \label{fig:Typical_machine}

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Simple EMC2 Controlled Machine
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Graphical User Interfaces
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A graphical interface is the part of the EMC2 that the machine tool operator
 interacts with.
 The EMC2 comes with several types of user interfaces: 
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Axis an OpenGL-based GUI, with an interactive G-Code previewer.
 This is the only interface that is currently being developed and improved
 on.
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	lyxscale 80
	scale 80

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Keystick a character-based screen graphics program suitable for minimal
 installations.
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Xemc an X Windows program
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two Tcl/Tk-based GUIs named tkemc and mini
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Thinking Like a Machine Operator
\begin_inset LatexCommand \label{sec:Thinking-Operator}

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This book will not even pretend that it can teach you to run a mill or a
 lathe.
 Becoming a machinist takes time and hard work.
 An author once said, 
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We learn from experience, if at all.
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 Broken tools, gouged vices, and scars are the evidence of lessons taught.
 Good part finish, close tolerances, and careful work are the evidence of
 lessons learned.
 No machine, no computer program, can take the place of human experience.
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As you begin to work with the EMC2 program, you will need to place yourself
 in the position of operator.
 You need to think of yourself in the role of the one in charge of a machine.
 It is a machine that is either waiting for your command or executing the
 command that you have just given it.
 Throughout these pages we will give information that will help you become
 a good operator of the EMC2 mill.
 You will need some information right up front here so that the following
 pages will make sense to you.
 
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Modes of Operation
\begin_inset LatexCommand \label{sub:Modes-of-Operation}

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When an EMC2 is running, there are three different major modes used for
 inputting commands.
 These are Manual
\begin_inset LatexCommand \index{Manual}

\end_inset 

, Auto
\begin_inset LatexCommand \index{Auto}

\end_inset 

, and MDI
\begin_inset LatexCommand \index{MDI}

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.
 Changing from one mode to another makes a big difference in the way that
 the EMC2 behaves.
 There are specific things that can be done in one mode that can not be
 done in another.
 An operator can home an axis in manual mode but not in auto or MDI modes.
 An operator can cause the machine to execute a whole file full of G-codes
 in the auto mode but not in manual or MDI.
 
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In manual mode, each command is entered separately.
 In human terms a manual command might be 
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turn on coolant
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 or 
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jog X at 25 inches per minute.
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 These are roughly equivalent to flipping a switch or turning the hand wheel
 for an axis.
 These commands are normally handled on one of the graphical interfaces
 by pressing a button with the mouse or holding down a key on the keyboard.
 In auto mode, a similar button or key press might be used to load or start
 the running of a whole program of G-code that is stored in a file.
 In the MDI mode the operator might type in a block of code and tell the
 machine to execute it by pressing the <return> or <enter> key on the keyboard.
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Some motion control commands are available and will cause the same changes
 in motion in all modes.
 These include 
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abort
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, 
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estop
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\begin_inset LatexCommand \index{ESTOP}

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, and 
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feed rate override
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.
 Commands like these should be self explanatory.
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The AXIS user interface removes some of the distinctions between Auto and
 the other modes by making Auto-commands available at most times.
 It also blurs the distinction between Manual and MDI because some Manual
 commands like Touch Off are actually implemented by sending MDI commands.
\the_end