Getting Started Guide V2.5

The minimum system to run EMC2 and Ubuntu may vary depending on the exact usage. Stepper systems in general require faster threads to generate step pulses than servo systems. Using the Live-CD you can test the software before committing a computer. Keep in mind that the Latency Test numbers are more important than the processor speed for software step generation. More information on the Latency Test is in Section ([sub:Latency-Test]).

Additional information is on the EMC Wiki site:

http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Hardware_Requirements

EMC2 and Ubuntu should run reasonably well on a computer with the following minimum hardware specification. These numbers are not the absolute minimum but will give reasonable performance for most stepper systems.

Laptops are not generally suited to real time software step generation. Again a Latency Test run for an extended time will give you the info you need to determine suitability.

If your installation pops up with 800 x 600 screen resolution then most likely Ubuntu does not recognize your video card or monitor. Onboard video many times causes bad real time performance.

Ubuntu has been chosen, because it fits perfectly into the Open Source views of EMC2:

IRC stands for Internet Relay Chat. It is a live connection to other EMC users. The EMC IRC channel is #emc on freenode.

The simplest way to get on the IRC is to use the embedded java client on this page http://www.linuxcnc.org/content/view/4/8/lang,en/.

Some IRC etiquette:

The most common way to share files on the IRC is to upload the file to one of the following or a similar service and paste the link:

An Internet Mailing List is a way to put questions out for everyone on that list to see and answer at their convenience. You get better exposure to your questions on a mailing list than on the IRC but answers take longer. In a nutshell you e-mail a message to the list and either get daily digests or individual replies back depending on how you set up your account.

Information about the EMC Users Mailing List at:

https://lists.sourceforge.net/lists/listinfo/emc-users

A Wiki site is a user maintained web site that anyone can add to or edit.

The user maintained EMC Wiki site contains a wealth of information and tips at:

http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl

Download the Live CD from:

http://www.linuxcnc.org/

and follow the Download link.

If the file is too large to download in one session because of a resuming downloads.

Open a terminal window. In Ubuntu it is Applications/Accessories/Terminal. Note that actual file names may change so you might have to go to http://www.linuxcnc.org/ and follow the Download link to get the actual file name. In most browsers you can right click on the link and select Copy Link Location or similar then paste the link into the terminal window with a right mouse click and select Paste.

To get the Ubuntu 8.04 Hardy Heron version copy this in the terminal window and press enter:

{textbf{wget -r http://www.linuxcnc.org/hardy/ubuntu-8.04-desktop-emc2-aj07-i386.iso}To} get the Ubuntu 6.06 Dapper Drake version:

{textbf{wget -r http://www.linuxcnc.org/iso/emc2.2.2-1-ubuntu6.06-desktop-i386.iso}To} continue a download that has been stopped add the -c option to wget:

{textbf{wget -r -c http://www.linuxcnc.org/hardy/ubuntu-8.04-desktop-emc2-aj07-i386.iso}To} stop a download use Ctrl-C or close the terminal window.

After the download is complete you will find a new directory called www.linuxcnc.org or something similar. In the subdirectory under the above directory you will find the ISO CD image file. Next is burning the CD.

The wget program is also available for Windows from

http://gnuwin32.sourceforge.net/packages/wget.htm

Follow the instructions on the web page for downloading and installing the windows version of the wget program.

To run wget open a command prompt window.

In most Windows it is Programs/Accessories/Command Prompt

First you have to change to the directory where wget is installed in.

Typically it is in C:\\Program Files\\GnuWin32\\bin so in the Command Prompt window type:

{textbf{cd C:\\textbackslashProgram Files\\textbackslashGnuWin32\\textbackslashbin}}and the prompt should change to C:\\Program Files\\GnuWin32>

Type the wget command into the window and press enter as above.

EMC2 is distributed as CD image files, called ISOs. To install EMC2, you first need to burn the ISO file onto a CD. You need a working CD/DVD burner and an 80 minute (700 Mb) CD for this. If the CD writing fails, try writing at a slower burn speed.

Before burning a CD, it is highly recommended that you verify the md5 sum (hash) of the .iso file.

Open a terminal window. In Ubuntu it is Applications/Accessories/Terminal.

Change to the directory where the ISO was downloaded to.

{textbf{cd download\\\_directory}}The run the md5sum command with the file name you saved.

{textbf{md5sum ubuntu-8.04-desktop-emc2-aj07-i386.iso}}The md5sum should print out a single line after calculating the hash. On slower computers this might take a minute or two.

{textbf{91c5abb84386091e0ff056e9ebc40fdb ubuntu-8.04-desktop-emc2-aj07-i386.iso}}Now compare it to the md5sum on the EMC2 download page.

Burning the ISO to a CD

Before burning a CD, it is highly recommended that you verify the md5 sum (hash) of the .iso file.

Windows does not come with a md5sum program. You will have to download and install one to check the md5sum. More information can be found at:

https://help.ubuntu.com/community/HowToMD5SUM

Burning the ISO to a CD

With the Live CD in the CD/DVD drive shut down the computer then turn the computer back on. This will boot the computer from the Live CD. Once the computer has booted up you can try out EMC2 without installing it. You can not create custom configurations or modify most system settings like screen resolution unless you install EMC2.

To try out EMC2 from the Applications/CNC menu pick EMC2. Then select a sim configuration to try out.

To see if your computer is suitable for software step pulse generation run the Latency Test as outlined in Section ([sub:Latency-Test])

If you like what you see, just click the Install icon on the desktop, answer a few questions (your name, timezone, password) and the install completes in a few minutes. Make sure you write down the name you used and the password. Once the install process is complete and you go on line the update manager will pop up and allow you to upgrade to the latest stable version of EMC2.

The AXIS interface is one of the interfaces to choose from. It can be configured to add a Virtual Control Panel to customize the interface to suit your needs. AXIS is the default user interface and is actively being developed.

.

With the normal install the Update Manager will notify you of updates to EMC2 when you go on line and allow you to easily upgrade with no Linux knowledge needed. If you want to upgrade to 10.04 from 8.04 a clean install from the Live-CD is needed. It is OK to upgrade EMC when asked to.

Warning: Do not upgrade Ubuntu to a new version (like 8.04 to 8.10) as it will prevent EMC from running.

In rare cases you might have to reset the BIOS to default settings if during the Live CD install it can not recognize the hard drive during the boot up.

The following instructions only apply to Ubuntu 8.04 Hardy Heron. EMC 2.4 is not available for older releases of Ubuntu.

Because there are several minor incompatibilities between 2.3.5 and 2.4.x, your existing install will not automatically be updated to 2.4.x. If you want to run 2.4.x, change to the EMC-2.4 repository by following these instructions:

run System/Administration/Synaptic Package Manager

go to Settings/Repositories

In the list of Third-Party software there should be at least two lines for linuxcnc.org.

For each of them:

Close the Software Preferenceswindow

Click Reloadas instructed

Click Mark All UpgradesIf you use a mesa card, find the proper hostmot2-firmware package for your card and mark it for installation. Hint: do a search for hostmot2-firmware in the synaptic package manager.

Click Apply

Once you have done the upgrade, update any custom configurations by following these instructions:

For configurations that have not customized emc.nml, remove the inifile line NML\_FILE = emc.nml. This will cause the most up to date version of emc.nml to be used.

For configurations that have customized emc.nml, a change similar to this one is required.

Failure to do this can cause an error like libnml/buffer/physmem.cc 143: PHYSMEM\_HANDLE: Can’t write 10748 bytes at offset 60 from buffer of size 10208.{tool table changes }The format of the tool table has been changed incompatibly. The documentation shows the new format. The tool table will automatically be converted to the new format.

The hostmot2 firmware images are now a separate package. You can:

This section assumes you have done a standard install from the Live CD. After installation it is recommended that you connect the computer to the Internet and wait for the update manager to pop up and get the latest updates for EMC and Ubuntu before continuing. For more complex installations see the Integrators Manual.

The Latency Test determines how late your computer processor is in responding to a request. Some hardware can interrupt the processing which could cause missed steps when running a CNC machine. This is the first thing you need to do. Follow the instructions in section ([sub:Latency-Test]) to run the latency test.

If you have a Sherline several predefined configurations are provided. This is on the main menu CNC/EMC then pick the Sherline configuration that matches yours and save a copy.

If you have a Xylotex you can skip the following sections and go straight to the Stepper Config Wizard in Section ([cha:Stepconf-Wizard]). EMC has provided quick setup for the Xylotex machines.

Gather the information about each axis of your machine.

Drive timing is in nano seconds. If your unsure about the timing many popular drives are included in the stepper configuration wizard. Note some newer Gecko drives have different timing than the original one. A list is also on the user maintained EMC wiki site of more drives at http://wiki.linuxcnc.org.

Gather the information about the connections from your machine to the PC parallel port.

Note any pins not used should be set to Unused in the drop down box. These can always be changed later by running Stepconf again.

Gather information on steps and gearing. The result of this is steps per user unit which is used for SCALE in the .ini file.

Steps per revolution is how many steps it takes to turn the stepper one revolution.

Micro steps is how many steps the drive needs to move the stepper one step.

Motor & Leadscrew Teeth is if you have some reduction between the motor and the leadscrew. If not set these to 1.

Leadscrew pitch is how many turns it takes to move your table one user unit. If your setting up in inches then it is turns per inch. If your setting up in millimeters then how many turns per millimeter.

Run the Stepconf Wizard in chapter ([cha:Stepconf-Wizard])

To change something in the basic configuration created by Stepconf Wizard run the wizard again. Select Modify a configuration… Then pick the configuration file .stepconf you wish to modify in the emc2/configs folder. The file headers tell you if the file can be manually edited or not.

EMC2 is capable of controlling a wide range of machinery using many different hardware interfaces. Stepconf is a program which generates EMC configuration files for a specific class of CNC machine: those connected to the PC using a standard parallel port and controlled with step & direction signals. Stepconf is installed when you install EMC2 and is in the CNC menu.

Stepconf places a file in the emc2/config directory to store the choices for each configuration you create. When you change something you need to pick the file that matches your configuration name. The file extension is .stepconf.

The Stepconf Wizard needs at least 800 x 600 screen resolution to see the buttons on the bottom of the pages.

While the test is running, you should abusethe computer. Move windows around on the screen. Surf the web. Copy some large files around on the disk. Play some music. Run an OpenGL program such as glxgears. The idea is to put the PC through its paces while the latency test checks to see what the worst case numbers are. Do not run EMC2 while the latency test is running. Run the test at least a few minutes. The longer you run the test the better it will be at catching events that might occour at less frequent intervals. This is a test for your computer only, so no hardware needs to be connected to run the test.

Latency is how long it takes the PC to stop what it is doing and respond to an external request. In our case, the request is the periodic heartbeatthat serves as a timing reference for the step pulses. The lower the latency, the faster you can run the heartbeat, and the faster and smoother the step pulses will be.

Latency is far more important than CPU speed. The CPU isn’t the only factor in determining latency. Motherboards, video cards, USB ports, SMI nuxcnc.org/cgi-bin/emcinfo.pl?FixingSMIIssues issues, and a number of other things can hurt the latency.

The important numbers are the max jitter. In the example above 7085 nanoseconds is the highest jitter. Record this number, and enter it in the Base Period Maximum Jitter box.

If your Max Jitter number is less than about 15-20 microseconds (15000-20000 nanoseconds), the computer should give very nice results with software stepping. If the max latency is more like 30-50 microseconds, you can still get good results, but your maximum step rate might be a little disappointing, especially if you use microstepping or have very fine pitch leadscrews. If the numbers are 100uS or more (100,000 nanoseconds), then the PC is not a good candidate for software stepping. Numbers over 1 millisecond (1,000,000 nanoseconds) mean the PC is not a good candidate for EMC, regardless of whether you use software stepping or not.

For each pin, choose the signal which matches your parallel port pin out. Turn on the invertcheck box if the signal is inverted (0V for true/active, 5V for false/inactive).

With Stepconf it is easy to try different values for acceleration and velocity.

Begin with a low Acceleration (e.g., 2 in/s2 or 50mm/s2) and the velocity you hope to attain. Using the buttons provided, jog the axis to near the center of travel. Take care because with a low acceleration value, it can take a surprising distance for the axis to decelerate to a stop.

After gauging the amount of travel available, enter a safe distance in Test Area, keeping in mind that after a stall the motor may next start to move in an unexpected direction. Then click Run. The machine will begin to move back and forth along this axis. In this test, it is important that the combination of Acceleration and Test Area allow the machine to reach the selected Velocity and cruisefor at least a short distance-the more distance, the better this test is. The formula d=.5{*}v{*}v/a gives the minimum distance required reach the specified velocity with the given acceleration. If it is convenient and safe to do so, push the table against the direction of motion to simulate cutting forces. If the machine stalls, reduce the speed and start the test again.

If the machine did not obviously stall, click the Runbutton off. The axis now returns to the position where it started. If the position is incorrect, then the axis stalled or lost steps during the test. Reduce Velocity and start the test again.

If the machine doesn’t move, stalls, or loses steps no matter how low you turn Velocity, verify the following:

Once you have found a speed at which the axis does not stall or lose steps during this testing procedure, reduce it by 10% and use that as the axis Maximum Velocity.

With the Maximum Velocity you found in the previous step, enter the acceleration value to test. procedure as above, adjusting the Acceleration value up or down as necessary. In this test, it is important that the combination of Acceleration and Test Area allow the machine to reach the selected Velocity. Once you have found a value at which the axis does not stall or lose steps during this testing procedure, reduce it by 10% and use that as the axis Maximum Acceleration.

This page only appear when Spindle PWMis chosen in the Parallel Port Pinout page for one of the outputs.

If Spindle PWMappears on the pinout, the following information should be entered:

When the appropriate signals from a spindle encoder are connected to the parallel port, EMC supports lathe threading. These signals are:

If Spindle Phase Aand Spindle Indexappear on the pinout, the following information should be entered:

Enter the following values in the Spindle Configuration page:

Finish the remaining steps of the configuration process, then launch EMC with your configuration. Turn the machine on and select the MDI tab. Start the spindle turning by entering: `M3 S100. Change the spindle speed by entering a different S-number: ``S800`. Valid numbers range from 1 to 1000.

For two different S-numbers, measure the actual spindle speed in RPM. Record the S-numbers and actual spindle speeds. Run Stepconf again. For Speedenter the measured speed, and for PWMenter the S-number divided by 1000.

Because most spindle drivers are somewhat nonlinear in their response curves, it is best to:

For instance, if your spindle will go from 0RPM to 8000RPM, but you generally use speeds from 400RPM to 4000RPM, then find the PWM values that give 1600RPM and 2800RPM.

Click "Apply" to write the configuration files. Later, you can re-run this program and tweak the settings you entered before.

For each axis, there is a limited range of travel. The physical end of travel is called the hard stop.

Before the hard stop there is a limit switch. If the limit switch is encountered during normal operation, EMC shuts down the motor amplifier. The distance between the hard stop and limit switch must be long enough to allow an unpowered motor to coast to a stop.

Before the limit switch there is a soft limit. This is a limit enforced in software after homing. If a MDI command, or g code program would pass the soft limit, it is not executed. If a jog would pass the soft limit, it is terminated at the soft limit.

The home switch can be placed anywhere within the travel (between hard stops). As long as external hardware does not deactivate the motor amplifiers with the limit switch is reached, one of the limit switches can be used as a home switch.

The zero position is the location on the axis that is 0 in the machine coordinate system. Usually the zero position will be within the soft limits. On lathes, constant surface speed mode requires that machine X=0 correspond to the center of spindle rotation when no tool offset is in effect.

The home position is the location within travel that the axis will be moved to at the end of the homing sequence. This value must be within the soft limits. In particular, the home position should never be exactly equal to a soft limit.

A machine can be operated without limit switches. In this case, only the soft limits stop the machine from reaching the hard stop. Soft limits only operate after the machine has been homed.

A machine can be operated without home switches. If the machine has limit switches, but no home switches, it is best to use a limit switch as the home switch (e.g., choose Minimum Limit + Home X in the pinout). If the machine has no switches at all, or the limit switches cannot be used as home switches for another reason, then the machine must be homed by eyeor by using match marks. Homing by eye is not as repeatable as homing to switches, but it still allows the soft limits to be useful.

The ideal wiring for external switches would be one input per switch. However, the PC parallel port only offers a total of 5 inputs, while there are as many as 9 switches on a 3-axis machine. Instead, multiple switches are wired together in various ways so that a smaller number of inputs are required.

The figures below show the general idea of wiring multiple switches to a single input pin. In each case, when one switch is actuated, the value seen on INPUT goes from logic HIGH to LOW. However, EMC expects a TRUE value when a switch is closed, so the corresponding Invertbox must be checked on the pinout configuration page.

The following combinations of switches are permitted in Stepconf:

The last two combinations are also appropriate when a home to limitis used.

The Point n Click Configurator covers Mesa cards and parallel port stepper configurations. If you have a simple parallel port stepper machine the StepConf Wizard might be a better choice. The Point n Click Configurator can generate some advanced configurations without knowing anything about HAL.

Start the PnCConf program from the CNC menu or from a terminal window with `pncconf`. For more information on the terminal window see the Linux FAQ section.

Here you can select from different GUI’s and options for each one.

Axis Drive Configuration

Axis Configuration

On this page you can add additional HAL components you might need.

After installation, EMC2 starts just like any other piece of Linux software: run it from the terminal by issuing the command `emc`, or select it in the Applications > CNC menu.

By default, the Configuration Selector dialog is shown when you first run EMC. Your own personalized configurations are shown at the top of the list, followed by sample configurations. Since each sample configuration is for a different type of hardware interface, some will not run without the hardware installed. The configurations listed under the category simrun entirely without attached hardware.

\\label{cap:EMC2-Configuration-SelectorEMC2 Configuration Selector}

Click any of the listed configurations to display specific information about it. Double-click a configuration or click OK to start the configuration. Select Create Desktop Shortcutand then click OK to add an icon on the Ubuntu desktop to directly launch this configuration without showing the Configuration Selector screen.

If you select a configuration from the Sample Configurations section, you will be asked to copy the configuration to a location in your home directory. It is safe to say yesto this prompt. If you say no, EMC may start but will behave strangely-for instance, offsets entered with Touch Off will be cleared unexpectedly. This is because the files are read only if you don’t save a copy to your home directory.

Copy Configuration Dialog

After finding the sample configuration that uses the same interface hardware as your machine, and saving a copy to your home directory you can customize it according to the details of your machine. Refer to the Integrators Manual for topics on configuration.

These are some basic Linux commands and techniques for new to Linux users. More complete information can be found on the web or by using the man pages.

When you install EMC2 with the Ubuntu LiveCD the default is to have to log in each time you turn the computer on. To enable automatic login go to System/Administration/Login Window. If it is a fresh install the Login Window might take a second or three to pop up. You will have to have your password that you used for the install to gain access to the Login Window Preferences window. In the Security tab check off Enable Automatic Login and pick a user name from the list (that would be you).

To have EMC start automatically with your config after turning on the computer go to System/Preferences/Sessions Startup Programs , add new. Navigate to your config and select the .ini file. When the file picker dialog closes add emc and a space in front of the path to your .ini file.

Example:

Man pages are automatically generated manual pages in most cases. Man pages are usually available for most programs and commands in Linux.

To view a man page open up a terminal window by going to Applications, Accessories, Terminal. For example if you wanted to find out something about the find command in the terminal window type:

Use the Page Up and Page Down keys to view the man page and the Q key to quit viewing.

Sometimes when troubleshooting you need to get a list of modules that are loaded. In a terminal window type:

If you want to send the output from lsmod to a text file in a terminal window type:

The resulting text file will be located in the home directory if you did not change directories when you opened up the terminal window and it will be named mymod.txt or what ever you named it.

When you open the file browser and you see the Owner of the file is root you must do extra steps to edit that file. Editing some root files can have bad results. Be careful when editing root files. You can open and view most root files normally but they will open in "read only" mode.

Open up Applications, Accessories, Terminal.

In the terminal window type

Open the file with File, Open then edit

In Ubuntu you can become root by typing in sudo -iin a terminal window then typing in your password. You can really foul up things if you don’t know what your doing as root.

To find out the path to the present working directory in the terminal window type:

To move up one level in the terminal window type:

To move up two levels in the terminal window type:

To move down to the emc2/configs subdirectory in the terminal window type:

To view a list of all the files and subdirectories in the terminal window type:

or

The find command can be a bit confusing to a new Linux user. The basic syntax is:

For example to find all the .ini files in your emc2 directory you first need to use the pwd command to find out the directory. Open a new terminal window and type:

might return the following result

With this information put the command together like this:

The -name is the name of the file your looking for and the -print tells it to print out the result to the terminal window. The {*}.ini tells find to return all files that have the .ini extension.

To find all the files in the directory named and all the subdirectories under that add the -L option to the find command like this:

To find all the files that contain the text to search for in the current directory and all the subdirectories below the current while ignoring the case. The -i is for ignore case and the -r is for recursive (include all subdirectories in the search). The {*} is a wild card for search all files.

To view the bootup messages use dmesgfrom the command window. To save the bootup messages to a file use the redirection operator like this:

The contents of this file can be copied and pasted on line to share with people trying to help you diagnose your problem.

To clear the message buffer type this:

This can be useful to do just before you launch EMC to only show the infomation related to the start up of EMC.

If you want to add a terminal launcher to the panel bar on top of the screen you typically can right click on the panel at the top of the screen and select Add to Panel. Select Custom Application Launcher and Add. Give it a name and put gnome-terminal in the command box.

To find out what hardware is connected to your motherboard in a terminal window type:

During installation Ubuntu attempts to detect the monitor settings. If this fails you are left with a generic monitor with a maximum resolution of 800x600.

Instructions for fixing this are located here:

https://help.ubuntu.com/community/FixVideoResolutionHowto

Copyright (c) 2000 LinuxCNC.org

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and one Back-Cover Text: This EMC Handbook is the product of several authors writing for linuxCNC.org. As you find it to be of value in your work, we invite you to contribute to its revision and growth.A copy of the license is included in the section entitled GNU Free Documentation License. If you do not find the license you may order a copy from Free Software Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307

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The End