Using This Help
---------------
This is a searchable text help file. To search for a keyword, type
Control-S or Control-R for a dialog box. Scroll bars work this way:
in a vertical scroll bar, right-click moves down, left click moves up,
and middle-click (or both, for two-button mice) grabs the scroll
point. In a horizontal scroll bar, right-click moves left (for some
reason known only to the X Windows folks), left-click moves right, and
middle-click grabs the scroll point.

Units
-----
The units for display of length values is determined by the INI
file. It is not affected by the units as selected in a program, and
you can't select other units. For example, if the INI file (usually
emc.ini) contains this entry in the TRAJ section:

     [TRAJ]
     LINEAR_UNITS =             inch

the units are inches.

(!) Note: we will probably add a menu item to select display
units, from either English, Metric, or Program. If Program units are
selected, the numbers will be displayed according to the G20/G21 modal
code in the program.

Top-Row Menus
-------------
File->Run... : prompts for an NC program to run. You need to be
in Auto mode, or you'll get an error.

File->Reset : resets the interpreter. The modal G and M codes are
set to their defaults.

File->Quit : quits the Xemc graphical application. The controller will
shutdown aswell.

View->Tools : shows the tool table. You can edit the table. Selecting
the Done button will save the table and reload it into the
controller. Note that Tab and Return affect the text, so you have to
click the Done button with the mouse.

View->Offsets and Variables : shows the interpreter parameters, which
hold the work offsets and user variables. You can edit the
file. Selecting the Done button will save the file and reload it into
the controller. Note that Tab and Return affect the text, so you have
to click the Done button with the mouse.

Settings->Relative Display, Actual Display : sets the display to show
positions as relative to the current work offset, or in absolute
machine coordinates. In relative display mode, the work offsets are
shown also.

Settings->Actual Position, Commanded Position : sets the display to
show either the actual position of the axes, as reported by their
feedback, or the commanded position, which is where the controller is
commanding them to go.

Help->Help... : brings up this help window.

Help->About... : brings up a credits window.

Status Command Buttons
----------------------
The buttons in the next two rows are labeled according to the current
EMC status. Click on them to pop up menus that send commands to the
EMC. The labels on these buttons will change to reflect the new
status.

ON/ESTOP-RESET/ESTOP : changes the power state of the machine. At
startup the machine is in ESTOP. Selecting Estop Reset will enable the
estop circuitry, but the servos will not yet be enabled. Selecting
Machine On will enable the servos. Selecting Machine Off will disable
the servos. Selecting Estop at any time will return the machine to the
initial estopped state. Function keys F1 and F2 will toggle the states
of the estop and servo systems, respectively. The Function Keys are
listed completely below.

(!) SAFETY NOTE: ESTOP will put the machine into the estopped state,
but should not be relied on for this action in the event of an
emergency. Always use the hardware estop to assure physical disabling
of the machine.

MANUAL/AUTO/MDI : changes the execution mode of the machine. Manual
mode allows the operator to jog and home the axes, and control the coolant
and spindle. Auto mode allows the operator to load programs into the
machine, run them, and pause/step/resume them. Manual Data Input (MDI)
mode allows the operator to type in blocks of NC code
interactively. Function key F3 puts the controller into manual
mode. F4 puts the controller into Auto mode. F5 puts the controller
into MDI mode.

MIST ON/OFF, FLOOD ON/OFF : turns mist or flood coolant on or
off. Function key F7 toggles the state of the mist coolant; F8 toggles
the flood coolant. These buttons and function keys only work in Manual
mode.

SPINDLE FORWARD/REVERSE/OFF : turns the spindle on forward, reverse,
or off. Function key F9 turns the spindle on forward if it's off, or
off if it's on. F10 turns the spindle on reverse if it's off, or off
it it's on. These buttons and function keys only work in Manual mode.

The speed of the spindle can be decreased or increased using the < and
> buttons to the left and right of the spindle control button,
respectively. F11 and F12, while pressed, decrease or increase the
spindle speed, respectively, until they are released. These buttons
and function keys work in manual, auto, or MDI mode. They are not
active when the spindle is off.

BRAKE ON/OFF : puts the spindle brake on, or releases it. This can be
used to manually operate the spindle brake for maintenance or tramming
operations. The 'B' and 'b' key, in manual mode,

ABORT : stops all motion and any program that is running. The Escape
key accomplishes the same result. Use ABORT or the Escape key to stop
machine motions while testing programs.

(!) NOTE: ABORT will not affect the estop state of the machine.

Tool and Tool Offset
--------------------
At the left, below the command buttons, is a display of the currently
loaded tool and the tool offset, if any. A value of 0 for the Tool
means that no tool is in the spindle. The offset is non-zero if a tool
length offset is active.

Position Display Options and Work Offsets
-----------------------------------------
At the right, below the command buttons, is a display showing how to
interpret the position numbers. There are two sources of position
feedback, either Commanded or Actual. Commanded numbers are what the
motion system asks for, and is not necessarily what the machine axes
positions are (servo lag may mean they are different). Actual numbers
reflect the current position of the axes. Normally, actual numbers are
what you want. In some cases, for example running a program in
simulation with the axes inhibited or disconnected, commanded numbers
are what you want.

Position numbers can also be Absolute or Relative. Absolute numbers
are not affected by any work offsets in a program. They are relative
to the machine home position. Relative numbers include any work
offset. If Relative numbers are selected, the applicable Work Offsets
are shown.

To change these settings, use the '@' key for Commanded/Actual, and
the '#' key for Absolute/Relative. The default values can be set in
the INI file, e.g.,

    [DISPLAY]
    POSITION_OFFSET =   RELATIVE
    POSITION_FEEDBACK = ACTUAL

or

    [DISPLAY]
    POSITION_OFFSET =   ABSOLUTE
    POSITION_FEEDBACK = COMMANDED

Axis Positions
--------------
Axis positions are displayed in a large font in the middle of the
display. The values are interpreted in units, commanded/actual, and
absolute/relative, as described above.

The color of the numbers shows the state of each axis. Yellow numbers
mean the axis has not yet been homed. Green numbers mean the axis has
been homed and is within limits. Red numbers mean the axis is at a
soft or hard limit.

Axis Command Buttons
--------------------
Below the axis position numbers is a row of command buttons that
affect axis motion. The Axis Speed setting, displayed in units/minute,
can be changed by clicking and holding the < or > buttons until the
desired setting is reached.

The Increment button shows the current
value of the jog increment, or "continuous" for continuous
jogging. Clicking on this button brings up a menu that changes the jog
increment or selects continuous jogging.

The Axis Motion buttons jog an axis in the negative direction using
the "-" button, positive direction using the "+" button, or home the
axis using the "home" button.

The Feed Override value in percent is displayed, and can be changed by
clicking and holding the < or > buttons until the desired setting is
reached.

Manual Data Input (MDI) Box
---------------------------
Below the axis command buttons is an input box labeled "MDI:" that is
active when the machine is in manual data input (MDI) mode. You can
type NC code statements into this box, and hit Enter to send the
command. Note that many of the function and alphanumeric accelerator
keys don't work as accelerator keys, so that they can be used to
compose MDI statements. Keys F1-F5 (estop state and manual/auto/mdi
mode), and F11-F12 (spindle speed control) do work; others do not.

Below the MDI box is a display of the current modal settings for G, M,
F, and S codes. These are only valid when in MDI mode. In Auto mode,
they hold the modal values up to the point where the interpreter has
read, usually far ahead of the executing line in the program. They do,
however, always show the modal groups that are applicable when you
next enter an MDI line.

Program Display
---------------
At the bottom of the main screen is a label showing the current
program, or the last program loaded. Below this is a row of command
buttons to Open, Run, Pause, Resume, or Step the program. The Open
button is identical to the File->Open... menu at the top, as is the
'o' or 'O' accelerator. The run, pause, resume, and step accelerators
are 'r', 'p', 's', and 'a', respectively, lower or upper case.

The window at the bottom shows a few lines of text of the currently
loaded program. The display window is moved through the program so
that the currently executing line is always at the top.

Function and Accelerator Keys
-----------------------------
Escape  abort motion                        <-|
F1      toggle estop/estop reset state        |
F2      toggle machine off/machine on state   |- work in MDI mode also
F3      manual mode                           |
F4      auto mode                             |
F5      MDI mode                            <-|
F6      reset interpreter
F7      toggle mist on/mist off
F8      toggle flood on/flood off
F9      toggle spindle forward/off
F10     toggle spindle reverse/off
F11     decrease spindle speed              <-|- work in MDI mode also
F12     increase spindle speed              <-|
x/X     select X axis
y/Y     select Y axis
z/Z     select Z axis
Left, Right Arrow  jog X axis
Up, Down Arrow     jog Y axis
Page Up, Down      jog Z axis
Home    home selected axis
<, >    decrement or increment axis speed
c/C     select continuous jogging
i/I     select incremental jog, and toggle through increments
1-9,0   set feed override to 10%-90%, 0 is 100%
@       toggle commanded/actual position display
#       toggle absolute/relative position display
o/O     open a program
r/R     run an opened program
p/P     pause an executing program
s/S     resume a paused program
a/A     step one line in a paused program
b       take spindle brake off
B       put spindle brake on
Alt-S   start logging
Alt-P   pause logging
Alt-F   save log file
Ctrl-P  print log file (if /usr/X11R6/bin/xgraph is installed)

Note that MDI mode disables most of the keys, since they are valid
symbols that can be typed in. F1-F5 work in MDI, as do the spindle
speed change keys F11 and F12.

The RS-274-NGC Interpreter
--------------------------
The EMC runs a dialect of RS-274 "G codes" that originated from
Allen-Bradley as part of their work for the National Center for
Manufacturing Sciences (NCMS) on the Next Generation Controller (NGC)
project. The dialect is similar to the Fanuc series of CNCs.

G codes:

G00 X Y Z          rapid feed
G01 X Y Z          linear feed, e.g., G01 X10 Y20 Z30 F60 for 60 ipm
G02 X Y Z I J      clockwise circular feed (helical with Z)
G03 X Y Z I J      counterclockwise circular feed (helical with Z)
G04 P<#>           dwell # of seconds
G10 L2 P<#> X Y Z  set coordinates for system #1-9, 1 = G54, 9 = G59.3
G17                XY plane circular interpolation
G18                ZX plane circular interpolation
G19                YZ plane circular interpolation
G20                English units (inches)
G21                metric units (millimeters)
G40                cancel cutter compensation
G41 D<#>           cutter compensation for tool <#>, tool on left
G42 D<#>           cutter compensation for tool <#>, tool on right
G43 H<#>           use tool length offset for tool #, 0 = no offset
G49                cancel tool length offset
G53                turn any coordinate offsets off for this block
G54                use coordinate offsets for system #1, from G10 L2 P1
G55                "" for system #2, from G10 L2 P2
G56                "" for system #3, from G10 L2 P3
G57                "" for system #4, from G10 L2 P4
G58                "" for system #5, from G10 L2 P5
G59                "" for system #6, from G10 L2 P6
G59.1              "" for system #7, G10 L2 P7
G59.2              "" for system #8, G10 L2 P8
G59.3              "" for system #9, G10 L2 P9
G61                exact stop mode
G64                cutting mode
G80                cancel fixed (canned) cycle
G81                drilling cycle, no dwell, rapid out
G82                drilling cycle, dwell, rapid out
G83                deep hole peck drilling cycle
G84                tapping cycle
G85                boring cycle, no dwell, feed out
G86                boring cycle, spindle stop, rapid out
G87                back boring cycle
G88                boring cycle, spindle stop, manual out
G89                boring cycle, with dwell, feed out
G90                non-incremental programming (the usual)
G91                incremental programming
G93                inverse time feed mode
G94                feed per minute mode (the usual)

M codes:

M0   optional program stop
M1   program stop
M2   program end
M3   turn spindle clockwise, e.g., S1000 M3 for 1000 rpm
M4   turn spindle counterclockwise
M5   turn spindle off
M6   tool change, e.g., T1 M6 for tool 1
M7   mist coolant on
M8   flood coolant on
M9   all coolant off
M48  disable feed override
M49  disable spindle speed override

Frequently Asked Questions (FAQ)
--------------------------------
Q. I get following errors on my stepper motor system. How can this be?
A. Because the commanded speed for an axis can be greater that the
fastest it can run, given the maximum pulse rate (something like 5
kilohertz). This means the axis can't keep up, so error builds up, and
you trip a following error. Change the INI file parameter for [TRAJ]
MAX_VELOCITY to be lower.

Q. The axes don't move when I try to jog them.
A. Make sure you're out of estop, in manual mode. If you still can't
jog then maybe the hard limit switches are seen as tripped. This often
happens when running the EMC without actual hardware, in which case
the bits float high. To correct this change the polarity of the limit
switches in your ini file (emc.ini, or whatever you are using), as in

[AXIS_0]
MIN_LIMIT_SWITCH_POLARITY =     1
MAX_LIMIT_SWITCH_POLARITY =     1

Change them and see if this clears the problem up.

Q. My script gives syntax errors when I run it, like this:

   'nknown option: `-
   Usage: csh [ -bcdefilmnqstvVxX ] [ argument ... ].

A. Make sure the name of the command interpreter is the first
characters of the first line of the script, e.g.,

-----top of file---
#!/bin/csh -f

Also, the file might be in DOS format. The 'vi' editor will show this
in the status line, e.g., when you type "vi emc.run", you'll get a
screen editor with this at the bottom:

"emc.run" [dos format] 3 lines, 25 characters

(Exit vi with :q). If it's DOS format, it needs to be converted back
to Unix format, which means the CR characters (decimal 13) need to be
LF characters (decimal 10). This can be easily done at the Unix prompt
using the 'tr' text replace program, e.g.,

      tr -d \\r < emc.run > new.run

which deletes all return characters, leaving the newlines alone, and
puts the result into new.run.

Q. Software limits don't work. I can jog past a soft limit.
A. Software limits only work when an axis has been homed, since
otherwise the machine doesn't know where the limits really are.

Q. Why doesn't the mouse or return key work?
A. Sometimes the cursor needs to be in the part of the window with the
text in it. Move the cursor to a different region and try it.

Q. Why aren't the modal G and M codes not correct in Auto mode?
A. The modes that will be active when you enter MDI mode are
shown. These are read ahead of actual program execution.

Q. Is there a Windows version of the EMC?
A. There is a version that runs in simulation. There are no reliable 
(and free) real-time extensions to Windows, which EMC can use.

Q. How can I change the fonts/colors/sizes in the Xemc display?
A. The "xemc" file in /etc/X11/app-defaults directory contains the X 
resources used by the program. Almost nothing is hard coded in the 
program itself. You can change any of these values and see the effects.
