Commit Graph

91 Commits

Author SHA1 Message Date
Sonny Jeon
08baabc63c Minor updates to code and commenting. 2013-03-28 10:11:41 -06:00
Sonny Jeon
3c9c516a47 Untested! Soft limits, max travel, homing changes, new settings.
- WARNING: Completely untested. Will later when there is time. Settings
WILL be overwritten, as there are new settings.

- Soft limits installed. Homing must be enabled for soft limits to work
correctly. Errors out much like a hard limit, locking out everything
and bringing up the alarm mode. Only difference is it forces a feed
hold before doing so. Position is not lost.

- IMPORTANT: Homing had to be updated so that soft limits work better
with less CPU overhead. When homing completes, all axes are assumed to
exist in negative space. If your limit switch is other side, the homing
cycle with set this axis location to the max travel value, rather than
zero.

- Update mc_line() to accept an array, rather than individual variables.

- Added an mc_auto_cycle_start() function handle this feature.
Organization only.

-
2013-03-21 19:22:07 -06:00
Sonny Jeon
97d18f0ffe Merge bug fixes from recent v0.8c push. Added readme for Grbl Sim. 2013-01-18 17:02:44 -07:00
Sonny Jeon
5e7c25d480 Updated README. Max step rate back at 30kHz. Acceleration minor bug fix.
- Returned the max step rate to 30kHz. The new arc algorithm works uses
so much less CPU overhead, because the segments are longer, that the
planner has no problem computing through them.

- Fixed an issue with the acceleration independence scaling. Should now
work with accelerations above 400mm/sec^2 or so.

- Updated README
2012-12-21 08:51:36 -07:00
Sonny Jeon
3dfffa622d Arc mm_per_segment removed, now in terms of tolerance. Stepper ramp counter variable type corrected.
- Arc mm_per_segment parameter was removed and replaced with an
arc_tolerance parameter, which scales all arc segments automatically to
radius, such that the line segment error doesn't exceed the tolerance.
Significantly improves arc performance through larger radius arc,
because the segments are much longer and the planner buffer has more to
work with.

- Moved n_arc correction from the settings to config.h. Mathematically
this doesn't need to be a setting anymore, as the default config value
will work for all known CNC applications. The error does not accumulate
as much anymore, since the small angle approximation used by the arc
generation has been updated to a third-order approximation and how the
line segment length scale with radius and tolerance now. Left in
config.h for extraneous circumstances.

- Corrected the st.ramp_count variable (acceleration tick counter) to a
8-bit vs. 32-bit variable. Should make the stepper algorithm just a
touch faster overall.
2012-12-19 17:30:09 -07:00
Sonny Jeon
a1397f61c4 Max velocity axes independence installed. Fixed intermittent slow trailing steps. Timer0 disable fix.
- Maximum velocity for each axis is now configurable in settings. All
rapids/seek move at these maximums. All feed rates(including rapids)
may be limited and scaled down so that no axis does not exceed their
limits.

- Moved around auto-cycle start. May change later, but mainly to ensure
the planner buffer is completely full before cycle starting a streaming
program. Otherwise it should auto-start when there is a break in the
serial stream.

- Reverted old block->max_entry_speed_sqr calculations. Feedrate
overrides not close to ready at all.

- Fixed intermittent slow trailing steps for some triangle velocity
profile moves. The acceleration tick counter updating was corrected to
be exact for that particular transition. Should be ok for normal
trapezoidal profiles.

- Fixed the Timer0 disable after a step pulse falling edge. Thanks
@blinkenlight!
2012-12-16 16:23:24 -07:00
Sonny Jeon
bba633101a G28/G30 post move bug fix. Altered file permissions. 2012-11-25 22:02:33 -07:00
Sonny Jeon
d85238cc9b Homing search sequence now compile-time option. New defaults.h file. Tidying up.
- The homing sequence is now a compile-time option, where a user can
choose which axes(s) move in sequence during the search phase. Up to 3
sequences. Works with the locating phase and the pull-off maneuver.

- New defaults.h file to store user generated default settings for
different machines. Mainly to be used as a central repo, but each set
may be select to be compiled in as a config.h define.
2012-11-18 19:52:16 -07:00
Sonny Jeon
5dd6d90122 Added Grbl state in status report. Removed switch support.
- Added Grbl state (Idle, Running, Queued, Hold, etc) to the real-time
status reporting feature as feedback to the user of what Grbl is doing.
Updated the help message to reflect this change.

- Removed switches (dry run, block delete, single block mode). To keep
Grbl simple and not muddled up from things that can easily be taken
care of by an external interface, these were removed.

- Check g-code mode was retained, but the command was moved to '$C'
from '$S0'.
2012-11-15 21:53:11 -07:00
Sonny Jeon
559feb97e2 Re-factored system states and alarm management. Serial baud support greater than 57600.
- Refactored system states to be more clear and concise. Alarm locks
processes when position is unknown to indicate to user something has
gone wrong.

- Changed mc_alarm to mc_reset, which now manages the system reset
function. Centralizes it.

- Renamed '$X' kill homing lock to kill alarm lock.

- Created an alarm error reporting method to clear up what is an alarm:
message vs a status error: message. For GUIs mainly. Alarm codes are
negative. Status codes are positive.

- Serial baud support upto 115200. Previous baudrate calc was unstable
for 57600 and above.

- Alarm state locks out all g-code blocks, including startup scripts,
but allows user to access settings and internal commands. For example,
to disable hard limits, if they are problematic.

- Hard limits do not respond in an alarm state.

- Fixed a problem with the hard limit interrupt during the homing
cycle. The interrupt register is still active during the homing cycle
and still signal the interrupt to trigger when re-enabled. Instead,
just disabled the register.

- Homing rate adjusted. All axes move at homing seek rate, regardless
of how many axes move at the same time. This is unlike how the stepper
module does it as a point to point rate.

- New config.h settings to disable the homing rate adjustment and the
force homing upon powerup.

- Reduced the number of startup lines back down to 2 from 3. This
discourages users from placing motion block in there, which can be very
dangerous.

- Startup blocks now run only after an alarm-free reset or after a
homing cycle. Does not run when $X kill is called. For satefy reasons
2012-11-14 17:36:29 -07:00
Sonny Jeon
e6ad15b548 Tweaks. Seek rate updates when set. CCW arc full circle fix.
- Fixed a minor issue where the seek rates would not immediately be
used and only would after a reset. Should update live now.

- A full circle IJ offset CCW arc would not do anything. Fixed bug via
a simple if-then statement.

- Radius mode tweaks to check for negative value in sqrt() rather than
isnan() it. Error report updated to indicate what actually happened.
2012-11-10 12:49:33 -07:00
Sonny Jeon
978de77c2f Added note that D13 can't be used as input, pulled-high. 2012-11-09 18:33:38 -07:00
Sonny Jeon
5844172af1 Fixed homing cycle hanging after locating switches. 2012-11-09 16:25:42 -07:00
Sonny Jeon
f41dd69273 Tweaks and bug fixes. Increase to 3 startup blocks. Remove purge/added unlock command
- Increased the number of startup blocks to 3 for no good reason other
than it doesn't increase the flash size.

- Removed the purge buffer command and replaced with an disable homing
lock command.

- Homing now blocks all g-code commands (not system commands) until the
homing cycle has been performed or the disable homing lock is sent.
Homing is required upon startup or if Grbl loses it position. This is
for safety reasons.

- Cleaned up some of the Grbl states and re-organized it to be little
more cohesive.

- Cleaned up the feedback and status messages to not use so much flash
space, as it's a premium now.

 - Check g-code and dry run switches how are mutually exclusive and
can't be enabled when the other is. And automatically resets Grbl when
disabled.

- Some bug fixes and other minor tweaks.
2012-11-05 21:40:52 -07:00
Sonny Jeon
8c0106c247 Tweaks and minor bug fixes. Added purge buffer command.
- Added a purge buffer (and lock) command. This is an advanced option
to clear any queued blocks in the buffer in the event of system
position being lost or homed. These queued blocks will likely not move
correctly if not purged. In typical use, the purging command releases
the homing axes lock in case a user need to move the axes off their
hard limit switches, but position is not guaranteed. Homing is advised
immediately after.

- Created a system-wide sync current position function. Cleans up some
of the repetitive tasks in various places in the code that do the same
thing.

- Removed the clear all switches command '$S'. Not really needed and
helped clean up a sync call.

- Other minor tweaks. Readme updated slightly..
2012-11-04 08:44:54 -07:00
Sonny Jeon
4c711a4af7 New startup script setting. New dry run, check gcode switches. New system state variable. Lots of reorganizing.
(All v0.8 features installed. Still likely buggy, but now thourough
testing will need to start to squash them all. As soon as we're done,
this will be pushed to master and v0.9 development will be started.
Please report ANY issues to us so we can get this rolled out ASAP.)

- User startup script! A user can now save one (up to 5 as compile-time
option) block of g-code in EEPROM memory. This will be run everytime
Grbl resets. Mainly to be used as a way to set your preferences, like
G21, G54, etc.

- New dry run and check g-code switches. Dry run moves ALL motions at
rapids rate ignoring spindle, coolant, and dwell commands. For rapid
physical proofing of your code. The check g-code switch ignores all
motion and provides the user a way to check if there are any errors in
their program that Grbl may not like.

- Program restart! (sort of). Program restart is typically an advanced
feature that allows users to restart a program mid-stream. The check
g-code switch can perform this feature by enabling the switch at the
start of the program, and disabling it at the desired point with some
minimal changes.

- New system state variable. This state variable tracks all of the
different state processes that Grbl performs, i.e. cycle start, feed
hold, homing, etc. This is mainly for making managing of these task
easier and more clear.

- Position lost state variable. Only when homing is enabled, Grbl will
refuse to move until homing is completed and position is known. This is
mainly for safety. Otherwise, it will let users fend for themselves.

- Moved the default settings defines into config.h. The plan is to
eventually create a set of config.h's for particular as-built machines
to help users from doing it themselves.

- Moved around misc defines into .h files. And lots of other little
things.
2012-11-03 11:32:23 -06:00
Sonny Jeon
e0a9054e32 New report module. 6 persistent work coordinates. New G-codes and settings. README and minor bug updates
(NOTE: This push is likely buggy so proceed with caution. Just
uploading to let people know where we're going.)

- New report.c module. Moved all feedback functions into this module to
centralize these processes. Includes realtime status reports, status
messages, feedback messages.

- Official support 6 work coordinate systems (G54-G59), which are
persistently held in EEPROM memory.

- New g-code support: G28.1, G30.1 stores current machine position as a
home position into EEPROM. G10 L20 Px stores current machine position
into work coordinates without needing to explicitly send XYZ words.

- Homing performed with '$H' command. G28/G30 no longer start the
homing cycle. This is how it's supposed to be.

- New settings: Stepper enable invert and n_arc correction installed.

- Updated and changed up some limits and homing functionality. Pull-off
travel will now move after the homing cycle regardless of hard limits
enabled. Fixed direction of pull-off travel (went wrong way).

- Started on designing an internal Grbl command protocol based on the
'$' settings letter. Commands with non numeric characters after '$'
will perform switch commands, homing cycle, jogging, printing
paramters, etc. Much more to do here.

- Updated README to reflect all of the new features.
2012-11-01 09:37:27 -06:00
Sonny Jeon
065ceceb34 New alarm method. Re(re)organized status messages.
- Installed a new 'alarm' method to centralize motion kills across
alarm or reset events. Right now, this is controlled by system abort
and hard limits. But, in the future, a g-code parser error may call
this too as a safety feature.

- Re(re)organized status messages to just print all errors, regardless
from where it was called. This centralizes them into one place.

- Misc messages method installed for any user feedback that is not a
confirmation or error. Mainly so that there is a place to perform
warnings and such.

- New stuff installed and still made the flash size smaller by saving
flash space from clearing out repeated '\r\n' pgmstrings.

- Fixed a bug where hard limits message would print everytime a system
abort was sent.
2012-10-21 19:18:24 -06:00
Sonny Jeon
39e11b696f Hard limits code minor updates.
- Fixed a bug that would not disable the steppers if a user issues a
system abort during a homing cycle.

- Updated the hard limit interrupt to be more correct and to issue a
shutdown for the right situations when the switch has been triggered.

- Added a status message to indicate to the user what happened and what
to do upon a hard limit trigger.
2012-10-18 21:29:07 -06:00
Sonny Jeon
df5bb70b25 Hard limits, homing direction, pull-off limits after homing, status reports in mm or inches, system alarm, and more.
- Thank you statement added for Alden Hart of Synthetos.

- Hard limits option added, which also works with homing by pulling off
the switches to help prevent unintended triggering. Hard limits use a
interrupt to sense a falling edge pin change and immediately go into
alarm mode, which stops everything and forces the user to issue a reset
(Ctrl-x) or reboot.

- Auto cycle start now a configuration option.

- Alarm mode: A new method to kill all Grbl processes in the event of
something catastrophic or potentially catastropic. Just works with hard
limits for now, but will be expanded to include g-code errors (most
likely) and other events.

- Updated status reports to be configurable in inches or mm mode. Much
more to do here, but this is the first step.

- New settings: auto cycle start, hard limit enable, homing direction
mask (which works the same as the stepper mask), homing pulloff
distance (or distance traveled from homed machine zero to prevent
accidental limit trip).

- Minor memory liberation and calculation speed ups.
2012-10-16 21:29:45 -06:00
Sonny Jeon
ff82489da7 Limit pin internal pull-resistors enabled. Re-wrote read_double() function. Correctly changed all 'double's to 'float's.
- Limit pin internal pull-resistors now enabled. Normal high operation.
This will be the standard going forward.

- Updated all of the 'double' variable types to 'float' to reflect what
happens when compiled for the Arduino. Also done for compatibility
reasons to @jgeisler0303 's Grbl simulator code.

- G-code parser will now ignore 'E' exponent values, since they are
reserved g-code characters for some machines. Thanks @csdexter!

- The read_double() function was re-written and optimized for use in
Grbl. The strtod() avr lib was removed.
2012-10-08 15:57:58 -06:00
Sonny Jeon
d30cb906f8 Updated limit/homing routine. Works, but needs more TLC.
- Added acceleration to the homing routine.

- Homing now accounts for different step rates when moving multiple
axes without exceeding acceleration limits.

- Homing now updates all internal positioning variables to machine zero
after completion.

- "Poor-man's" debounce delay added.

- Updated the delay_us() function to perform faster and more accurate
microsecond delays. Previously, the single increments would add
noticeable time drift for larger delays.

- Fix a bug in the stepper.c prescalar calculations that was changed in
the last commit.

- Other minor fixes.
2012-09-30 19:57:10 -06:00
Sonny Jeon
1720484d76 No changes. Github commit bug. 2012-06-27 07:06:24 -06:00
Sonny Jeon
b51e902530 Program stop support (M0,M1*,M2,M30*), proper position retainment upon reset, misc minor updates.
- Program stop support (M0,M1*,M2,M30*). *Optional stop to be done.
*Pallet shuttle not supported.

- Work position is set equal to machine position upon reset, as
according to NIST RS274-NGC guidelines. G92 is disabled.

- Renamed mc_set_current_position() to mc_set_coordinate_offset().

- Fixed bug in plan_synchronize(). Would exit right before last step is
finished and caused issues with program stops. Now fixed.

- Spindle now stops upon a run-time abort command.

- Updated readme and misc upkeeping.
2012-01-28 20:41:08 -07:00
Sonny Jeon
d27dd13a54 Fix bug with premature step end. Refactored _delay_ms() and square() for better portability.
- Fixed a premature step end bug dating back to Simen's 0.7b edge
version is fixed, from which this code is forked from. Caused by Timer2
constantly overflowing calling the Step Reset Interrupt every 128usec.
Now Timer2 is always disabled after a step end and should free up some
cycles for the main program. Could be more than one way to fix this
problem. I'm open to suggestions.

- _delay_ms() refactored to accept only constants to comply with
current compilers. square() removed since not available with some
compilers.
2012-01-15 18:25:12 -07:00
Sonny Jeon
89a3b37e02 Extended position reporting with both home and work coordinates. Home position now retained after reset. Other minor changes/fixes.
- Grbl now tracks both home and work (G92) coordinate systems and does
live updates when G92 is called.
- Rudimentary home and work position status reporting. Works but still
under major construction.
- Updated the main streaming script. Has a disabled periodic timer for
querying status reports, disabled only because the Python timer doesn't
consistently restart after the script exits. Add here only for user
testing.
- Fixed a bug to prevent an endless serial_write loop during status
reports.
- Refactored the planner variables to make it more clear what they are
and make it easier for clear them.
2012-01-10 08:34:54 -07:00
Sonny Jeon
e8a6bfd179 Position reporting, refactored system variables, serial print fixes, updated streaming scripts.
- Added machine position reporting to status queries. This will be
further developed with part positioning/offsets and maintaining
location upon reset.

- System variables refactored into a global struct for better
readability.

- Removed old obsolete Ruby streaming scripts. These were no longer
compatible. Updated Python streaming scripts.

- Fixed printFloat() and other printing functions.

- Decreased planner buffer back to 18 blocks and increased TX serial
buffer to 64 bytes. Need the memory space for future developments.

- Begun adding run-time modes to grbl, where block delete toggle, mm/in
reporting modes, jog modes, etc can be set during runtime. Will be
fleshed out and placed into EEPROM when everything is added.
2012-01-06 10:10:41 -07:00
Sonny Jeon
03e2ca7cd5 Initial v0.8 ALPHA commit. Features multi-tasking run-time command execution (feed hold, cycle start, reset, status query). Extensive re-structuring of code for future features.
- ALPHA status. - Multitasking ability with run-time command executions
for real-time control and feedback. - Decelerating feed hold and resume
during operation. - System abort/reset, which immediately kills all
movement and re-initializes grbl. - Re-structured grbl to easily allow
for new features: Status reporting, jogging, backlash compensation. (To
be completed in the following releases.) - Resized TX/RX serial buffers
(32/128 bytes) - Increased planner buffer size to 20 blocks. - Updated
documentation.
2011-12-08 18:47:48 -07:00
Sonny Jeon
9141ad2825 Third time's a charm! No more deceleration issues! Updated grbl version and settings. General cleanup.
- Fleshed out the original idea to completely remove the long slope at
the end of deceleration issue. This third time should absolutely
eliminate it.
- Changed the acceleration setting to kept as mm/min^2 internally,
since this was creating unneccessary additional computation in the
planner. Human readable value kept at mm/sec^2.
- Updated grbl version 0.7d and settings version to 4. NOTE: Please
check settings after update. These may have changed, but shouldn't.
- Before updating the new features (pause, e-stop, federate override,
etc), the edge branch will soon be merged with the master, barring any
immediate issues that people may have, and the edge branch will be the
testing ground for the new grbl version 0.8.
2011-10-11 20:51:04 -06:00
Sonny Jeon
2be0d66872 Fixed long slope at deceleration issue. Moved things into config.h. New MINIMUM_PLANNER_SPEED parameter.
- The long standing issue of a long slope at deceleration is likely
fixed. The stepper program was not tracking and timing the end of
acceleration and start of deceleration exactly and now is fixed to
start and stop on time. Also, to ensure a better acceleration curve fit
used by the planner, the stepper program delays the start of the
accelerations by a half trapezoid tick to employ the midpoint rule. -
Settings version 3 migration (not fully tested, but should work) -
Added a MINIMUM_PLANNER_SPEED user-defined parameter to planner to let
a user change this if problems arise for some reason. - Moved all
user-definable #define parameters into config.h with clear comments on
what they do and recommendations of how to change them. - Minor
housekeeping.
2011-09-24 07:46:41 -06:00
Sonny J
6de805441f Fixed minor bugs in planner. Increased max dwell time. Long slope bug stop-gap solution note.
- Fixed the planner TODO regarding minimum nominal speeds. Re-arranged
calculations to be both more efficient and guaranteed to be greater
than zero. - Missed a parenthesis location on the rate_delta
calculation. Should fix a nearly in-perceptible issue with incorrect
acceleration ramping in diagonal directions. - Increased maximum dwell
time from 6.5sec to an 18hour max. A crazy amount more, but that's how
the math works out. - Converted the internal feedrate values to mm/min
only, as it was switching between mm/min to mm/sec and back to mm/min.
Also added a feedrate > 0 check in gcode.c. - Identified the long slope
at the end of rapid de/ac-celerations noted by stephanix. Problem with
the numerical integration truncation error between the exact solution
of estimate_acceleration_distance and how grbl actually performs the
acceleration ramps discretely. Increasing the
ACCELERATION_TICKS_PER_SECOND in config.h helps fix this problem.
Investigating further.
2011-09-18 05:36:55 -06:00
Sonny J
110faae986 More '%' modulo opertor removals and some housecleaning.
- Serial functions contained quite a few modulo operations that would
be executed with high frequency when streaming. AVR processors are very
slow when operating these. In one test on the Arduino forums, it showed
about a 15x slow down compared to a simple if-then statement. -
Clarified some variable names and types and comments.
2011-09-15 20:32:15 -06:00
Sonny J
4d03c4febc Further planner improvements and misc minor bug fixes. Memory savings and increased buffer size.
- Update grbl version and settings version to automatically reset
eeprom. FYI, this will reset your grbl settings. - Saved
3*BLOCK_BUFFER_SIZE doubles in static memory by removing obsolete
variables: speed_x, speed_y, and speed_z. - Increased buffer size
conservatively to 18 from 16. (Probably can do 20). - Removed expensive!
modulo operator from block indexing function. Reduces significant
computational overhead. - Re-organized some sqrt() calls to be more
efficient during time critical planning cases, rather than non-time
critical. - Minor bug fix in planner max junction velocity logic. -
Simplified arc logic and removed need to multiply for CW or CCW
direction.
2011-09-13 21:57:16 -06:00
Sonny J
ffcc3470a3 Optimized planner re-write. Significantly faster. Full arc support enabled by rotation matrix approach.
- Significant improvements in the planner. Removed or reordered
repetitive and expensive calculations by order of importance:
recalculating unchanged blocks, trig functions [sin(), cos(), tan()],
sqrt(), divides, and multiplications. Blocks long enough for nominal
speed to be guaranteed to be reached ignored by planner. Done by
introducing two uint8_t flags per block. Reduced computational overhead
by an order of magnitude.   - Arc motion generation completely
re-written and optimized. Now runs with acceleration planner. Removed
all but one trig function (atan2) from initialization. Streamlined
computations. Segment target locations generated by vector
transformation and small angle approximation. Arc path correction
implemented for accumulated error of approximation and single precision
calculation of Arduino. Bug fix in message passing.
2011-09-06 19:39:14 -06:00
Simen Svale Skogsrud
c0b4b8309a cleaned up serial completing support for non blocking tx and refactoring formatting functions into a new module 'print' 2011-06-03 15:28:14 +02:00
Simen Svale Skogsrud
defabc80ed renamed wiring_serial to serial to reflect its complete remake 2011-05-31 22:45:38 +02:00
Simen Svale Skogsrud
60f417b570 fixed a double rounding error compensation bug in mc_arc thanks to Etienne Chové 2011-02-23 20:06:55 +01:00
Simen Svale Skogsrud
2c913a00bd acceleration-Grbl now works with atmega 168 by disabling arc motion 2011-02-20 22:13:31 +01:00
Simen Svale Skogsrud
6edbbe322c lowercased boolean constants 2011-02-18 23:04:12 +01:00
Simen Svale Skogsrud
ff73645a14 cleanup, protected some more module variables as static 2011-02-12 00:03:58 +01:00
Simen Svale Skogsrud
33f014aa74 eliminated an abstraction violation where motion_control needed position information from the planner (untested) 2011-02-11 23:01:16 +01:00
Simen Svale Skogsrud
480f898c2b eliminated the mc_line-method and replaced it with a macro forwarding calls directly to the planner (untested) 2011-02-11 00:53:00 +01:00
Simen Svale Skogsrud
6dc81b41c9 formatting + moved current position getter to planner 2011-02-11 00:44:18 +01:00
Simen Svale Skogsrud
07f8623098 smoothed a wrinkle 2011-02-11 00:36:40 +01:00
Simen Svale Skogsrud
a4c64945e0 refactored stepper_plan -> planner (untested) 2011-02-11 00:34:53 +01:00
Simen Svale Skogsrud
c42741032f Refactored line buffering to eliminate state from motion control and centralize tracking of position. UNTESTED: NEEDS TESTING 2011-02-06 23:23:34 +01:00
Simen Svale Skogsrud
cdcc7bf86e cleaned up methods for enabling/disabling acceleration manger 2011-02-06 22:25:01 +01:00
Simen Svale Skogsrud
6d3ff506e8 refactored compile time settings back into a new file called config.h 2011-02-05 00:55:37 +01:00
Simen Svale Skogsrud
d00947a23a renamed config.* to settings.* 2011-02-05 00:45:41 +01:00
Simen Svale Skogsrud
f4b9da1ecb acceleration management is disabled during arc-motions until the two can be made to play nice together 2011-02-03 13:12:47 +01:00