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[Emc-commit] v2_3_branch: Remove incorrect Encoder description.
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From: John T. <gi...@gi...> - 2009-09-26 22:21:42
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Remove incorrect Encoder description. It is covered in the Integrators Manual. Signed-off-by: John Thornton <bj...@gm...> http://git.linuxcnc.org/?p=emc2.git;a=commitdiff;h=78b3c13 --- docs/src/hal/general_ref.lyx | 279 ------------------------------------------ 1 files changed, 0 insertions(+), 279 deletions(-) diff --git a/docs/src/hal/general_ref.lyx b/docs/src/hal/general_ref.lyx index bfaef01..788969c 100644 --- a/docs/src/hal/general_ref.lyx +++ b/docs/src/hal/general_ref.lyx @@ -1109,283 +1109,4 @@ offset \series default . If enable is false, then output 0. -\layout Section - - -\begin_inset LatexCommand \label{sec:CanonEncoder} - -\end_inset - -Encoder -\layout Standard - -The canonical encoder interface (I/O type field: -\family typewriter -\series bold - encoder -\family default -\series default - ) provides the functionality needed for homing to an index pulse and doing - spindle synchronization, as well as basic position and/or velocity control. - This interface should be implementable regardless of the actual underlying - hardware, although some hardware will provide -\begin_inset Quotes eld -\end_inset - -better -\begin_inset Quotes erd -\end_inset - - results. - (For example, capture the index position to +/- 1 count while moving faster, - or have less jitter on the velocity pin.) -\layout Subsection - -Pins -\layout Itemize - - -\shape smallcaps -(s32) -\family typewriter -\series bold -\shape default - count -\family default -\series default - -- Encoder value in counts. -\layout Itemize - - -\shape smallcaps -(float) -\shape default - -\family typewriter -\series bold -position -\family default -\series default - -- Encoder value in position units (see parameter -\begin_inset Quotes eld -\end_inset - -scale -\begin_inset Quotes erd -\end_inset - -). - -\layout Itemize - - -\shape smallcaps -(float) -\shape default - -\family typewriter -\series bold -velocity -\family default -\series default - -- Velocity in position units per second. -\layout Itemize - - -\shape smallcaps -(bit) -\shape default - -\family typewriter -\series bold -reset -\family default -\series default - -- When True, force counter to zero. -\layout Itemize - - -\shape smallcaps -(bit) -\shape default - -\family typewriter -\series bold -index-enable -\family default -\series default - -- (bidirectional) When True, reset to zero on next index pulse, and set - pin False. -\layout Standard - -The -\begin_inset Quotes eld -\end_inset - -index-enable -\begin_inset Quotes erd -\end_inset - - pin is bi-directional, and might require a little more explanation. - If -\begin_inset Quotes eld -\end_inset - -index-enable -\begin_inset Quotes erd -\end_inset - - is False, the index channel of the encoder will be ignored, and the counter - will count normally. - The encoder driver will never set -\begin_inset Quotes eld -\end_inset - -index-enable -\begin_inset Quotes erd -\end_inset - - True. - However, some other component may do so. - If -\begin_inset Quotes eld -\end_inset - -index-enable -\begin_inset Quotes erd -\end_inset - - is True, then when the next index pulse arrives, the encoder counter will - be reset to zero, and the driver will set -\begin_inset Quotes eld -\end_inset - -index-enable -\begin_inset Quotes erd -\end_inset - - False. - That will let the other component know that an index pulse arrived. - This is a form of handshaking - the other component sets -\begin_inset Quotes eld -\end_inset - -index-enable -\begin_inset Quotes erd -\end_inset - - True to request a index pulse reset, and the driver sets it False when - the request has been satisfied. -\layout Subsection - -Parameters -\layout Itemize - - -\shape smallcaps -(float) -\shape default - -\family typewriter -\series bold -scale -\family default -\series default - -- The scale factor used to convert counts to position units. - It is in -\begin_inset Quotes eld -\end_inset - -counts per position unit -\begin_inset Quotes erd -\end_inset - -. - For example, if you have a 512 count per turn encoder on a 5 turn per inch - screw, the scale should be 512*5 = 2560 counts per inch, which will result - in -\begin_inset Quotes eld -\end_inset - -position -\begin_inset Quotes erd -\end_inset - - in inches and -\begin_inset Quotes eld -\end_inset - -velocity -\begin_inset Quotes erd -\end_inset - - in inches per second. -\layout Itemize - - -\shape smallcaps -(float) -\shape default - -\family typewriter -\series bold -max-index-vel -\family default -\series default - -- (optional) The maximum velocity (in position units per second) at which - the encoder can reset on an index pulse with +/- 1 count accuracy. - This is an output from the encoder driver, and is intended to tell the - user something about the hardware capabilities. - Some hardware can reset the counter at the exact moment the index pulse - arrives. - Other hardware can only tell that an index pulse arrived sometime since - the last time the read function was called. - For the latter, +/- 1 count accuracy can only be achieved if the encoder - advances by 1 count or less between calls to the read function. -\layout Itemize - - -\shape smallcaps -(float) -\shape default - -\family typewriter -\series bold -velocity-resolution -\family default -\series default - -- (optional) The resolution of the velocity output, in position units - per second. - This is an output from the encoder driver, and is intended to tell the - user something about the hardware capabilities. - The simplest implementation of the velocity output is the change in postion - from one call of the read function to the next, divided by the time between - calls. - This yields a rather coarse velocity signal that jitters back and forth - between widely spaced possible values (quantization error). - However, some hardware captures both the counts and the exact time when - a count occurres (possibly with a very high resolution clock). - That data allows the driver to calculate velocity with finer resolution - and less jitter. - -\layout Subsection - -Functions -\layout Standard - -There is only one function, to read the encoder(s). - -\layout Itemize - - -\family typewriter -\noun on -(funct) -\noun default - -\series bold -read -\family default -\series default - -- Capture counts, update position and velocity. \the_end |