On Wed, 25 May 2011, andy pugh wrote:
Date: Wed, 25 May 2011 19:10:35 +0100
From: andy pugh <[email protected]>
Reply-To: "Enhanced Machine Controller (EMC)"
<[email protected]>
To: "Enhanced Machine Controller (EMC)" <[email protected]>
Subject: Re: [Emc-users] Hydraulic Position control with EMC2
On 25 May 2011 18:45, Dave <[email protected]> wrote:
How would that SSI to quadrature encoder work? The nice thing about
SSI is that when the power goes on, the motion system knows exactly
where it is without homing or moving.
The way my Arduino-based resolver-to-quadrature converter works is
that when you turn it on, it immediately counts up to the current
position at the fastest rate it can. As long as the quadrature counter
powers up before the converter, and both before the motion
controllers, then you retain the absolute position advantage.
In fact, it is probably fairly easy to use an Arduino for SSI.
<google>
Yes, there is code here.
http://reprap.org/wiki/Magnetic_Rotary_Encoder_1.0
It does it with bit-bashing, and I suspect there are better ways, but
it is a cheap solution.
If you had a position start input pin, you could avoid any startup race
conditions by outputing the counts only after the start signal was removed.
The start pin could be common to all axis and manipulated by EMC along with
the quadrature counter clear so all quadrature counters were in sync with the
absolute position...
--
atp
"Torque wrenches are for the obedience of fools and the guidance of wise men"
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With the market-leading solution for virtual backup and recovery,
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