On Sat, 21 Mar 2020, Leonardo Marsaglia wrote:
Date: Sat, 21 Mar 2020 00:48:46 -0300
From: Leonardo Marsaglia <ldmarsag...@gmail.com>
Reply-To: "Enhanced Machine Controller (EMC)"
<emc-users@lists.sourceforge.net>
To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net>
Subject: [Emc-users] Question about index pulse on high resolution encoder
Hello guys,
I'm testing a phisical encoder to simulate how the spindle will work with
the external offsets. So far so good but I need to clarify something that I
suspect. Here it comes:
The encoder I'm testing is an ERN471 from Heidenhain. A beast of encoder.
It says 5.000 line counts on the datasheet but also says it outputs 125.000
signal periods per revolution, so when I read it in LinuxCNC with a scale
of 1 I find that I'm having 500.000 pulses per turn. A lot of resolution.
I'm scaling it to 1024 since this is what I have on the Mazak.
My concern is (and I think this is to be expected) that I have missing
index pulses if I rotate the encoder too fast with my fingers. I tried to
use a shorter servo-period and that seemed to improve things a little but
not solving the problem always.
Is this what's happening? Should I not expect this behaviour with the 1024
PPR encoder and the spindle turning at about 200 RPM ?
I would like to hear your thoughts just to be relaxed, since a missing
index pulse on this kind of processes is likely to break the tool and
spoil the part.
Thanks as always!
Thats looks to be a 5000 line (20000 CPR) encoder with a built in 25X
interpolator to 500000 (20000x25) counts per turn, I would not expect
it to work at high speeds, Depending on interface hardware and setup
How can you use a scale of 1024? Isnt the encoder a fixed 500000 CPR device?
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Peter Wallace
Mesa Electronics
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