On 4/10/20 1:01 PM, Peter C. Wallace wrote:
On Fri, 10 Apr 2020, Leonardo Marsaglia wrote:
Date: Fri, 10 Apr 2020 16:50:15 -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: Re: [Emc-users] Home use index problem (In step + dir mode)
Thank you Peter for your quick response.
I just checked my ini file and the entry is like this HOME_USE_INDEX
= YES.
I also have set SEARCH VEL and LATCH VEL at 10 and 5 respectively. I
even
inverter the differential pins on the Z pulse just to be sure they
weren't
backwards but the behaviour is the same. I'll keep playing with it
but for
now I can only set the index pulse to on manually.
Do you have a home switch and is it working?
If you want to home to index only you must set HOME_SEARCH_VELOCITY to 0
Just to muddy the water: I don't use the home switch, just manually
adjust starting point so a laser pointer is coincident with a hole in a
tab (x & y). Kick off homing and it picks up the index and moves to the
appropriate axis zero. It is about as lazy as one can get and still have
it work. For Z I set the cam so it jsut touches the tab on the limit
switch.
Dave
Is it talking about using the step mode in velocity to drive the
servo in
velocity mode? Because I'm using it in velocity mode but just as
suggested
to close the loop internally and gain more accuracy at the output. Not
closing the loop with the motor encoder.
If you are using a pncconf generated hal file, the stepgen will always be
in velocity mode. though it may have internal (from stepgen) or
external (from encoder) position feedback
Anyway these servos I don't think can't take pulses as velocity
command. I
have the hardware to output +/- 10 volts but I rather use them as
step and
direction to avoid mounting encoders on the screws. I don't think
using the
encoder on the motor to be the best idea because the motor is coupled to
the ballscrew by means of a toothed belt.
Do the servos have a emulated encopder output (you mentioned a Z
signal, is that from the drive?)
El vie., 10 abr. 2020 a las 16:31, Peter C. Wallace (<p...@mesanet.com>)
On Fri, 10 Apr 2020, Leonardo Marsaglia wrote:
> Date: Fri, 10 Apr 2020 16:11:18 -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] Home use index problem (In step + dir mode)
>
> Hello guys again,
>
> I'm testing the homing of the X axis with a push button and that works
> except when the index pulse has to trigger. That never happens.
>
> I'm using the 7i52S to move my servo with step + dir for position
command
> right to the drive. In LCNC the stepper is working in velocity mode
like
> it's recommended. I'm reading the Z pulse of the servo motor thru the
same
> 7i52S using one of the encoder inputs. I'm only reading Z because I
don't
> need A and B for my purposes now.
>
> The problem is, I can't make the homing with index feature to work.
I can
> see the index pulse triggering to FALSE when the shaft completes the
turn,
> and I even set the pin to TRUE again manually to see if the homing
sequence
> stops, but the motor keeps turning at final velocity waiting for the
index
> to happen.
>
> I'm even monitoring the joint.0.index-enable pin with Halmeter to
be sure
> the signal is linked and it's working ok. The only thing I find
strange
is
> that I need to set the index-enable pin to TRUE by myself. The homing
> sequence doesn't seem to be doing that.
It sounds like you dont have homing to index enabled in your ini file
(if motion does not set index-enable, it will not look for it going
false)
That said I dont think this will work correctly on step/dir systems
without
encoder feedback. The reason is that on index detection, the reported
position
on encoders is zeroed, (and motion expects this behavior) this is not
done
on
stepgens. The hardware for capturing the index and the stepgen count at
index is in the firmware, (allowing stepgens to emulate encoder
behaviour)
but the hm2 driver has no support for this option.
>
> I'm using LCNC 2.8.0-pre1-5538-g21d7db0. I was thingking maybe this
> feature is not allowed with steppers and that's why I can't use it?
But
the
> homing sequence is actually waiting for that index pulse so I don't
think
> this is the case.
>
> I'm surely missing something here, but without your help I'm a
little bit
> lost.
>
> As always thank you for your support!
>
> _______________________________________________
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>
Peter Wallace
Mesa Electronics
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Peter Wallace
Mesa Electronics
(\__/)
(='.'=) This is Bunny. Copy and paste bunny into your
(")_(") signature to help him gain world domination.
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