[Emc-users] Mb2hal?

[Todd Zuercher]

Anyone out there ever try to use a Fuji Frenic VFD with Mb2hal?

Todd Zuercher
P. Graham Dunn Inc.
630 Henry Street
Dalton, Ohio 44618
Phone:  (330)828-2105ext. 2031


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Re: [Emc-users] Home with home switch and index

[Feral Engineer]

I had a go with this a while back with my emco lathe. I wanted to home
against a switch, trigger an index pulse from a prox and call it zero. 2.8
wouldn't let me because it was looking for an encoder reset signal that I
didn't have, but 2.9 included a new function called something like
no_home_index or something like that which worked perfectly.

Here's a video

https://youtu.be/6_CrfcJXfDw

Phil T.
The Feral Engineer

Check out my LinuxCNC tutorials, machine builds and other antics at
www.youtube.com/c/theferalengineer

Help support my channel efforts and coffee addiction:
www.patreon.com/theferalengineer

On Tue, Sep 28, 2021, 3:59 PM Nicklas SB Karlsson  wrote:

> Seems to have some accuracy problem with home switch and need to improve.
>
> Reading the manual I have not been able to figure out if homing with
> home switch and index what happen if home switch is located close to
> index pulse. It might happen more or less random index pulse is
> sometimes triggered to the left of home switch other times one turn away
> to the right or the other way.
>
>
> Nicklas Karlsson
>
>
>
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Re: [Emc-users] Home with home switch and index

[Peter C. Wallace]

On Tue, 28 Sep 2021, Nicklas SB Karlsson wrote:


Date: Tue, 28 Sep 2021 21:31:24 +0200
From: Nicklas SB Karlsson 
Reply-To: "Enhanced Machine Controller (EMC)"

To: emc-users@lists.sourceforge.net
Subject: [Emc-users] Home with home switch and index

Seems to have some accuracy problem with home switch and need to improve.

Reading the manual I have not been able to figure out if homing with home 
switch and index what happen if home switch is located close to index pulse. 
It might happen more or less random index pulse is sometimes triggered to 
the left of home switch other times one turn away to the right or the other 
way.



Nicklas Karlsson



I would think its best to have the index about 1/2 a screw turn from the
home switch to avoid this kind of uncertainty.





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Peter Wallace
Mesa Electronics




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[Emc-users] Home with home switch and index

[Nicklas SB Karlsson]

Seems to have some accuracy problem with home switch and need to improve.

Reading the manual I have not been able to figure out if homing with 
home switch and index what happen if home switch is located close to 
index pulse. It might happen more or less random index pulse is 
sometimes triggered to the left of home switch other times one turn away 
to the right or the other way.



Nicklas Karlsson



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Re: [Emc-users] more dc servo questions

[Gene Heskett]

On Tuesday 28 September 2021 13:43:54 John Figie wrote:

>   Gene,
>
> So It seems like you have verified that the PSU shutdown is not caused
> by a shoot through current in the H bridge and that is good.
> Now if the motor is running at 24V and you instantly reverse the power
> supply, the current going into the motor will not instantly reverse
> direction because of the motor inductance. But if the inertia is large
> compared to the inductance (large in terms of stored energy) then like
> you say, the current will soon get very large as you will have
> essentially 48V (24 from PSU and 24 from back EMF) across the winding,
> limited only by the resistance.
>
> Now I am working on making some torque mode drives for my lathe
> retrofit. But I would like to see if I can make a decent motor and
> drive simulation using LTSpice. I already have what I think is a
> reasonable motor model. I intend to share the simulation model once I
> am confident in it. It can also be used to show any benefit in true
> torque mode, where the current is the command input to the drive,
> rather than voltage mode - what I think you have. I have found that if
> a simulation can be set up and validated it gives much more insight
> into a particular problem - you can make changes quickly and you can
> measure things that would be otherwise very difficult.
>
> It would be cool if I could get more info about your motor and
> mechanics.
>
> Like:
>
> No Load Speed - maybe not feasible for you since you would need to
> take your machine apart.

My best estimate would still be a WAG.

> Nominal voltage and speed
24 volts, 100 watt rated, but I suspect from the heat rise that would be 
an ICAS rating. Service target is a chain driven estate driveway gate 
and one open/close wouldn't be anywhere near CCS.

> Stall current
Since the psu is a 300 watt model and doesn't crowbar at the limited 
accells I can use, I'll say a WAG at 10 to 12 amps. 

> Stall torque
unk, more than enough to turn the bs-1. Including I believe with a 
cutting load applied

> DC resistance

That I can get.

> Inductance

I have an esr meter that might report that, none of the several dvm's I 
have does inductance. 

> Inertia of rotor and worm - that one may be hard to find. but maybe it
> can be estimated by the mass, and diameter of the armature and
> connected load. The mass on the worm gear side will probably not be
> significant because of the high gear ratios.
>
> Regards,
>
> John

I'll get back with anything else I can measure but I've got some pill 
shopping to do yet today, scripts running out etc.

Thanks John.
>
>
>
>
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Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] more dc servo questions

[John Figie]

  Gene,

So It seems like you have verified that the PSU shutdown is not caused by a
shoot through current in the H bridge and that is good.
Now if the motor is running at 24V and you instantly reverse the power
supply, the current going into the motor will not instantly reverse
direction because of the motor inductance. But if the inertia is large
compared to the inductance (large in terms of stored energy) then like you
say, the current will soon get very large as you will have essentially 48V
(24 from PSU and 24 from back EMF) across the winding, limited only by the
resistance.

Now I am working on making some torque mode drives for my lathe retrofit.
But I would like to see if I can make a decent motor and drive simulation
using LTSpice. I already have what I think is a reasonable motor model. I
intend to share the simulation model once I am confident in it. It can also
be used to show any benefit in true torque mode, where the current is the
command input to the drive, rather than voltage mode - what I think you
have. I have found that if a simulation can be set up and validated it
gives much more insight into a particular problem - you can make changes
quickly and you can measure things that would be otherwise very difficult.

It would be cool if I could get more info about your motor and mechanics.

Like:

No Load Speed - maybe not feasible for you since you would need to take
your machine apart.
Nominal voltage and speed
Stall current
Stall torque
DC resistance
Inductance
Inertia of rotor and worm - that one may be hard to find. but maybe it can
be estimated by the mass, and diameter of the armature and connected load.
The mass on the worm gear side will probably not be significant because of
the high gear ratios.

Regards,

John



>
>

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