Re: [Emc-users] Suggestions for a retrofit.

[Andy Pugh]

> On 14 Sep 2021, at 22:04, John Figie  wrote:
> 
> so I am wondering how one would go about
> configuring LinuxCNC for the STMBL.

It’s surprisingly simple at the HAL end:

https://github.com/rene-dev/stmbl/blob/master/docs/linuxcnc/stmbl.hal


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Re: [Emc-users] Suggestions for a retrofit.

[John Dammeyer]

Hi John,
There are a few people on this list who have all 4 or even 5 axis running with 
STMBL.   Andy Pugh, from whom I bought my boards, has it on his A axis. 

This link takes you to the conversation about it.  There are a few kits still 
being made.

https://gitter.im/rene-dev/stmbl

Designers Rene Hall and Nico Stute have been very helpful.  They are in Germany 
so mind the time zone differences if you expect an answer.

John Dammeyer

> -Original Message-
> From: John Figie [mailto:zephyr9...@gmail.com]
> Sent: September-14-21 1:01 PM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Suggestions for a retrofit.
> 
> John,
> 
> When STMBL is using the SSERIAL interface is the drive operating in
> position mode and receiving periodic position commands from the motion
> planner in LinuxCNC? If so, then I would think that the performance would
> be quite good with updates at 1mSec rates which would not be too difficult
> for LinuxCNC. When I follow the link about the
> http://linuxcnc.org/docs/html/man/man9/sserial.9.html there is no mention
> of the STMBL as a device, so I am wondering how one would go about
> configuring LinuxCNC for the STMBL.
> 
> But also it looks like a bit of work to acquire all of the parts and build
> one of these STMBLs unless someone is selling the PCBs and other parts.
> Did you build your own STMBLs?
> 
> The STMBL looks pretty nice and it looks like a lot of effort has gone into
> it.
> 
> Regards,
> 
> John Figie
> 
> 
> On Mon, Sep 13, 2021 at 6:09 PM John Dammeyer 
> wrote:
> 
> > Hi John,
> > Yes, I use step/dir for a harmonic drive AC Servo that as yet still has to
> > be put into a casting and married to a face plate.   For now it sits on the
> > cart beside the mill and I can make the A axis turn.
> > http://www.autoartisans.com/mill/HarmonicDrive/D8X_5784_Plastic_Mount.jpg
> > I did try to get one of my DC Servos also working with a second STMBL.
> > However I had trouble tuning it and the HP_UHU (105VDC power supply) has
> > been more than adequate so for now I'm staying with that.
> >
> > I used step/dir because initially my PC is dual boot and I wanted both
> > MACH3 and LCNC to work.  Along with also a BeagleBone with a cape for
> > MachineKit so Parallel port and BoB were mandatory.  That excludes any of
> > the smart serial unless it terminated in a standard Parallel port
> > configuration.
> >
> > John Dammeyer
> >
> > > -----Original Message-
> > > From: John Figie [mailto:zephyr9...@gmail.com]
> > > Sent: September-13-21 3:39 PM
> > > To: Enhanced Machine Controller (EMC)
> > > Subject: Re: [Emc-users] Suggestions for a retrofit.
> > >
> > > John,
> > >
> > > Thanks for the info so it looks like the Mesa Smart Serial interface can
> > be
> > > used with this drive. If I understand correctly the SSERIAL interface
> > comes
> > > from one of the mesa FPGA I/O cards and connects to the STMBL drive. (I
> > > mean that is one way to interface to the STMBL drive). Otherwise a step
> > and
> > > direction or a quadrature input would be used with the STMBL drive.
> > >
> > > On Mon, Sep 13, 2021 at 3:53 PM John Dammeyer 
> > > wrote:
> > >
> > > > John,
> > > > The work has already been done with the STMBL project.  The biggest
> > issue
> > > > with that one was the 3 phase motor driver was discontinued so that
> > caused
> > > > a bit of panic.  But it's an open source project that can use step/dir
> > or
> > > > smart serial from the MESA boards.
> > > >
> > > > https://github.com/rene-dev/stmbl
> > > >
> > > > John Dammeyer
> > > >
> > > > > -Original Message-
> > > > > From: John Figie [mailto:zephyr9...@gmail.com]
> > > > > Sent: September-13-21 1:32 PM
> > > > > To: Enhanced Machine Controller (EMC)
> > > > > Subject: Re: [Emc-users] Suggestions for a retrofit.
> > > > >
> > > > > It's been a long time and I have not made much progress. Except now
> > I am
> > > > > retired from my job as an electrical engineer. In my job I developed
> > > > > industrial PMAC servo drives for a leading industrial controls
> > > > manufacturer
> > > > > located in Milwaukee. So to solve my servo amplifier problem I have
> > > > decided
> > > > > to build my own and have already made significant progress. My
> > homemade
> > > > &g

Re: [Emc-users] Suggestions for a retrofit.

[John Figie]

John,

When STMBL is using the SSERIAL interface is the drive operating in
position mode and receiving periodic position commands from the motion
planner in LinuxCNC? If so, then I would think that the performance would
be quite good with updates at 1mSec rates which would not be too difficult
for LinuxCNC. When I follow the link about the
http://linuxcnc.org/docs/html/man/man9/sserial.9.html there is no mention
of the STMBL as a device, so I am wondering how one would go about
configuring LinuxCNC for the STMBL.

But also it looks like a bit of work to acquire all of the parts and build
one of these STMBLs unless someone is selling the PCBs and other parts.
Did you build your own STMBLs?

The STMBL looks pretty nice and it looks like a lot of effort has gone into
it.

Regards,

John Figie


On Mon, Sep 13, 2021 at 6:09 PM John Dammeyer 
wrote:

> Hi John,
> Yes, I use step/dir for a harmonic drive AC Servo that as yet still has to
> be put into a casting and married to a face plate.   For now it sits on the
> cart beside the mill and I can make the A axis turn.
> http://www.autoartisans.com/mill/HarmonicDrive/D8X_5784_Plastic_Mount.jpg
> I did try to get one of my DC Servos also working with a second STMBL.
> However I had trouble tuning it and the HP_UHU (105VDC power supply) has
> been more than adequate so for now I'm staying with that.
>
> I used step/dir because initially my PC is dual boot and I wanted both
> MACH3 and LCNC to work.  Along with also a BeagleBone with a cape for
> MachineKit so Parallel port and BoB were mandatory.  That excludes any of
> the smart serial unless it terminated in a standard Parallel port
> configuration.
>
> John Dammeyer
>
> > -Original Message-
> > From: John Figie [mailto:zephyr9...@gmail.com]
> > Sent: September-13-21 3:39 PM
> > To: Enhanced Machine Controller (EMC)
> > Subject: Re: [Emc-users] Suggestions for a retrofit.
> >
> > John,
> >
> > Thanks for the info so it looks like the Mesa Smart Serial interface can
> be
> > used with this drive. If I understand correctly the SSERIAL interface
> comes
> > from one of the mesa FPGA I/O cards and connects to the STMBL drive. (I
> > mean that is one way to interface to the STMBL drive). Otherwise a step
> and
> > direction or a quadrature input would be used with the STMBL drive.
> >
> > On Mon, Sep 13, 2021 at 3:53 PM John Dammeyer 
> > wrote:
> >
> > > John,
> > > The work has already been done with the STMBL project.  The biggest
> issue
> > > with that one was the 3 phase motor driver was discontinued so that
> caused
> > > a bit of panic.  But it's an open source project that can use step/dir
> or
> > > smart serial from the MESA boards.
> > >
> > > https://github.com/rene-dev/stmbl
> > >
> > > John Dammeyer
> > >
> > > > -Original Message-
> > > > From: John Figie [mailto:zephyr9...@gmail.com]
> > > > Sent: September-13-21 1:32 PM
> > > > To: Enhanced Machine Controller (EMC)
> > > > Subject: Re: [Emc-users] Suggestions for a retrofit.
> > > >
> > > > It's been a long time and I have not made much progress. Except now
> I am
> > > > retired from my job as an electrical engineer. In my job I developed
> > > > industrial PMAC servo drives for a leading industrial controls
> > > manufacturer
> > > > located in Milwaukee. So to solve my servo amplifier problem I have
> > > decided
> > > > to build my own and have already made significant progress. My
> homemade
> > > > drives will be able to run either DC brush motors or in the future AC
> > > > motors. I have a basic torque mode drive in the process of
> development
> > > but
> > > > I am thinking I would like the drive to be a velocity mode drive.
> > > >
> > > > My question now is how to interface to LinuxCNC? I really want to
> connect
> > > > all of my I/O using the mesa ethernet cards like the 7I80. From the
> 7I80
> > > it
> > > > looks like there is a way to have SPI interfaces. It seems like the
> SPI
> > > > would be one way to make a simple digital interface to my drives. The
> > > 7I80
> > > > would send velocity commands and velocity feedback to the drives. The
> > > > drives would return status and fault information back to LinuxCNC.
> > > >
> > > > Is it possible for me to use the SPI interfaces with LinuxCNC in the
> way
> > > I
> > > > have described? If so, how does one go about setting up the SPI
> > > int

Re: [Emc-users] Suggestions for a retrofit.

[John Dammeyer]

Hi John,
Yes, I use step/dir for a harmonic drive AC Servo that as yet still has to be 
put into a casting and married to a face plate.   For now it sits on the cart 
beside the mill and I can make the A axis turn.
http://www.autoartisans.com/mill/HarmonicDrive/D8X_5784_Plastic_Mount.jpg
I did try to get one of my DC Servos also working with a second STMBL.  However 
I had trouble tuning it and the HP_UHU (105VDC power supply) has been more than 
adequate so for now I'm staying with that.

I used step/dir because initially my PC is dual boot and I wanted both MACH3 
and LCNC to work.  Along with also a BeagleBone with a cape for MachineKit so 
Parallel port and BoB were mandatory.  That excludes any of the smart serial 
unless it terminated in a standard Parallel port configuration.

John Dammeyer

> -Original Message-
> From: John Figie [mailto:zephyr9...@gmail.com]
> Sent: September-13-21 3:39 PM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Suggestions for a retrofit.
> 
> John,
> 
> Thanks for the info so it looks like the Mesa Smart Serial interface can be
> used with this drive. If I understand correctly the SSERIAL interface comes
> from one of the mesa FPGA I/O cards and connects to the STMBL drive. (I
> mean that is one way to interface to the STMBL drive). Otherwise a step and
> direction or a quadrature input would be used with the STMBL drive.
> 
> On Mon, Sep 13, 2021 at 3:53 PM John Dammeyer 
> wrote:
> 
> > John,
> > The work has already been done with the STMBL project.  The biggest issue
> > with that one was the 3 phase motor driver was discontinued so that caused
> > a bit of panic.  But it's an open source project that can use step/dir or
> > smart serial from the MESA boards.
> >
> > https://github.com/rene-dev/stmbl
> >
> > John Dammeyer
> >
> > > -Original Message-
> > > From: John Figie [mailto:zephyr9...@gmail.com]
> > > Sent: September-13-21 1:32 PM
> > > To: Enhanced Machine Controller (EMC)
> > > Subject: Re: [Emc-users] Suggestions for a retrofit.
> > >
> > > It's been a long time and I have not made much progress. Except now I am
> > > retired from my job as an electrical engineer. In my job I developed
> > > industrial PMAC servo drives for a leading industrial controls
> > manufacturer
> > > located in Milwaukee. So to solve my servo amplifier problem I have
> > decided
> > > to build my own and have already made significant progress. My homemade
> > > drives will be able to run either DC brush motors or in the future AC
> > > motors. I have a basic torque mode drive in the process of development
> > but
> > > I am thinking I would like the drive to be a velocity mode drive.
> > >
> > > My question now is how to interface to LinuxCNC? I really want to connect
> > > all of my I/O using the mesa ethernet cards like the 7I80. From the 7I80
> > it
> > > looks like there is a way to have SPI interfaces. It seems like the SPI
> > > would be one way to make a simple digital interface to my drives. The
> > 7I80
> > > would send velocity commands and velocity feedback to the drives. The
> > > drives would return status and fault information back to LinuxCNC.
> > >
> > > Is it possible for me to use the SPI interfaces with LinuxCNC in the way
> > I
> > > have described? If so, how does one go about setting up the SPI
> > interfaces
> > > and defining what data is passed back and forth? I am hoping Andy Pugh,
> > PCW
> > > or someone that knows can comment.
> > >
> > > LinuxCNC  <--Ethernet--> 7I80 -<> I/O inputs and outputs
> > >  |-<> SPI comms to
> > > servo amps  7I46?
> > >  | < encoder inputs
> > for
> > > axis and MPGs
> > >
> > > LinuxCNC with position loop only should be able to run with a slower
> > 1mSec
> > > or maybe 500uSec thread and no other high speed thread would be needed. I
> > > may however need to get the velocity feedback to my servo drive at a
> > faster
> > > rate for best/better performance.
> > >
> > > My reason for wanting Ethernet is I do not have to have my LinuxCNC PC on
> > > or embedded in my machine, it can be several meters away mounted where it
> > > won't be subject to heat and vibration. In addition with only one
> > > interface, a PC upgrade or repair / swap is easy.
> > >
> > >
> > > Regards,
> > >

Re: [Emc-users] Suggestions for a retrofit.

[John Figie]

John,

Thanks for the info so it looks like the Mesa Smart Serial interface can be
used with this drive. If I understand correctly the SSERIAL interface comes
from one of the mesa FPGA I/O cards and connects to the STMBL drive. (I
mean that is one way to interface to the STMBL drive). Otherwise a step and
direction or a quadrature input would be used with the STMBL drive.

On Mon, Sep 13, 2021 at 3:53 PM John Dammeyer 
wrote:

> John,
> The work has already been done with the STMBL project.  The biggest issue
> with that one was the 3 phase motor driver was discontinued so that caused
> a bit of panic.  But it's an open source project that can use step/dir or
> smart serial from the MESA boards.
>
> https://github.com/rene-dev/stmbl
>
> John Dammeyer
>
> > -Original Message-
> > From: John Figie [mailto:zephyr9...@gmail.com]
> > Sent: September-13-21 1:32 PM
> > To: Enhanced Machine Controller (EMC)
> > Subject: Re: [Emc-users] Suggestions for a retrofit.
> >
> > It's been a long time and I have not made much progress. Except now I am
> > retired from my job as an electrical engineer. In my job I developed
> > industrial PMAC servo drives for a leading industrial controls
> manufacturer
> > located in Milwaukee. So to solve my servo amplifier problem I have
> decided
> > to build my own and have already made significant progress. My homemade
> > drives will be able to run either DC brush motors or in the future AC
> > motors. I have a basic torque mode drive in the process of development
> but
> > I am thinking I would like the drive to be a velocity mode drive.
> >
> > My question now is how to interface to LinuxCNC? I really want to connect
> > all of my I/O using the mesa ethernet cards like the 7I80. From the 7I80
> it
> > looks like there is a way to have SPI interfaces. It seems like the SPI
> > would be one way to make a simple digital interface to my drives. The
> 7I80
> > would send velocity commands and velocity feedback to the drives. The
> > drives would return status and fault information back to LinuxCNC.
> >
> > Is it possible for me to use the SPI interfaces with LinuxCNC in the way
> I
> > have described? If so, how does one go about setting up the SPI
> interfaces
> > and defining what data is passed back and forth? I am hoping Andy Pugh,
> PCW
> > or someone that knows can comment.
> >
> > LinuxCNC  <--Ethernet--> 7I80 -<> I/O inputs and outputs
> >  |-<> SPI comms to
> > servo amps  7I46?
> >  | < encoder inputs
> for
> > axis and MPGs
> >
> > LinuxCNC with position loop only should be able to run with a slower
> 1mSec
> > or maybe 500uSec thread and no other high speed thread would be needed. I
> > may however need to get the velocity feedback to my servo drive at a
> faster
> > rate for best/better performance.
> >
> > My reason for wanting Ethernet is I do not have to have my LinuxCNC PC on
> > or embedded in my machine, it can be several meters away mounted where it
> > won't be subject to heat and vibration. In addition with only one
> > interface, a PC upgrade or repair / swap is easy.
> >
> >
> > Regards,
> >
> > John Figie
> >
> >
> > On Sun, Nov 29, 2020 at 6:47 PM dave engvall 
> wrote:
> >
> > >
> > >
> > > On 11/27/20 10:52 AM, andy pugh wrote:
> > > > On Fri, 27 Nov 2020 at 18:45, John Figie 
> wrote:
> > > >
> > > >> I think I am going to attempt to figure out what the parameters of
> my
> > > motor
> > > >> are and make a model to simulate my control loop. For hobby stuff I
> > > think
> > > >> LTspice may be good to model and simulate.
> > > > I am not sure what you hope to gain from a model. The data to
> populate
> > > > it would have to come from the actual machine, and at that point you
> > > > might as well just get on with it.
> > > >
> > > IIRC early versions of emc had motor parameters, etc tacked on the the
> > > end of the parameters for each axis. I don't know if any use was ever
> > > made of that.
> > > Maybe some of the early emc-ers with their memory still intact will
> > > remember as well as a model to insert the data into.
> > > Dave
> > >
> > > Just a comment: I've never had much success using torque mode: that
> > > doesn't mean I should not go back and revisit it.
> > >
&

Re: [Emc-users] Suggestions for a retrofit.

[John Dammeyer]

John,
The work has already been done with the STMBL project.  The biggest issue with 
that one was the 3 phase motor driver was discontinued so that caused a bit of 
panic.  But it's an open source project that can use step/dir or smart serial 
from the MESA boards.

https://github.com/rene-dev/stmbl

John Dammeyer

> -Original Message-
> From: John Figie [mailto:zephyr9...@gmail.com]
> Sent: September-13-21 1:32 PM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Suggestions for a retrofit.
> 
> It's been a long time and I have not made much progress. Except now I am
> retired from my job as an electrical engineer. In my job I developed
> industrial PMAC servo drives for a leading industrial controls manufacturer
> located in Milwaukee. So to solve my servo amplifier problem I have decided
> to build my own and have already made significant progress. My homemade
> drives will be able to run either DC brush motors or in the future AC
> motors. I have a basic torque mode drive in the process of development but
> I am thinking I would like the drive to be a velocity mode drive.
> 
> My question now is how to interface to LinuxCNC? I really want to connect
> all of my I/O using the mesa ethernet cards like the 7I80. From the 7I80 it
> looks like there is a way to have SPI interfaces. It seems like the SPI
> would be one way to make a simple digital interface to my drives. The 7I80
> would send velocity commands and velocity feedback to the drives. The
> drives would return status and fault information back to LinuxCNC.
> 
> Is it possible for me to use the SPI interfaces with LinuxCNC in the way I
> have described? If so, how does one go about setting up the SPI interfaces
> and defining what data is passed back and forth? I am hoping Andy Pugh, PCW
> or someone that knows can comment.
> 
> LinuxCNC  <--Ethernet--> 7I80 -<> I/O inputs and outputs
>  |-<> SPI comms to
> servo amps  7I46?
>  | < encoder inputs for
> axis and MPGs
> 
> LinuxCNC with position loop only should be able to run with a slower 1mSec
> or maybe 500uSec thread and no other high speed thread would be needed. I
> may however need to get the velocity feedback to my servo drive at a faster
> rate for best/better performance.
> 
> My reason for wanting Ethernet is I do not have to have my LinuxCNC PC on
> or embedded in my machine, it can be several meters away mounted where it
> won't be subject to heat and vibration. In addition with only one
> interface, a PC upgrade or repair / swap is easy.
> 
> 
> Regards,
> 
> John Figie
> 
> 
> On Sun, Nov 29, 2020 at 6:47 PM dave engvall  wrote:
> 
> >
> >
> > On 11/27/20 10:52 AM, andy pugh wrote:
> > > On Fri, 27 Nov 2020 at 18:45, John Figie  wrote:
> > >
> > >> I think I am going to attempt to figure out what the parameters of my
> > motor
> > >> are and make a model to simulate my control loop. For hobby stuff I
> > think
> > >> LTspice may be good to model and simulate.
> > > I am not sure what you hope to gain from a model. The data to populate
> > > it would have to come from the actual machine, and at that point you
> > > might as well just get on with it.
> > >
> > IIRC early versions of emc had motor parameters, etc tacked on the the
> > end of the parameters for each axis. I don't know if any use was ever
> > made of that.
> > Maybe some of the early emc-ers with their memory still intact will
> > remember as well as a model to insert the data into.
> > Dave
> >
> > Just a comment: I've never had much success using torque mode: that
> > doesn't mean I should not go back and revisit it.
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
> 
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users



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Re: [Emc-users] Suggestions for a retrofit.

[John Figie]

It's been a long time and I have not made much progress. Except now I am
retired from my job as an electrical engineer. In my job I developed
industrial PMAC servo drives for a leading industrial controls manufacturer
located in Milwaukee. So to solve my servo amplifier problem I have decided
to build my own and have already made significant progress. My homemade
drives will be able to run either DC brush motors or in the future AC
motors. I have a basic torque mode drive in the process of development but
I am thinking I would like the drive to be a velocity mode drive.

My question now is how to interface to LinuxCNC? I really want to connect
all of my I/O using the mesa ethernet cards like the 7I80. From the 7I80 it
looks like there is a way to have SPI interfaces. It seems like the SPI
would be one way to make a simple digital interface to my drives. The 7I80
would send velocity commands and velocity feedback to the drives. The
drives would return status and fault information back to LinuxCNC.

Is it possible for me to use the SPI interfaces with LinuxCNC in the way I
have described? If so, how does one go about setting up the SPI interfaces
and defining what data is passed back and forth? I am hoping Andy Pugh, PCW
or someone that knows can comment.

LinuxCNC  <--Ethernet--> 7I80 -<> I/O inputs and outputs
 |-<> SPI comms to
servo amps  7I46?
 | < encoder inputs for
axis and MPGs

LinuxCNC with position loop only should be able to run with a slower 1mSec
or maybe 500uSec thread and no other high speed thread would be needed. I
may however need to get the velocity feedback to my servo drive at a faster
rate for best/better performance.

My reason for wanting Ethernet is I do not have to have my LinuxCNC PC on
or embedded in my machine, it can be several meters away mounted where it
won't be subject to heat and vibration. In addition with only one
interface, a PC upgrade or repair / swap is easy.


Regards,

John Figie


On Sun, Nov 29, 2020 at 6:47 PM dave engvall  wrote:

>
>
> On 11/27/20 10:52 AM, andy pugh wrote:
> > On Fri, 27 Nov 2020 at 18:45, John Figie  wrote:
> >
> >> I think I am going to attempt to figure out what the parameters of my
> motor
> >> are and make a model to simulate my control loop. For hobby stuff I
> think
> >> LTspice may be good to model and simulate.
> > I am not sure what you hope to gain from a model. The data to populate
> > it would have to come from the actual machine, and at that point you
> > might as well just get on with it.
> >
> IIRC early versions of emc had motor parameters, etc tacked on the the
> end of the parameters for each axis. I don't know if any use was ever
> made of that.
> Maybe some of the early emc-ers with their memory still intact will
> remember as well as a model to insert the data into.
> Dave
>
> Just a comment: I've never had much success using torque mode: that
> doesn't mean I should not go back and revisit it.
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

___
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Re: [Emc-users] Suggestions for a retrofit.

[dave engvall]

On 11/27/20 10:52 AM, andy pugh wrote:

On Fri, 27 Nov 2020 at 18:45, John Figie  wrote:


I think I am going to attempt to figure out what the parameters of my motor
are and make a model to simulate my control loop. For hobby stuff I think
LTspice may be good to model and simulate.

I am not sure what you hope to gain from a model. The data to populate
it would have to come from the actual machine, and at that point you
might as well just get on with it.

IIRC early versions of emc had motor parameters, etc tacked on the the 
end of the parameters for each axis. I don't know if any use was ever 
made of that.
Maybe some of the early emc-ers with their memory still intact will 
remember as well as a model to insert the data into.

Dave

Just a comment: I've never had much success using torque mode: that 
doesn't mean I should not go back and revisit it.



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Re: [Emc-users] Suggestions for a retrofit.

[andy pugh]

On Fri, 27 Nov 2020 at 18:45, John Figie  wrote:

> I think I am going to attempt to figure out what the parameters of my motor
> are and make a model to simulate my control loop. For hobby stuff I think
> LTspice may be good to model and simulate.

I am not sure what you hope to gain from a model. The data to populate
it would have to come from the actual machine, and at that point you
might as well just get on with it.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Suggestions for a retrofit.

[John Figie]

It is good to hear about your experiences with the different ways to
control the motor. I tend to overthink and make things more complicated
than necessary sometimes. But just as a point of clarification, industrial
servo drives typically have 3 loops in cascade for position control. The
inner loop is regulating the current to the motor (which is in an ideal
machine, proportional to the torque). the next loop is a velocity loop and
in the past tachometers were used for feedback. In modern drives, if the
position is sampled fast enough then its derivative can be used for
velocity feedback. Finally there is the position loop. Since my
professional background experience has been with these drives with the 3
cascaded loops, I was going down that path for what I was looking for, but
now since a number of you have said the "torque mode" method work well I
will pursue that route as it is a lot easier for me to do.

I think I am going to attempt to figure out what the parameters of my motor
are and make a model to simulate my control loop. For hobby stuff I think
LTspice may be good to model and simulate. Perhaps in the future I can
update you on the result of my simulation and progress if my retrofit.

Regards,

John Figie


On Wed, Nov 25, 2020 at 11:31 AM Les Newell 
wrote:

> I have used both and personally prefer a single torque loop. My lathe
> runs a 7i80 in torque mode. The router uses velocity mode analog Bosch
> drives with tachos. The mill runs Yaskawa drives that were configured in
> velocity but now I run in torque mode.
>
> It is easier to tune the outer loop in velocity mode however you then
> also need to tune the inner loop (if that isn't already configured in
> the drive). Additionally with velocity mode using analog control you
> nearly always have dither. The machine will hunt between encoder counts.
> With a single torque loop you can configure one encoder count of
> deadband. Once the axis reaches position the motor just stops.
>
> On the mill I originally used velocity mode as that is what it used
> before the retrofit. However the dither drove me mad. In the end I
> switched to torque mode and achieved far lower following errors at speed
> combined with zero dither.
>
> Velocity mode used to be pretty much essential on older controls as they
> did not have a very fast servo loop. LinuxCNC's 1kHz loop is good enough
> to run torque mode for nearly any normal machine.
>
> Les
>
> On 25/11/2020 13:48, Todd Zuercher wrote:
> > I think I'll disagree with Andy a bit on this.  While the minimum
> following error I could achieve with a single torque vs dual loops in
> Linuxcnc was about the same.  The tuning was much easier, and I believe
> that my drives are running much cooler (not working as hard dithering)
> using the dual loops.  It is a bit like comparing balancing a pencil on
> end  on your finger vs a broom handle, the longer one is much easier to
> balance.
> >
> >
>
>
>
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Re: [Emc-users] Suggestions for a retrofit.

[Les Newell]

I have used both and personally prefer a single torque loop. My lathe 
runs a 7i80 in torque mode. The router uses velocity mode analog Bosch 
drives with tachos. The mill runs Yaskawa drives that were configured in 
velocity but now I run in torque mode.


It is easier to tune the outer loop in velocity mode however you then 
also need to tune the inner loop (if that isn't already configured in 
the drive). Additionally with velocity mode using analog control you 
nearly always have dither. The machine will hunt between encoder counts. 
With a single torque loop you can configure one encoder count of 
deadband. Once the axis reaches position the motor just stops.


On the mill I originally used velocity mode as that is what it used 
before the retrofit. However the dither drove me mad. In the end I 
switched to torque mode and achieved far lower following errors at speed 
combined with zero dither.


Velocity mode used to be pretty much essential on older controls as they 
did not have a very fast servo loop. LinuxCNC's 1kHz loop is good enough 
to run torque mode for nearly any normal machine.


Les

On 25/11/2020 13:48, Todd Zuercher wrote:

I think I'll disagree with Andy a bit on this.  While the minimum following 
error I could achieve with a single torque vs dual loops in Linuxcnc was about 
the same.  The tuning was much easier, and I believe that my drives are running 
much cooler (not working as hard dithering) using the dual loops.  It is a bit 
like comparing balancing a pencil on end  on your finger vs a broom handle, the 
longer one is much easier to balance.
  





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Re: [Emc-users] Suggestions for a retrofit.

[Todd Zuercher]

I think I'll disagree with Andy a bit on this.  While the minimum following 
error I could achieve with a single torque vs dual loops in Linuxcnc was about 
the same.  The tuning was much easier, and I believe that my drives are running 
much cooler (not working as hard dithering) using the dual loops.  It is a bit 
like comparing balancing a pencil on end  on your finger vs a broom handle, the 
longer one is much easier to balance. 
 
Todd Zuercher
P. Graham Dunn Inc.
630 Henry Street 
Dalton, Ohio 44618
Phone:  (330)828-2105ext. 2031

-Original Message-
From: andy pugh  
Sent: Wednesday, November 25, 2020 4:20 AM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] Suggestions for a retrofit.

[EXTERNAL EMAIL] Be sure links are safe.

On Wed, 25 Nov 2020 at 04:01, John Figie  wrote:

> I looked over the information you provided. It is not clear to me how 
> the 7i80hv_16_sv..  "SV" sections work. The card provides a PWM output 
> for the 7i40, the encoder feedback comes back to the 7i40 and then 
> back to LinuxCNC servo thread where the loop is closed? So is this 
> then just a single control loop instead of the typical nested Position 
> and Velocity loops that one would have with a velocity mode drive 
> using velocity feedback to the drive and position feedback for LinuxCNCs 
> position loop?

Yes, this is torque-mode operation. If you only have one feedback device per 
axis then you can only have one loop
(Obviously you could use the same feedback device for two loops, but I have a 
feeling that that doesn't add anything. That is a question for the PID 
theorists)

You could, internally to LinuxCNC, set up a velocity loop using motor encoders 
and a position loop using glass scales.

But I have two machines working well enough for my purposes with a single 
torque-mode loop.

--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is designed for 
the especial use of mechanical geniuses, daredevils and lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Suggestions for a retrofit.

[andy pugh]

On Wed, 25 Nov 2020 at 04:01, John Figie  wrote:

> I looked over the information you provided. It is not clear to me how the
> 7i80hv_16_sv..  "SV" sections work. The card provides a PWM output for the
> 7i40, the encoder feedback comes back to the 7i40 and then back to LinuxCNC
> servo thread where the loop is closed? So is this then just a single
> control loop instead of the typical nested Position and Velocity loops that
> one would have with a velocity mode drive using velocity feedback to the
> drive and position feedback for LinuxCNCs position loop?

Yes, this is torque-mode operation. If you only have one feedback
device per axis then you can only have one loop
(Obviously you could use the same feedback device for two loops, but I
have a feeling that that doesn't add anything. That is a question for
the PID theorists)

You could, internally to LinuxCNC, set up a velocity loop using motor
encoders and a position loop using glass scales.

But I have two machines working well enough for my purposes with a
single torque-mode loop.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Suggestions for a retrofit.

[John Figie]

Andy,

I looked over the information you provided. It is not clear to me how the
7i80hv_16_sv..  "SV" sections work. The card provides a PWM output for the
7i40, the encoder feedback comes back to the 7i40 and then back to LinuxCNC
servo thread where the loop is closed? So is this then just a single
control loop instead of the typical nested Position and Velocity loops that
one would have with a velocity mode drive using velocity feedback to the
drive and position feedback for LinuxCNCs position loop?

Regards,

John Figie


On Tue, Nov 24, 2020 at 5:07 PM andy pugh  wrote:

> On Tue, 24 Nov 2020 at 20:25, John Figie  wrote:
>
> > I am thinking that I want to use Mesa Etherent I/O cards and I want to
> use
> > PID servo control.
> >
> > About the motors: These are Peerless DC motors (8 brushes). 66V max and
> > 3.75 Amps Max. 800 RPM coupled directly to the ball screws with a servo
> > coupling.
>
> Mesa have a suitable dual-motor servo drive, the 7i40HV:
>
> http://store.mesanet.com/index.php?route=product/product=83_90_id=147
>
> That pretty-much puts you in the 50-pin-header section of the Mesa
> catalogue, so as the main FPGA card your choices (using Ethernet) are
> 7i93 (headers for two cards) or 7i80HD (headers for 3 cards, and
> available with two different FPGA sizes)
>
> http://store.mesanet.com/index.php?route=product/product=83_85_id=341
>
> http://store.mesanet.com/index.php?route=product/product=83_85_id=62
>
> The 7i40 includes an interface for incremental encoders, so you would
> probably just need to choose a generic IO board such as the 7i37TA to
> complete the system.
> (Or you could go with a 7i44 and a bunch of smart-serial peripherals)
>
> The 7i40 manual is not linked from the product page (something of an
> oversight, PCW) but is here:
> http://www.mesanet.com/pdf/motion/7i40man.pdf
>
> The 7i40 will work with any firmware with "SV" in the bitfile name, so
> despite the fact that it is not mentioned in the 7i40 manual, the
> 7i80HD with the 7i80hd_16_sv12 would be able to drive up to 12 motors
> via 6x7i40 cards.
> In practice you would "turn off" the other potential "SV" sections to
> use the pins as GPIO for the other cards.
>
> It looks like you can probably use the 7i80HD-16 unless you need to
> use a 7i49 card to read resolvers.
> Which begs the question, what was the feedback method used when the
> lathe was new?
>
> Similarly the 7i93 appears to have SV and SVRM (servo/resolver)
> bitfiles available so should work.
>
> --
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> — George Fitch, Atlanta Constitution Newspaper, 1912
>
>
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Re: [Emc-users] Suggestions for a retrofit.

[Gene Heskett]

On Tuesday 24 November 2020 21:15:31 John Figie wrote:

> Andy,
>
> Thanks for the suggestions, I think that is really helpful. I will
> have to look at the docs for this stuff.
>
> As for the lathe it is actually a model 1550 NC even though the swing
> is 14". I have the manual for it and it has a complete parts breakdown
> with illustrations. It looks like the original machine had encoders.
> The spindle encoder is still on the machine and I think it is the
> original  The encoder for the main leadscrew was mounted at the end of
> the screw but it doesn't look like the original.
> The manual also says the "parts shown" are for serial numbers 1550001
> - to ___. Note that I have number 1550003. The way some of the
> limit switches were mounted and wired using conduit fittings seemed
> kind of "home brew" to me, but functional, and when I look at the
> manual it looks like that is really the way this machine was made.
> I am really excited about the thought of getting this machine running.
> Being a 1972 model machine, the tool capability is kind of limited.
> There are only 4 tool positions and it would be difficult to rework
> the tool post to accept some kind of quick change tooling, but I will
> deal with that after I get it running. The DC spindle motor and
> variable speed (mechanical) drive has been replaced with a 5 Hp 3
> phase induction motor. The lathe also has a 3 speed gear box
> incorporated into the headstock.
>
Thats a great candidate to retrofit with a vfd, but I wouldn't change the 
motor just yet, a new technology has recently come down the pike thats a 
bit more efficient AND synchronous. Give it 5 years to wear off the 
luster and then replace it. The new tech promises to be much more 
efficient at the lower speeds.

And Andy is more familiar with Mesa stuff than I'll ever be. His advice 
is good.

> John Figie
>
> On Tue, Nov 24, 2020 at 5:07 PM andy pugh  wrote:
> > On Tue, 24 Nov 2020 at 20:25, John Figie  
wrote:
> > > I am thinking that I want to use Mesa Etherent I/O cards and I
> > > want to
> >
> > use
> >
> > > PID servo control.
> > >
> > > About the motors: These are Peerless DC motors (8 brushes). 66V
> > > max and 3.75 Amps Max. 800 RPM coupled directly to the ball screws
> > > with a servo coupling.
> >
> > Mesa have a suitable dual-motor servo drive, the 7i40HV:
> >
> > http://store.mesanet.com/index.php?route=product/product=83_90;
> >product_id=147
> >
> > That pretty-much puts you in the 50-pin-header section of the Mesa
> > catalogue, so as the main FPGA card your choices (using Ethernet)
> > are 7i93 (headers for two cards) or 7i80HD (headers for 3 cards, and
> > available with two different FPGA sizes)
> >
> > http://store.mesanet.com/index.php?route=product/product=83_85;
> >product_id=341
> >
> > http://store.mesanet.com/index.php?route=product/product=83_85;
> >product_id=62
> >
> > The 7i40 includes an interface for incremental encoders, so you
> > would probably just need to choose a generic IO board such as the
> > 7i37TA to complete the system.
> > (Or you could go with a 7i44 and a bunch of smart-serial
> > peripherals)
> >
> > The 7i40 manual is not linked from the product page (something of an
> > oversight, PCW) but is here:
> > http://www.mesanet.com/pdf/motion/7i40man.pdf
> >
> > The 7i40 will work with any firmware with "SV" in the bitfile name,
> > so despite the fact that it is not mentioned in the 7i40 manual, the
> > 7i80HD with the 7i80hd_16_sv12 would be able to drive up to 12
> > motors via 6x7i40 cards.
> > In practice you would "turn off" the other potential "SV" sections
> > to use the pins as GPIO for the other cards.
> >
> > It looks like you can probably use the 7i80HD-16 unless you need to
> > use a 7i49 card to read resolvers.
> > Which begs the question, what was the feedback method used when the
> > lathe was new?
> >
> > Similarly the 7i93 appears to have SV and SVRM (servo/resolver)
> > bitfiles available so should work.
> >
> > --
> > atp
> > "A motorcycle is a bicycle with a pandemonium attachment and is
> > designed for the especial use of mechanical geniuses, daredevils and
> > lunatics."
> > — George Fitch, Atlanta Constitution Newspaper, 1912
> >
> >
> > ___
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> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
>
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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)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
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Re: [Emc-users] Suggestions for a retrofit.

[John Figie]

Andy,

Thanks for the suggestions, I think that is really helpful. I will have to
look at the docs for this stuff.

As for the lathe it is actually a model 1550 NC even though the swing is
14". I have the manual for it and it has a complete parts breakdown with
illustrations. It looks like the original machine had encoders. The spindle
encoder is still on the machine and I think it is the original  The encoder
for the main leadscrew was mounted at the end of the screw but it doesn't
look like the original.
The manual also says the "parts shown" are for serial numbers 1550001 - to
___. Note that I have number 1550003. The way some of the limit
switches were mounted and wired using conduit fittings seemed kind of "home
brew" to me, but functional, and when I look at the manual it looks
like that is really the way this machine was made.
I am really excited about the thought of getting this machine running.
Being a 1972 model machine, the tool capability is kind of limited. There
are only 4 tool positions and it would be difficult to rework the tool post
to accept some kind of quick change tooling, but I will deal with that
after I get it running. The DC spindle motor and variable speed
(mechanical) drive has been replaced with a 5 Hp 3 phase induction motor.
The lathe also has a 3 speed gear box incorporated into the headstock.

John Figie


On Tue, Nov 24, 2020 at 5:07 PM andy pugh  wrote:

> On Tue, 24 Nov 2020 at 20:25, John Figie  wrote:
>
> > I am thinking that I want to use Mesa Etherent I/O cards and I want to
> use
> > PID servo control.
> >
> > About the motors: These are Peerless DC motors (8 brushes). 66V max and
> > 3.75 Amps Max. 800 RPM coupled directly to the ball screws with a servo
> > coupling.
>
> Mesa have a suitable dual-motor servo drive, the 7i40HV:
>
> http://store.mesanet.com/index.php?route=product/product=83_90_id=147
>
> That pretty-much puts you in the 50-pin-header section of the Mesa
> catalogue, so as the main FPGA card your choices (using Ethernet) are
> 7i93 (headers for two cards) or 7i80HD (headers for 3 cards, and
> available with two different FPGA sizes)
>
> http://store.mesanet.com/index.php?route=product/product=83_85_id=341
>
> http://store.mesanet.com/index.php?route=product/product=83_85_id=62
>
> The 7i40 includes an interface for incremental encoders, so you would
> probably just need to choose a generic IO board such as the 7i37TA to
> complete the system.
> (Or you could go with a 7i44 and a bunch of smart-serial peripherals)
>
> The 7i40 manual is not linked from the product page (something of an
> oversight, PCW) but is here:
> http://www.mesanet.com/pdf/motion/7i40man.pdf
>
> The 7i40 will work with any firmware with "SV" in the bitfile name, so
> despite the fact that it is not mentioned in the 7i40 manual, the
> 7i80HD with the 7i80hd_16_sv12 would be able to drive up to 12 motors
> via 6x7i40 cards.
> In practice you would "turn off" the other potential "SV" sections to
> use the pins as GPIO for the other cards.
>
> It looks like you can probably use the 7i80HD-16 unless you need to
> use a 7i49 card to read resolvers.
> Which begs the question, what was the feedback method used when the
> lathe was new?
>
> Similarly the 7i93 appears to have SV and SVRM (servo/resolver)
> bitfiles available so should work.
>
> --
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> — George Fitch, Atlanta Constitution Newspaper, 1912
>
>
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Re: [Emc-users] Suggestions for a retrofit.

[Gene Heskett]

On Tuesday 24 November 2020 15:09:42 John Figie wrote:

> emc-users,
>
> I acquired a Clausing 1450 NC lathe with the intention of LinuxCNC
> retrofit about 6 years ago. I had all kinds of plans to make my own
> servo drives but never really made much progress due to other
> priorities. Now I am getting impatient and want to move forward.
> Currently this machine has no controls. The machine is fitted with x
> and z servo motors without tachometers and with no provisions for
> tachs. The original control was NC by paper tape. I have none of the
> original controls and I am apparently the 3rd owner intending to
> retrofit this machine. The basic machine is early 70's vintage and
> looks like an engine lathe. It is in remarkably good shape probably
> because it is not a production style machine and it was probably a
> real pain to program and run. The ball screws show no lost motion with
> a 0.0001" reading indicator. The ways look good and are flame
> hardened. The serial number is 155003 stamped on the bed.
>
> My plan:
> I have an Asus M5A 78L-M LX MB with debian 10 and preempt-rt kernel. I
> have LinuxCNC 2.8 installed. I also have installed an intel dual port
> server NIC that is supported by the OS.
> Max latency is 50,000 nsec average is about 25,000 nsec. with the
> combination above.
>
> I am thinking that I want to use Mesa Etherent I/O cards and I want to
> use PID servo control.
>
> About the motors: These are Peerless DC motors (8 brushes). 66V max
> and 3.75 Amps Max. 800 RPM coupled directly to the ball screws with a
> servo coupling.
>
> I will need to fit decent encoders to the ball screws. I have some
> SICK hiperface SIN/COS encoders with 1024 cycles per rev. Even if I
> just use these as incremental encoders without SIN/COS interpolations
> I can get 4096 counts / rev and my ball screws are 0.2" / Rev so that
> would yield 0.48828" of linear travel per count.  Max speed will
> be 160 in/min @ 800 RPM.
>
> I am wondering what might be the easiest way to drive these motors and
> get reasonable performance without spending too much money.

That last drops a pipe wrench in the gears, but here is what I would do.

Pick a Mesa card that can supply 2 pwmgen modules, one for each axis that 
count=2 because with LCNC you don't need a springy compound under your 
toolpost, a block of cast iron sitting on the carriage, milled to the 
same height as the compound was will be many time more rigid and 
chatter-free. If this board has a spare pci socket, the Mesa 5i25 is a 
good candidate. You won't need the ethernet to run your machine. And the 
latency will be better I expect.

Omron sells A/B/Z encoders for about $20/axis if what you have doesn't 
work. Up to 2048 per rev, that is 8192 edges per turn. Up to 6000 revs, 
so your 800 is a piece of cake.

For motor drivers, the Pico Systems pwm-servo amplifier is a bit of 
overkill but is as bulletproof as they come. The only problem is that it 
needs a 12 volt signal and a tickle from a boot module to enable it. You 
may be able to find something smaller than its 160 volt, 20 amp maximum 
ratings. It is a full 4 quadrant controller, feeding the motors energy 
back into the power supply while stopping to reverse. But then it will 
use that energy to re-accelerate the motor in the other direction.

But... Its around $120/copy. I actually use 2 of them, driving 1hp PMDC 
motors to around 2hp actual output as spindle drivers. Neither motor has 
complained in several years, but one of them has totalled the belt drive 
in a 7x12 lathe 6 or 7 times.  That's how fast they can respond.

I am in the process of motorizing a Chinese clone of a BS-1, and am using 
an estate gate motor rated at 100 watts at 24 volts, and have after 
quite a few false starts, finally found a dual H-Bridge driver with a 
pair of Infineon BTS 7960 chips on it, rated at 43 amps, but the max 
voltage is also 45 volts, below what your motors need for good 
performance.

Running this motor from a 350 watt switcher putting out 24 volts, running 
overnight, the motor was not anywhere near too warm the next day, and 
this $13 driver was dead cold at room temp after about a 12 hour run. I 
have a higher voltage supply, a 42.5 volt, but haven't tried it yet.

This driver needs the PWMGEN to be run in mode-2. This will be a common 
requirement for most of the H-Bridges out there.  The problem is that 
most are designed to be used in cars for such as seat controls but will 
suffer destructive shoot thru at the higher voltages.  So look around. 
Your 66 volt motors can probably take twice that for the few seconds 
they run to null the PID without damage unless the shaft twists in the 
coupling. They will make serious torque running that way. One of the 
reasons I like the Pico amplifier is that you can program the maximum 
current it will allow to reach the motor, thereby controlling the over 
torque. You'll hear the iron in the motor squeak when that happens.

> This is not my first LinuxCNC 

Re: [Emc-users] Suggestions for a retrofit.

[andy pugh]

On Tue, 24 Nov 2020 at 20:25, John Figie  wrote:

> I am thinking that I want to use Mesa Etherent I/O cards and I want to use
> PID servo control.
>
> About the motors: These are Peerless DC motors (8 brushes). 66V max and
> 3.75 Amps Max. 800 RPM coupled directly to the ball screws with a servo
> coupling.

Mesa have a suitable dual-motor servo drive, the 7i40HV:
http://store.mesanet.com/index.php?route=product/product=83_90_id=147

That pretty-much puts you in the 50-pin-header section of the Mesa
catalogue, so as the main FPGA card your choices (using Ethernet) are
7i93 (headers for two cards) or 7i80HD (headers for 3 cards, and
available with two different FPGA sizes)
http://store.mesanet.com/index.php?route=product/product=83_85_id=341
http://store.mesanet.com/index.php?route=product/product=83_85_id=62

The 7i40 includes an interface for incremental encoders, so you would
probably just need to choose a generic IO board such as the 7i37TA to
complete the system.
(Or you could go with a 7i44 and a bunch of smart-serial peripherals)

The 7i40 manual is not linked from the product page (something of an
oversight, PCW) but is here:
http://www.mesanet.com/pdf/motion/7i40man.pdf

The 7i40 will work with any firmware with "SV" in the bitfile name, so
despite the fact that it is not mentioned in the 7i40 manual, the
7i80HD with the 7i80hd_16_sv12 would be able to drive up to 12 motors
via 6x7i40 cards.
In practice you would "turn off" the other potential "SV" sections to
use the pins as GPIO for the other cards.

It looks like you can probably use the 7i80HD-16 unless you need to
use a 7i49 card to read resolvers.
Which begs the question, what was the feedback method used when the
lathe was new?

Similarly the 7i93 appears to have SV and SVRM (servo/resolver)
bitfiles available so should work.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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