Attachments :

So, as you can see on the picture I have attached, I am driving my gantry system with a linear actuator at only one side. I chose very beefy linear rails to counteract the results of the uneven driving. After all, normal lathes also only have a lead screw on one side...

Anyway, I have a glass scale mounted to the other side of the gantry. The ultimate goal for this is to remove the variation in the ball screw and thermal expansion, but right now, I would like to use it to see if there is any backlash or twisting in my setup.

What I would like is an extra trace in the step response screen to show not only the position as given by the encoder but also the position as given by the glass scale. So a graph with commanded position, position as given by shaft encoder, position as given by glass scale.

I realize that I am unlikely to get that in the actual step response screen, but is the best way to achieve what I want by other means?

Thanks for taking the time to read this.

Jan

Hi Jan,

Besides capturing data to a file as SJH describes with a C Program such as:  CaptureXYMotionPosDest.c

There is also the Extended Logging C# program contributed by Greg in the latest Test Releases.  It takes a bit to learn to use but is extremely powerful.  It is based on console logging so it can't sample as fast as a C Program to memory but should be plenty fast enough for your purposes.  Run ExtendedLoggingKflop.exe.  Change the C Program to log the data of interest to the Console and the other C Program to move in your desired manner.  Then configure what and how you want the plots to look.  There is also a brief manual called  Readme.md (can be opened with WordPad)

See the video:

https://youtu.be/BisZrkeGMLM

Regards
TK

 

You could write a C program to sample and save the data you need in the gather buffer.  That program could also provide the motion stimulus commands.  After the run was finished, another program could run which would convert the data in the gather buffer into a CSV format and write it to a file on the PC.  You then graph the spreadsheet data using Excel etc.

For what you are trying to do, the data you need to save would be the chan[n].Dest field (for position target), then chan[n].Position for the encoder reading, and another channel's Position for the glass scale reading.  Maybe you could subtract one Position from the other (after appropriate scaling), since you are only interested in the error between rotary and linear encoders.

Regards,

SJH

On Mon, Dec 11, 2017 at 4:13 PM, homeloan@... [DynoMotion] <DynoMotion@yahoogroups.com> wrote:

 

So, as you can see on the picture I have attached, I am driving my gantry system with a linear actuator at only one side. I chose very beefy linear rails to counteract the results of the uneven driving. After all, normal lathes also only have a lead screw on one side...

Anyway, I have a glass scale mounted to the other side of the gantry. The ultimate goal for this is to remove the variation in the ball screw and thermal expansion, but right now, I would like to use it to see if there is any backlash or twisting in my setup.

What I would like is an extra trace in the step response screen to show not only the position as given by the encoder but also the position as given by the glass scale. So a graph with commanded position, position as given by shaft encoder, position as given by glass scale.

I realize that I am unlikely to get that in the actual step response screen, but is the best way to achieve what I want by other means?

Thanks for taking the time to read this.

Jan

Attachments :

Hi Jan,

Actually the Extended logging Readme.md doesn't open well with WordPad.  Attached is a pdf file.  Or view it on Greg's Gethub page:

https://gitlab.com/Greg9504/ExtendedLoggingKflop

Regards
TK

 

Hi Jan,

Besides capturing data to a file as SJH describes with a C Program such as:  CaptureXYMotionPosDest.c

There is also the Extended Logging C# program contributed by Greg in the latest Test Releases.  It takes a bit to learn to use but is extremely powerful.  It is based on console logging so it can't sample as fast as a C Program to memory but should be plenty fast enough for your purposes.  Run ExtendedLoggingKflop.exe.  Change the C Program to log the data of interest to the Console and the other C Program to move in your desired manner.  Then configure what and how you want the plots to look.  There is also a brief manual called  Readme.md (can be opened with WordPad)

See the video:

https://youtu.be/BisZrkeGMLM

Regards
TK

On 12/11/2017 4:57 PM, Hardy Family hardy.woodland.cypress@... [DynoMotion] wrote:

 

You could write a C program to sample and save the data you need in the gather buffer.  That program could also provide the motion stimulus commands.  After the run was finished, another program could run which would convert the data in the gather buffer into a CSV format and write it to a file on the PC.  You then graph the spreadsheet data using Excel etc.

For what you are trying to do, the data you need to save would be the chan[n].Dest field (for position target), then chan[n].Position for the encoder reading, and another channel's Position for the glass scale reading.  Maybe you could subtract one Position from the other (after appropriate scaling), since you are only interested in the error between rotary and linear encoders.

Regards,

SJH

On Mon, Dec 11, 2017 at 4:13 PM, homeloan@... [DynoMotion] <DynoMotion@yahoogroups.com> wrote:

 

So, as you can see on the picture I have attached, I am driving my gantry system with a linear actuator at only one side. I chose very beefy linear rails to counteract the results of the uneven driving. After all, normal lathes also only have a lead screw on one side...

Anyway, I have a glass scale mounted to the other side of the gantry. The ultimate goal for this is to remove the variation in the ball screw and thermal expansion, but right now, I would like to use it to see if there is any backlash or twisting in my setup.

What I would like is an extra trace in the step response screen to show not only the position as given by the encoder but also the position as given by the glass scale. So a graph with commanded position, position as given by shaft encoder, position as given by glass scale.

I realize that I am unlikely to get that in the actual step response screen, but is the best way to achieve what I want by other means?

Thanks for taking the time to read this.

Jan

Thanks for the help.
I just tried to download the zip file with the binary as referenced in Greg's page. However, Dropbox says the file does not exist. Does anyone here have the zip file on hand?

Jan

Hi Jan,