DDSCV1.1 3 and 4 axis offline motion controller

[Merlin201314]

I would call this "customization", as i have no words to describe the original boot screen!!!
But i'm working on a very good graphic, so it will make sense then. This was just a trial.
A big thank to Benedikt for his contribution about the firmware, we hope to make this one "open source" soon.

[Lee Roberts]

I would call this "customization", as i have no words to describe the original boot screen!!!
But i'm working on a very good graphic, so it will make sense then. This was just a trial.
A big thank to Benedikt for his contribution about the firmware, we hope to make this one "open source" soon.

Yeah great work you two are doing on this, I read the mad modder thread on it last night.

I wonder if Boyan has seen it yet ?

[Merlin201314]

Yeah great work you two are doing on this, I read the mad modder thread on it last night.

I wonder if Boyan has seen it yet ?

Mmmhhh, don't know , maybe not yet, in the meantime this is the better one, Benedict is going to include the design as default if possible, let's see how is going on in the next few days...
Cheers 🍻

Sended by my tapatalk

[Boyan Silyavski]

The modding this controller needs is the following:

-make A to be slaved to Y / i still dont know if that is not originally done as there is a place where you say if A is B, whatever that means even if degrees does not change to mm/
-make the squaring of gantry YA

-read the M06 command

-reassign the Limit switches inputs for other purposes . This controller only needs 4 home inputs, not 12. Connecting the limits together on each axis , like is normally done by DIYers



Who is Benedict?

[Merlin201314]

The A axis slave reference can be set as A/X, A/Y, A/Z in my controller,

A or B axis selection is not clear in the software, but at this point everything is possible with the chinese.......
"circ" should mean mm in translation, as the circumference is measured in mm, not in degree,(rotation=degree)
Benedikt is the Mistery man :-)

[Boyan Silyavski]

I discovered that i have a problem with small carvings and very fine details. I tried 2 times to carve a stamp from aluminum ~30mm diameter, X and Y started slowly to loose position. Lowered the acceleration from 3000 to 1000, did a dry run also.

Same problem persists. .


Now the question is: the controller??? or the servos need further tuning??? or i have to slow further things down, which i dont believe is the case. I remember i bumped up servos quite much to be responsive via software and even 3000 accelerations and more than 10000 mm/m speeds on objects like 200x200cm there was no problem at all. Checked initially the machine, does not seem to have sth loose.


Any ideas??? Could that be the small lines? Exported v carving file as arcs also, same again. Thinking about it it looses both X and Y and moves slowly in diagonal on every step down of the Z is visible. At the end of tool path controller shows same machine coordinates as on start 0.

Should i try to find the look ahead in the controller and make it bigger, i was thinking of disabling drawing the tool paths?


i don know what exactly to do now except bump more the servo response and see what happens

[JAZZCNC]

Now the question is: the controller??? or the servos need further tuning???

If there is option to change Step edge ie: Active hi/lo then try this. You could be on the wrong side of the edge in which case you'll lose 1 pulse for every direction change.?

[Merlin201314]

In the controller, in the last part of the machine parameter you can fond the "interpolation period", set it up at 0,005 and try it, change even the "screen refresh" at not less than 4000, otherwise the screen will slow the cpu, as it not equipped with a graphic card.(you don't need to watch the screen, watch the machine).

Find even the "operating acceleration" parameter and set it up at 500mm is the diagonal interpolated acceleration try it and find a reasonable one for your machine.
Is just a bit of thing to try, maybe it won't help you, but it worth try.....

If you have servos, they are coming with resolver on the back, so your motors know exactly where and when they are at all time.
So, even with strong acceleration they shouldn't loose position... Here the problem: is your Router ridgid enough? Because with long traveling and strong accelerations the structure has the time to stabilize in between the movment, with very short traveling the machine is going into a factor called "structural resonance" and "inverted motion", what that mean? It mean that the axis is called to travel in a direction, but due to acceleration and mass involved the underneath structure is going in the opposite direction, and in a very small piece this factor is noticeable, even more when you are carving aluminium rather than wood, thats why the milling machines are heavy, especially CNC centers. Another thing to check is the connections between the motors and the ballscrews.... check all the mechanic parts first, as per very small pieces and high acceleration you are going to join another world with a high inversion rate, is called "jerk"
A router is a router, and as much as you like it, is shaking and flexible under high torque.....
I would suggest you to lower the acceleration to 300/500mm Min and look if the problem is persistent before retuning all the motors and blame them or the controller.

Regards

[Boyan Silyavski]

If there is option to change Step edge ie: Active hi/lo then try this. You could be on the wrong side of the edge in which case you'll lose 1 pulse for every direction change.?

I always forget about that one, but as far as i remember was correctly set to work with normal BOB. I will now check again. In controller could not find a way to change that. I know where to change that in the servos. Will have to read the manual again though.

PS. alright, there is that in the controller, i found it. will try it later

In the controller, in the last part of the machine parameter you can fond the "interpolation period", set it up at 0,005 and try it, change even the "screen refresh" at not less than 4000, otherwise the screen will slow the cpu, as it not equipped with a graphic card.(you don't need to watch the screen, watch the machine).

Find even the "operating acceleration" parameter and set it up at 500mm is the diagonal interpolated acceleration try it and find a reasonable one for your machine.
Is just a bit of thing to try, maybe it won't help you, but it worth try.....

If you have servos, they are coming with resolver on the back, so your motors know exactly where and when they are at all time.
So, even with strong acceleration they shouldn't loose position... Here the problem: is your Router ridgid enough? Because with long traveling and strong accelerations the structure has the time to stabilize in between the movment, with very short traveling the machine is going into a factor called "structural resonance" and "inverted motion", what that mean? It mean that the axis is called to travel in a direction, but due to acceleration and mass involved the underneath structure is going in the opposite direction, and in a very small piece this factor is noticeable, even more when you are carving aluminium rather than wood, thats why the milling machines are heavy, especially CNC centers. Another thing to check is the connections between the motors and the ballscrews.... check all the mechanic parts first, as per very small pieces and high acceleration you are going to join another world with a high inversion rate, is called "jerk"
A router is a router, and as much as you like it, is shaking and flexible under high torque.....
I would suggest you to lower the acceleration to 300/500mm Min and look if the problem is persistent before retuning all the motors and blame them or the controller.

Regards

Machine is quite rigid, servos are more or less quite accurately calculated, so actually they are not over sized for the machine but exactly sized. I had some under and overshooting before, but i raised quite much the snappiness of it all.

I started now changing things here. I did that just before reading what you said, but more or less i deducted the same. I lowered panel response time to 1000, raised read lines / not shown here in manual/ to max 3600. Which i assume is the read ahead? and lowered interpolation time to 0.002 , which should give much tighter corners or will lower mechanical resolution? its not clear what they want to say. Just testing it now. If not ok 0.002 i will raise it to 0.01 to see what happens

[Boyan Silyavski]

Ok. The changes did not work so i reset all back to normal. after all if the controller is capable of 400kz per axis i dont see what the problem could be from secondary details like display and so on.


First i took a look at my drive and motor timing specs and compared with the timing of the controller. Results that this controller is really high spec and the servos must not have any problem with the default setting:




So far so good. I include the above line of thoughts just for the sake if somebody needs to understand whats happening with his setup.

Again back to what Dean said, about the pulse. looking at the table below it seemed i should not have had a problem as both in the controller and drives was set to high / step pulse/ . Changed the controller pulse to low and now its working fine. Thanks Dean!





Though i still not get why on controller Z is set differently than X and Y as default? No i have to think of a way to check the correctness of Z . Problem seems to be as till now i had done files where Z has no more than 5 steps, so may be thats why i had not seen the problem. I dont know if it counts that the CAM makes the Z oscillate on the toolpath, i think that counts a a change, so it seems better not touch anything for now.