Converting CHMT-36VA to Duet 3 6HC control

[Jarosław Karwik]

Hi,

I have been converting my machine  CHMT-36VA to Duet 3 6HC  - after I removed original controller. I have planned to use my own, but due to selling the machine  I decided to go for widely known generic control.

There is one source of information:

https://github.com/openpnp/openpnp/wiki/Duet3D-Openpnp-Example

But:

- Was it really done ? There are issues with the info as the machine is 6 axis - not as claimed 5 ( the missing one is driver for tape peelers wheels)

- Has anyone else used Duet for the conversion ? I will use I&S from OpenPnp, but any details specific for the machine are welcomed.  E.g.  driver current for X/Y/peel axes

 

[Jarosław Karwik]

Just got Duet.

Under the hood - ready for conversion.

Few findings:

1)  Original stepper supply was 36V - it is too much for Duet 6HC ( 32V limit in my revision). I will replace all these supplies ( there is 36V, 12/24V and 24V) with single bigger 24V supply.

With Duet you would need two extra expansion boards with drivers ( which can take 48V as well as encoders)

2) Some connectors ( for motors ) fit directly :-)

[SM]

>> 32V limit in my revision

it's a pity, because many small stepper motors are really fun at 36V and above :-)

[Wayne Black]

Yes, it was really done by me. I'm pretty sure others have done it as well. Peelers are treated as "Actuators" not "Axis". My conversion was a full gut. I replaced the head, swapped the pumps for vacuum ejectors and replaced the closed loop drivers w 48V units. I may throw some unused 72V CP motors on from another project. Don't have a lot more info on it as I'm a bad note taker, but here's some pics I took at the time of doing it;

https://drive.google.com/file/d/1nADTjQqW7TY2nEyGHLEbWhwVE-ORh23l/view?usp=drive_link

https://drive.google.com/file/d/1oZ4uuAEK81fCmsdIu-k0E7GHzi31tkfS/view?usp=drive_link

 https://drive.google.com/file/d/1oYH8oRu-LzYoIieFKMq-fTUFuHrf0_Rl/view?usp=drive_link

 https://drive.google.com/file/d/1oV5Q19JJOTL2bOR_XflFGQkWjMNljSiP/view?usp=drive_link

On Friday, July 19, 2024 at 1:03:01 PM UTC-7 Wayne Black wrote:

Yes, it was really done by myself. I'm pretty sure others have done it as well. Peelers are treated as "Actuators" not "Axis". My conversion was a full gut. I replaced the head, swapped the pumps for vacuum ejectors and replaced the closed loop drivers w 48V units. I may throw some unused 72V CP motors on from another project. Don't have a lot more info on it as Im a bad nto taker, but here's some pics I took at the time of doing it;

https://drive.google.com/file/d/1nADTjQqW7TY2nEyGHLEbWhwVE-ORh23l/view?usp=drive_link, https://drive.google.com/file/d/1oZ4uuAEK81fCmsdIu-k0E7GHzi31tkfS/view?usp=drive_link, https://drive.google.com/file/d/1oYH8oRu-LzYoIieFKMq-fTUFuHrf0_Rl/view?usp=drive_link, https://drive.google.com/file/d/1oV5Q19JJOTL2bOR_XflFGQkWjMNljSiP/view?usp=drive_link

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Wayne Black

Owner

Black Box Embedded, LLC

black...@blackboxembedded.com

1.831.682.4964

[Jarosław Karwik]

Hi,

@Wayne, these pictures are behind protected access :-(

And you are right - peelers need to be configured as actuators ( with scripting)

Do you remember what current do you use on X/Y ?  There are two different motor sizes, unfortunately no type designations.

About 24V setup:

- I will just start with standard Duet. Original Chinese setup could not place reliably with 100%  speed ( vibrations) , I was using like 50%.

- If the 24V is really limitation - I will add two Duet 1HCL modules with 48V supply ( as this is needed only on X/Y). This is very easy, although gets a bit expensive.

I will test

[Wayne Black]

sorry, heres the pics. Probably not that helpful, but I know people want pics or dont think it happened. Anyrate, machine works fine but is currently been torn apart for the new head.

To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/b255b5c6-e99c-4344-b0a6-6ae464460c15n%40googlegroups.com.

[Jarosław Karwik]

Wow, you made a beast !!! And likely  very noisy with these ejectors....

[Wayne Black]

On the contrary it is much quieter than the original pump set up. Not to mention much faster pick ups and releases. 

To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/52eccc52-f0e7-42fb-a7f7-449f499813a7n%40googlegroups.com.

[Jarosław Karwik]

Small investigation:

- It uses SX7236M  old and simple stepper driver    https://www.semicon.sanken-ele.co.jp/sk_content/sx7232m_sx7236m_ds_jp.pdf

- I have checked reference voltages and sense resistors and got following peak current ( Itrip):

   X/Y/Peeler  - 1.4A

   Z - 0.46A

   U/V - 0.39A

The X/P motors are NEMA23 ( 56x56x77mm), Y is a bit smaller NEMA23 ( 56x56x52)

[vespaman]

Thanks for sharing the current limit setup! 

This is useful for any driver upgrades (I have been thinking about upgrading for about a year, but still haven't - machine is working good, but I think a more modern driver would yield some extra speed, esp if going for higher voltages, like Wayne has. Also reduction of heat..

- Micael