Upgrading form Acorn to AcornSix for Closed loop axis

[Hjavaher]

Hi,
I just ordered all the necessary components to upgrade my CNC from Acorn to AcornSix. I wanted to do this in order to utilize glass scales for positional feedback on the X, Y and Z axis. I can't find anything in the AcornSix documentation for the hookup, configuration or requirements of the glass scales. Can anyone help me point me to the right direction with documentations?

Glass encoders I'm about to buy are from Ebay: https://www.ebay.com/itm/125442589098?var=426464455652
Are these any good? Should I find Absolute or relative encoders?
The seller has 1um and 0.1um resolution, is there any downside to getting the 0.1um resolution?

Thank you,
Hiva

[centroid467]

Hello Hiva,

You will need scales that have the differential line driver (RS422 style) outputs.

That listing is a little unclear as to what output type they have. It first states that the 0.1um resolution version has RS422 drivers while the 1.0um version has single ended TTL outputs. Then immediately afterwards it says that only TTL is available.


We done some internal testing with Aikron AKS series scales (which can be found here) and other users have had success with them. You will need to select the RS422 output option.
https://www.centroidcnc.com/centroid_di ... erm=S15235

[suntravel]

Ditron and Aikron are both ok if you get them with RS422 output.

DB9 Pinout must be changed to the Centroid layout.

I would only buy directly from the factory, not from resellers to make sure they are RS422 and to have factory support.

Uwe

[Hjavaher]

Thank you both, I literally know nothing about scales so this is immensely helpful.

Any input on absolute vs incremental? Also any downside of buying the highest resolution one I can find?

Lastly, my system is imperial, should I stick to a scale that is also imperial or it doesn’t matter?

Thank you!

[centroid467]

Imperial vs metric will not matter although I am guessing it will be much easier to find metric scales. You would have to do a little bit of math when setting the graduations/inch in CNC12.

I don't see any reason to use absolute scales over incremental here. I think your wallet will thank you as well.

[andrkorb]

scale TTL with converter TTL to RS422 will be working with AcornSix?

[suntravel]

scale TTL with converter TTL to RS422 will be working with AcornSix?

Acorn 6 needs clean RS422 signals if converted or not....

... if the converter is fast enough it will be ok.

For a clean fast and chatter free closed loop timing is very important.

Uwe

[Hjavaher]

Hi, as suntravel suggested, I’m ordering either Ditron and Aikron scales.

Couple of other questions:

1) documentations: any wiring/configuration documentations out there yet for this?

2) to get started quickly with can I import my setting from acorn to acornsix as a baseline or do I need to start from scratch?

[suntravel]

Pinout is documented with the scales and for the encoder inputs in the Acorn Six manual / all schematics.

Printout the Wizard settings, start from scratch with typing the settings from Acorn Wizard.

Uwe

[Hjavaher]

My lazy side was hoping I could import my settings. My logical side knew my lazy side was wrong but worked hard staying in denial

thank you SunTravel!