Comments on: Coming firmware changes & Sanyo Denki P5 example

By: Tero

Tero — Thu, 31 Oct 2013 10:46:54 +0000

It is correct that only velocity information is required from the inner loop. Without it any backlash or flex of the mechanics would render system unstable – or very allow only very sluggish tuning.

By: TonyT

TonyT — Mon, 28 Oct 2013 19:08:38 +0000

Typically with dual loop feedback, the encoders are used for different purposes, such as:
–rotary encoder is used for velocity feedback
–linear encoder is used for position feedback

I’ve used a dual loop setup twice, one with a MEI board and once with a Galil 18xx (that was a fun system, it had air bearings, flexures, and a granite table).

By: Tero

Tero — Fri, 18 Oct 2013 12:52:28 +0000

It should be possible to connect SinCos and digital encoder to J1 connector simultanously (at least it’s designed to allow that), not yet tested though.

Second way would be to put digital encoder to J5 connector but that would replace step/dir input that many people need.

By: Tero

Tero — Fri, 18 Oct 2013 12:50:12 +0000

Dual-loop feedback allows one to use two feedback device on single axis. It won’t enable new possibilities but enhances system accuracy because lead screw backlash, pitch error and flex can be automatically compensated on the fly.

By: Weerasak

Weerasak — Fri, 18 Oct 2013 02:50:03 +0000

Good to hear, you are planing to do dual-loop feedback in Argon. I found this feature in Dynomotion Kflop controller but don’t know much about it.

I can only imagine that it can be used in taping and drilling application only when x, y axis position are corrected at outer loop then z move down.

Can it be used in 3d milling also?

By: Johann

Johann — Wed, 16 Oct 2013 19:58:04 +0000

no I’m not talking about TTL output from argon for feedback value encoder

I would compose my dual loop encoder feedback with 1 TTL (quadrature) and 1 SIN / COS encoder (1 Vp-p)
it’s possible?

By: Tero

Tero — Wed, 16 Oct 2013 16:44:42 +0000

Dual-loop feedback support is in the plans and designed in the hardware already. However there are many FW things to do before it.

Do you mean TTL encoder output? No encoder outputs are in the hardware.

By: Johann

Johann — Wed, 16 Oct 2013 11:31:04 +0000

hi Tero
a question about the future possibility of argon
I have a machine configuration that allow myself to have two encoder feedback for axis
1 linear encoder 1 and rotary encoder
it can be used to eliminate the problems of backlash in the endless screw

in a future firmware would it be possible to have encoder feedback COS / SIN and return TTL simultaneously?

thank you