Linear scale in OpenPnP

[svetozar161]

Greetings. Does anyone have any experience using such encoders and how to connect them in Openpnp? What kind of controller is needed? I need accuracy to install 0402 components. Thank you.

[tonyl...@gmail.com]

I haven't used anything like that, but they wouldn't connect to OpenPnP. You would connect them to your motion controller/motor drivers to form a closed loop servo system.

[Michael Anton]

You don't need the accuracy of those scales for 0402 parts.  My belt driven machine that uses servomotors does 0402 just fine with just the encoders on the motors.  0402 parts can be placed quite a long way off, and still center themselves on the pads nicely during reflow.

If you wanted to use scales like that, you would need to find a motor controller that supports them as an input.  Generally they can't be used to directly control the motor, but can be used as an outside feedback loop to get the motors to the final desired position.  As in if you were using a servo motor, you would still need rotary encoders on the motors to close the servo loop, and the linear encoder would be a secondary feedback loop, but not used to deal with the motor dynamics.

Mike

[JW]

Agreed, my machine uses closed loop stepper motors and ballscrews, and I've placed 0201 no problem at all, including 0402 without using vision.

Why do you think you need such devices, what issue are you having placing 0402 now?

[Tony Huynh]

In my opinion, you use linear slide and GT2 belt drive, along with Step motor or Hybrid Servo then still meet the size 0402 well. I am using machine with Nema23 Step motor working well. Accuracy it is related to many factors

Vào lúc 19:18:34 UTC+7 ngày Thứ Ba, 13 tháng 5, 2025, sveto...@gmail.com đã viết: