Best Mesa Cards/ Combo for DELTA ASD-A2 drive/motor

With step and direction position control, you do NOT need to connect the encoder to the mesa card. The control is telling the motor to got x many steps, like with a stepper motor, and "assumes" the motor went the correct distance without checking.

With analogue speed or torque control, you need to connect the encoder PASS THROUGH from the drive to the mesa board. The encoder from the MOTOR still goes to the drive. The drive then outputs an emulated quadrature signal that the mesa can read. the control is only giving the servo a speed, and therefore needs to read the encoder to know where it is and to then give it a new speed.

Ideally, you'd want the control to close the loop and always know where the motor is - this is how siemens, fanuc etc do it, but linuxcnc is easier to use with plain step and direction and not all drives (like my sanyo) play happily with it.

Linear scales a re separate additional system - a secondary encoder that the control can read in addition or instead of the motors encoder.

On the 20 bit vs 23 bit... the new delta B3 drives and motors are 24 bit, and cheaper. That's what im using.

The Bit depth isn't very relevant directly - your machine wont be more precise for it. What it does is allow the drive to respond with much higher dynamics and inertia handling - simply because it can scan the encoder for movement much faster. The delta B3 for example has a 3khz velocity loop, vs 1khz on the A2, and 500hz on the B2 (and 100hz on my 1990 sanyo drives that I couldn't tune). Many of the low cost Chinese 'brand" drives are in the 200-500hz range. as a result, they wont have the dynamics ability of the delta B3 or A2. If your machine isn't going to accelerate fast, it's not a big deal, buy what's cheapest with the right power. If you want 0.5G acceleration and 2000ipm, then the B3 will be better than the A2, and the A2 better than the B2 by a noticeable margin.

Like tommy though, you lost me at 4080 extrusion, I don't know what your design is, but that extrusion is what you get on a $299 mini tabletop router frame.

Thanks ihavenofish and Toommy.

Don't worry about the 4080 extrusions I have many of those to connect together. I will use resin inside of them or fill it with sand or cement. It will get sturdy. Otherwise, I will use my rusty welding skill and build a new frame out of steel tubes.

Just for clarification. When you said, "you need to connect the encoder PASS THROUGH from the drive to the mesa board," How this is gonna happen? There is an encoder output pins in the I/O CN1 in delta drive, is it through those pins? Or from the 2nd encoder CN5 to 7i77?



Can I use my 2nd encoder input TO CONNECT my linear scale direclty to the drive instead of connecting it to Mesa 7i77 or 7i76e? Or do I have to get 7i85s? Because that 2nd encoder in the Delta drive is solely for linear scale... I don't get it.

Regards,

cn1 is the pass through. cn5 is an encoder input, for an encoder that isn't on the motor - like a linear scale, or if you are deviating from the standard delta motors.

Thanks ihavenofish...

Now I got it.

So, the advantage of A2 Delta drive is that it has 2nd encoder for LINEAR SCALE like HEIDENHAIN or rls.

I have checked the B3 Delta and you completely right, they have a really fast response bandwidth and a 23bit except it doesn't have a 2nd encoder like the A2. Moreover, I got a quotation for the B3 and they are cheaper than the A2.. Also, I'm looking at the A3 series and they look awesome, but I don't know how much it cost yet.

The B3 is now on the table to be considered

Edit: Which motor should I consider the 1)High inertia 2)medium inertia 3) low inertia ?

"generaly" (there are exceptions) machine tools get medium and high inertia motors because they deal with vibrational loads.

The standard b3 motor you'll find on ebay as a kit is the medium inertia.

A3 is slightly more money than the A2, and you probably gain nothing over B3, because you are using it in a "dumb" application. most of the A3 fancy features are for when you need the drive to do more thinking.

On the lack of linear scale on the B3 - you wouldn't not want that scale going to the drive anyway, youd want it going directly to the control. its only really useful in the drive when it is commanded by position directly (as in, go to x5.345, and not a step by step command).