Other ways to interface with LinuxCNC

Have you found the STMBL project? Open-hardware and software running on the STM32 to run moderately large servos.

github.com/rene-dev/stmbl

Thank you all for the links!
You are right, we are getting somewhere. Now that I think about it, there actually isn't anything weird about my hardware. I was just so hyper focused on my past attempts that I did not think it is plausible that any ready made hardware would work well for me.

Time for some specs:
I am using BTS7960 DC motor drivers like shown here: www.amazon.com/HiLetgo-BTS7960-Driver-Ar...urrent/dp/B00WSN98DC . 43A and I got them for around 8€ each. IIRC there are 2 direction pins and 2 PWM pins, but I chained them together to have one pin for right direction, one pin for left direction, and one common PWM pin. All 5V. Additionally there is a Current-Sense pin but I did not use them.

On the other hand, I have the encoders, they consist of IR leds and sensors, and a very simple PCB that rectifies the signals to be a sharp 5V quadrature signal. So yes, quadrature. Reference mark is yet to come.

In the past, I did not find any boards that are good in decoding quadrature inputs and that are still cheap and not part of a massive system, so I was trying to read the quadrature signals with the Arduinos directly. The Interrupts were too slow, so I used the Arduino MKR Vidor 4000 which has an FPGA as well as an MCU, and used the FPGA to decode the quadrature signals, and to do the PID loop at a very high frequency.

That being said, yes, if there was a LinuxCNC compatible board that takes in 5V quadrature signals and puts out PWM and direction signals for the BTS7960, I would spend money on it. It would still allow me to experiment with my own encoders and the concept of reference marks, and so on... Open to board suggestions, thank you

According to your other posts in the link, you got the BTS7960 to work nicely with Mesa cards, right? Is there also an example of an Ethernet Mesa card that will work for this? I am not a fan of the parallel port in general and would like to move away from it, since most PCs (even older ones) don't even have it anymore and Ethernet is a lot more future proof.

My machine currently has 3 axes, but I would like to have at least the possibility for 4 servo axes and a spindle, as well as some digital I/O and MPG.

HerrNamenlos123 wrote:

That being said, yes, if there was a LinuxCNC compatible board that takes in 5V quadrature signals and puts out PWM and direction signals for the BTS7960, I would spend money on it. 

Ethernet:  store.mesanet.com/index.php?route=produc...rt=p.price&order=ASC
PCI:  store.mesanet.com/index.php?route=produc...rt=p.price&order=ASC
(I don't think that any of the PCIe or EPP parallel port cards are currently in stock, which is a shame as the 7i90 (EPP / SPI) card would do what you describe and is only $59)

Last time I bought a Mesa FPGA card I chose the 6i24 PCIe card, as it offers a lot of IO pins for the price. 



 

If you’re a DIY guy have a look at Litehm2 project. I’m from Australia and the FPGA board was about $35 delivered. Uses the same drivers as a Mesa card. Has the same functionality as a Mesa card.
In saying all that from a “plug and play” perspective the Mesa cards are very very good value. Especially when you start costing what is takes to do voltage translation and the like.

Cant do this anymore bye all wrote:

Especially when you start costing what is takes to do voltage translation and the like.

And the screw terminal blocks, those things add up fast.