Losing steps on Z axis

[A_Camera]

I can assure you that GRBL works by generating pulses for each axis simultaneously. I have read the code! I can't be certain for other motion controllers, but as an architecture it makes sense. After all, the output connections are in parallel and there is no electrical reason why one pulse must follow another rather than happen at the same time. What I don't understand is why things like the CSMIO can run so fast, much faster than necessary, if it is only used for steppers. Perhaps because of the custom hardware in the device?

Happy to continue the discussion when we have both had a night's sleep!

So, the night is over ( was too short, as usual... )

Anyway, I was not questioning that the pulses are output in parallel, of course the pulses must be output in parallel otherwise the motion would not be synchronized. The question was more on how to calculate the pulse width needed to produce the parallel pulses. But... after a night sleep I am pretty sure I was wrong in my calculations regarding this. Of course it should be calculated using the maximum speed of one axis only. In my case the motion controller is capable of handling six motors at 400kHz kernel frequency, so it should be able to produce 1.25 us pulses on each of the six outputs in parallel.

Never the less, I posted this question on the product forum of my motion controller (CNC Drive UC300ETH) to get it sorted out and answered by the developers. I could also hook up an oscilloscope and measure it, but it is better if the developers answer. Also, if it is as I now think it is, then I will reduce the kernel frequency to 100kHz since there is no benefit of using anything more that 53.3kHz in my case because of the maximum speed of 8000 mm/min and the micro stepping of 10x I am using requires only 53.3kHz and the nearest above that is 100kHz kernel. It will make the pulse width twice as wide, which is good.

Edit:

OK, it is now confirmed by CNC Drive that the UC300ETH can output 1.25us pulses at 400kHz continuously on all six motor outputs in parallel, so as soon as I get home, I will set my kernel to 100kHz. No need, and no point for anything higher than that in my machine. Still have a VERY large margin to the maximum possible speed at this kernel frequency, which is well above the limitations of my machine.