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Context:
I want to use Linuxcnc for a Ultra-Precision machine.
For that i need Linuxcnc to tell my drives (via Ethercat) the waypoints with high resolution.
I can get 0.5 nanometer resolution out of the Ethercat bus with the 32bit Integer format at the travels that i need. Which is sufficient.

Now as for my question:
From what i gather the path planner and everything works in single-precision floats.
Doing the math on that at 10mm and 500mm positions tells me the resolution between bits of the float number is not enough.
10mm/2^24=0.59nm
500mm/2^24 = 29.80nm

I dont want to waste that much precision in my control for no reason (plus having to convert to the scaled integer value).

Is there a way to change that to double precision floats (64bit) without having to rewrite the whole control?
Also feel free to tell me that my math is wrong^^

Leo
 

when it becomes merged there will be some notes, it will be a pretty big update announcement.

Yes, I think its a good idea and something I have suggested a while ago.
Especially for multi-stage logic, simply connecting pin to pin makes more
sense.

I did indeed modify JOINT_N_SCALE to match the drive configuration and the value in the INI file. and it works fine now. The axis moves exactly with the commanded value. Changing the BASE_PERIOD value to 10000 in the firmware also increases the speed without the joint tracking error occurring.
The only drawback is that if one modifies the STEP_SCALE parameter in the drive, the firmware would necessarily have to be recompiled. That is why it seems like a good idea to remove these parameters from the firmware so that they can be modified at any time.

My first guess is that the sserial channels on the 7I74 are not enabled in the hal file
(with a sserial_port_1=00000000 stanza in the hm2_pci driver loadrt line)

Yes, 7I96/7I96S TB3 pin 12 is the input common.
Isolated inputs accept +-5 to +-36V signals relative to input common.

If you connect +24V to input common, the inputs will be activated
when grounded (connected to the 24V negative output) This
is the normal way to setup the input for NPN sensors
(or switches with a common ground)

Thank you so much for your help, your video helped a lot, I was able to flash on Stlink V2, but how do I install and use pyqcd, I didn't find anything that helped me, I could explain to me, or point someone who has already asked this question to see what He did1