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A 7I96S has an analog output

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I would always leave the stepgen in velocity mode
and use a mux component to switch the source of the
stepgen velocity command from the PID output (C mode)
to commanded spindle speed (spindle mode)

Then a change to velocity mode is trivial. To maintain
position reference when changing back to C mode, you likely
need to home the C axis to index. Does the spindle have an encoder?

If not, a single index input will do if you have 7I95T firmware
with Step/Dir index (7i95t_sdid.bin)

sorry I left out the "don't"

Evgeny wrote:

loadusr, command not found 

That line has to be in the ha; file, not in a terminal.

Sorry
/boot/broadcom/config.txt

The file is the same as the official RPi image but in a different location. This is due to the patched kernel used.

The file you have to edit is:
/boot/Broadcom/config.txt

Not /boot/firmware/config.txt
This file does not exist in Rodw’s image. You must have created the directory and file.

I downloaded Rodw’s most recent image to check. I was involved when Rod was initially making the images last year. I did a fair bit of testing.

nop, no idea
how can do that ?

My googling shows hints that WinCNC has some s-curve support. But I'm not educated enough to know how complete or useful it is. Thank you for the first hand comments about WinCNC. 

Your comment about jerk limiting in the servo highlights a hope I had wrt the Yaskawa drives I have. But, alas, Sigma II doesn't appear to have this feature. I'm also confused about how a machine can keep synchronicity while drives are doing acceleration modifications in isolation. 

If I've read correctly, you are running primarily wood cutting machines? 

Did you check cornholios suggestion?
 

do you have any idea how to enable the spi ?

spumco wrote:

PhilipME wrote:

Can someone direct me to where I find how to wire this creature?

I am using break-out-board, and BT-30 power head

 

Need more detail.

Post a copy of the user manual please, as well as your BOB manual.  If you're using a Mesa card, please identify it and how you've connected your BOB.

Thanks
the break out board is just a simple db 25 like the one in the link
store.fut-electronics.com/products/5-axi...-mach3-parallel-port

The manual for the servo driver
machmotion.com/documentation/Drives%20-%...TSTA-User-Manual.pdf

for speed mode, I thought it will be as simple as vfd spindle, on/off and analog for speed control

 

Did you mean to say you don't have ?

Or am I misunderstanding ?

Either way Pete your very very gracious with your time, even for those of us who experiment with your firmware on other hardware.

Looks good. Lots of hard work. Lots of thought gone into it.


Generally when I've been designing my boards I've followed the mesa example where all the signals from the FPGA that will be controller something go through a FET bus switch with a pullup resistor to 5v on the "world side"(I'm a cruddy old guy lol, I like 5v). Gives you bi directional voltage translation, and works fine even with the 2.5MHz SmartSerial signals (when I use mesa firmware tho my design also can run rio with no issues). To drive outputs I add a buffer or just connect directly to a simple Parallel Port breakout board.

Have you thought about screw terminals for the outputs ?
With regards to the differential outputs for the stepper drivers, it would take some serious noise to have any affect when driving an opto. I've used plain old 74 series 540/541 powered by 5 volts with no issues for years, plenty of drive there. And generally the cable length isn't all that great from between the step\dir source & destination.

Tommy linked a video to a guy that experiments with noise & shielded cables, very interesting.

For 5v to 3.3v translation 74lvc is a good candidate.

Masiwood123 wrote:

do you have a servo driver that can work in two independent modes step/dir (position), and analog input (velocity mode)? take a look at the video, I did it by introducing ``A `` as standard axis for changing the position, and the motor rotates like a classic lathe through the gcode M3 ``S``command by analog signal.
 

I saw your lathe. Yes, my servo could work with analog and step/dir. But my board 7i95T hasn't analog output. But this is not a problem (my spindle works via S3, M codes fine). Main issue for now is "when the spindle rotates in velocity mode pos-cmd change (stepgen module) it's value, but axis A (joint and pid modules) have old one". From LinuxCNC perspective Axis A have no action, but stepgen "somehow" changed it's position (because there is another module spindle and spindle.pid who send commands for velocity). To avoid this issue I'm making reset BEFORE using Axis A, and rotate to 0.0 AFTER using Axis A (so stepgen pos-cmd became 0.0, joint became 0.0, pid.a became 0.0). Then I making reset (block pos-cmd to change it's value) and start working with Spindle (velocity mode). So only in this case pid.a == joint == stepgen.pos-cmd == 0.0 EVEN is stepgen is rotating via Spindle commands.
So if you have tips how I could switch back to Velocity mode without rolling back to pos-cmd == 0.0 -> please give an advice.
How to fix out of sync joint/pid.a-axis pos-cmd with stepgen, when spindle/pid.spindle works with the same stepgen. I feel it looks like the problem should be resolved in 1-2 rows in HAL/INI file.