Remora - ethernet NVEM / EC300 / EC500 cnc board

cakeslob wrote:

Found file(REL): ./10_remora-nvem.hal
ERROR: PRU base frequency incorrect
remora-nv: rtapi_app_main: Operation not permitted (-1)
./10_remora-nvem.hal:8: waitpid failed /usr/bin/rtapi_app remora-nv
./10_remora-nvem.hal:8: /usr/bin/rtapi_app exited without becoming ready
./10_remora-nvem.hal:8: insmod for remora-nv failed, returned -1
Shutting down and cleaning up LinuxCNC...

Please not the lines....
ERROR: PRU base frequency incorrect
remora-nv: rtapi_app_main: Operation not permitted (-1)



According to the component, the range is between 40,000 and 120,000.  500,000 exceeds the range and the component doesnt load. 

Change your PRU_base_freq to 100000 and see if it loads. 

The PRU_base_freq needs to match what is in your config.txt

Let me be extra clear, the configuration file for the ec500 as far as thread frequency DOES NOT APPLY.
But the remora-nv and the frequency inside the .HAL FILE DOES APPLY.
Use my remora-nv to allow you to unlock the 500,000 frequency. This frequency tells remora-nv and LinuxCNC that it is allowed to make steps that go up to 500,000hz otherwise you wont be able to take advantage of the full 500,000hz dma step generations. But again I can only do 200,000 because of my drivers being limited, so technically in my hal I could put 200,000. LinuxCNC/Remora-NV will limit itself to that frequency as far as maximum steps per minute. The configuration file for the ec500 should not contain any frequency adjustments if you are using DMAStepGen. I hope that clears things up.

frayja2002 wrote:

Everything looked like it worked properly.

I erased the board first with
pyocd erase --chip --target mimxrt1050_quadspi
flashed the firmware... No errors
PO/PO
Had some red output light on (expected)
Modified & uploaded the config file... No errors.
PO/PO
Rel light now go out after 2 secs (expected)
Start linuxcnc & home & jog. Look in halshow... Everything seems OK.

in "remora-nvem.ini" I have PGAIN = 100. Could that make a difference. What is a good value for higher speeds?

Thanks for the quick response.
Alex

as far as I know I am the only one here so far above 1000 steps per unit here. I have my PGAIN at 88, but its still a little high and causes oscilation and of course this depends on your ping time to the card to, I believe. Not a whole lot but it is a small factor, I would recommend nothing above 80 if you are running 1000 steps per unit and unit being mm. Or step scale sorry. I would also recommend that all your step scales are positive or negative to make things simpler. So if you have your drivers wired backwards being A and B on your driver i would flip it or vice versa to get all your drivers to go in the positive direction when the stepscale is positive. At least for me this made things a lot more stable. I would recommend you use the HAL scope in run mode and jog the machine back and forth to find your perfect pgain/ff1gain, you can run the halcmd in a terminal which I believe I explained above in order to change the remora ff1gain and pgain on command as you are testing with the hal scope, you should move the pgain as much as possible to get the ferrors as low as possible and ff1gain is what will help you get rid of the curve to a point. PGAIN is the correction speed or how fast it corrects in the algorithm but if you set it too high you will get oscillation. Someone else if I have this wrong please correct me.

Wow .... after folowing @scotta 's instructions I was able to unleash the full potential of the EC500. 

I'm using CL57 closed loop stepper drivers and I was able to step so fast , with the motor on the desk, that I got a following error from the motor driver itself before I got it from LinuxCNC. I have the driver setted up for 1600 steps per revolution. 

I just wanted to give some positive feedback . This is awsome.

Hello guys, it's good to see that this project is growing in all directions, I congratulate Scott once again for his work.
Well, to the mess, today I started looking at some Steppers Motors on AliExpress and Ebay, to my surprise I can't find closed loop motors with single-ended encoder, I only see differential encoders, we don't have differential inputs in the EC500 or the EC300, I have done tests in the past using only signal A and B in differential encoders (discarding A/ B/), but it depends a lot on the hw design made on the encoder pcb and the differential IC used since the output stage is usually not referenced to Earth, having said this from my point of view the best thing would be to use a differential->single-ended converter which I have seen on AliExpress or simply use single-ended encoders, if anyone can add ideas in this regard they are welcome

Do you guys have any recommended DC or AC servos to replace Nema 24/25? Same frame size?

Frame size you might have some searching to do, they have 60mm frame size but Im not sure the nema equivalent.
Im fairly sure AC servos will be better, as the motors will probably be 200v. I dont remember if the ac servos get converted back to DC anyway.

When it came to sourcing the motors between AC and DC, my main deciding factor became supply voltage. I found it hard to source the servo drive with my voltage requirements for AC servos, as most I came across were 220v, where DC servo drives I could use 48v DC. My machine is a 110v machine, so it was the deciding factor. If you do not have these limitations, probably go with AC

I noticed that there are two different firmwares in two different locations on GitHub for the NVEM, one in Remora-NVEM/Firmware and the other one in Remora-NVEM/Remora-NVEM-STM32/Firmware.
Which one is the correct one to use for NVEM with STM32F207?

Edit: While browsing around Scott's GitHub I also noticed a repository called Remora-RT1052-cpp. Is this what I should use? If so, from where should I download the remora-nv component? I cant find it in that repo.

Edit 2: Never mind, I saw that the Remora-RT1052-cpp is for boards with RT1052 micro controllers. My initial question is still valid though =)

Hi Tommylight, I appreciate your comment and I did connect encoders this way you mention in the past and some worked and some didn't, at least not without minor modifications lol. Maybe I didn't explain myself well before, the simplest thing would be an npn-output single-ended open-collector pin-to-pin encoder without confusion, but the first thing I think about when I work with encoders is the noise in the signals because the high switching frequency applied to the stepper coils, it is incorporated into the counting signals, which is why I find it very interesting to maintain the differential channels at least as far as inside the electrical panel. The other thing that I thought about but did not explain clearly in my previous comment is that in closed motors loop that I looked at on ebay and aliexpress doesn't say if the encoder outputs are open collector or not (since the pullup and puldown resistors are added in series to the optocoupler photodiode and can cause unwanted counting pulses), if they are NPN or PNP outputs, or if they are Push-Pull type outputs, and the million dollar question would be if anyone knows of closed loop motors with these characteristics that they can share that would be great hehehe, greetings to all.

chrstrvs wrote:

I noticed that there are two different firmwares in two different locations on GitHub for the NVEM, one in Remora-NVEM/Firmware and the other one in Remora-NVEM/Remora-NVEM-STM32/Firmware.
Which one is the correct one to use for NVEM with STM32F207?

Edit: While browsing around Scott's GitHub I also noticed a repository called Remora-RT1052-cpp. Is this what I should use? If so, from where should I download the remora-nv component? I cant find it in that repo.

Edit 2: Never mind, I saw that the Remora-RT1052-cpp is for boards with RT1052 micro controllers. My initial question is still valid though =)

this is the firmware you need github.com/scottalford75/Remora-NVEM/blo...NVEM-STM32-1.0.0.bin
None of the config.txt I provided for the board will work, because you have a NVEM-STM32 those require different board configs. if you check this repository there should be example configs that work.