Remora - ethernet NVEM / EC300 / EC500 cnc board

For the spindle 0-10v output there is a PWM to analogue chip on the board. Remora uses hardware PWM to drive that chip. The 0 - 100% SP determines the duty cycle for the PWM.

It would help to share your config files to see what influences the SP on the LinuxCNC side as there is no interactions between the Remora modules, stepgen and PWM, running on the EC500.

Thanks scotta , ini and hal attached.
I played around with the p i d settings today in the INI but it made no difference. Dip in voltage was still there. Also when I set the gain to 0.0025 which should be the correct value for 4000rpm. It doesn't scale right. I need to input 0.02 for it to work.
 

post your gcode file, i can test it out this week. I havent tested out CSS yet, and ive been trying to figure out how it works. because with threading it runs fine, but with CSS i think it is using the spindle speed-in pin.

If spindle0.speed-in has control on the rpm signal based on the feedback it receives, that would make more sense of your issue.
You removed the lowpass filter gain from the hal file. Im not sure what it defaults to. 0.001 was the gain that worked for me without jumping around, but it took longer to stabilize at speed
Monitor this pin on the halshow, spindle.0.speed-in when trying to css, and see what it looks like.

Your spindle PID in the ini file arent hooked up to anything, so they wont do anything.

RE: spindle gain, sorry about that murphy, I got confused between some configs and got some decimals mixed up. The correct way is 100/maxrpm.

Also when I set the gain to 0.0025 which should be the correct value for 4000rpm. It doesn't scale right. I need to input 0.02 for it to work.

if it works, whatever, but maybe look into it. with gain at .02 that would make 4000rpm 8volts.

Thanks cakeslob, i put back in the filter gain. when I monitor Spindle.0.speed-in, it also dips in speed. Even with the spindle off its still moving.
G-code G96  D1500 s200 M3 sets it 1500rpm suface speed 200. When you move X in and out the spindle should adjust.  

Hi  scotta , I am based in the UK, and I am considering buying a few EC300 boards, flashing them with your amazing firmware and putting them on eBay as a LinuxCNC compatible controller. I think this would ease the way for some people into the LinuxCNC world. Would you have anything against it, or do you know if it is against any license agreements? 

When I was looking for a LinuxCNC compatible controller, the only sensible option I found at the time was the Mesa boards, which are quite expensive and require shipment from the USA to the UK. Also, probably not everyone wants to play with flashing the boards.

Let me know what you think. Thanks!

Hi Daz, no issues from my side. I'd probably do the same if I had time.

Sorry to the forum admins, I posted this in a separate thread because I wasn't sure whether to post my closed-loop question here, but my contributions to remora are directly related to this thread, so that's why this is a double post here.

It's been a while since I posted anything here, but it's never too late if you have the desire.
I've continued moving forward with my dual-head mitre saw project. I've developed a PwmGen module for Remora. At least it drives the motor, haha. Up to four modules could be instantiated, for which the four QDCs can also be used. I want this to develop a closed-loop system. Once again, I'm leaving the links to my GitHub in case anyone wants to take a look.
Scott, I know your time is short and tight, more or less like mine, haha. I've sent you a pull request on GitHub for this. When you can, take a look; everything can be improved.
I have a video of my tests online. I use a user interface I designed for a dual-head mitre saw. I welcome criticism. Although it's not very visible, I'll leave the link. It was only an open-loop test, but I was able to verify the PwmGen module works.
*****Now the questions********
I've read quite a bit about DC motor control here on the forum. For this case, I started using an old servo amplifier that the machine itself had as standard. This was controlled with a +/- 10V analog signal, which was quite a challenge to get working. The servo amplifier controlled a speed loop with a tachometer that the motor has, and the encoder is on the side of the moving head, that is, on the load, not on the motor. By the way, thanks to everyone who gave me instructions on the table cards; PCW, Tommylight, etc.

I want to skip the servo amplifier and use Remora with a simple H-bridge and the encoder. This is where I run into a problem. I need to use a PID loop in speed mode, but I don't have an encoder on the motor; I have it on the load. I'm not an expert in motor control loops, although I understand something, but I'm not sure if I can implement a closed loop with this configuration. Therefore, would it be mandatory to attach an encoder to the motor?

Greetings to all, thanks in advance.

rbobey1989 wrote:

I need to use a PID loop in speed mode, but I don't have an encoder on the motor; I have it on the load. I'm not an expert in motor control loops, although I understand something, but I'm not sure if I can implement a closed loop with this configuration. Therefore, would it be mandatory to attach an encoder to the motor?

It should work, needs some tuning and as little as possible of backlash between motor and encoder, so the answer to the last part is no, it is not mandatory, LinuxCNC does not care where the encoder is as long as they are physically attached (even with rope), and it can control DC servo motors with just a simple H-bridge.
I have done some simple drives that worked perfectly with LinuxCNC, leme see if i can find them:


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-Not very useful info bellow, feel free to skip.
And As general info, since audio amplifiers are getting really cheap, especially the D class ones, they can all be used as a servo drive, granted limited current capabilities and the only current limits built in are overload where it shuts completely down or no limiting and burns to a crisp!
There are plenty of use cases for them, but complicate things due to +-1V input sensitivity, that can be sometimes misused by bridging them and inverting one input, so only pwm should work. Some are bridged inside, so only inverting one input should do.

I did these commands but I'm getting the following error,
0010637 C Error: [__main__]

Hey Murphy, here is a small video of my lathe doing CSS. It appears to function as intended. I have included my halfile so you can compare

github.com/cakeslob/upload_things/blob/main/20180218_225707.mp4