OK i had it hitting 600hz with different settings, ill have another play and get another video.
Thanks for the tips!
Im also about to order some more steel and fab an EMI enclosure for the AMC (despite allot of searching I couldnt find a pre-made di-cast enclosure with the right dimensions). Maybe a good enclosure will help with the noise
Did some more investigations and trouble shooting at the weekend to try and get to the bottom of the jitter issue,
Moved the amc out and away from the cabinet and set up 1 vfd to test and eliminate any issues with EMI from the VFD's, jitter the same so not an emi issue.
Also ordered 1 sample of the more expensive ball bearing pot a week or so back and hooked that up, jitter still the same so not a pot issue. (will be handy to keep as a spare)
I also concluded after trying to capture the problem frequencies better that the mini dso201 oscope i bought is basically rubbish inconsistent readings or no frequency readings at all.
So i decided to get a little more serious and order a Hantek DSO5102p like this one:
Still a hobby model but is mod-able to 200mhz via custom firmware and analysis tools look a hell of a lot more informative and easy to identify problems vs the little DSO.
Aside from that spent allot of time watching youtube videos and reading about LC filters, how capacitors and inductors work and how to use oscilloscopes. This project is becoming a bit more involved than i though! but i can say im learning allot at least.
yes dont really have much choice Michael, with this jitter issue the platform runs horrible and ive checked about every other possibility.
The 0.1uf caps definitely help so this seems to be on the right track just need to find the problem frequencies.
Im also just reading about ground loops in case that is a possible cause.
On the other hand i could be completely off target and maybe it is a PID issue but since im getting jitter even with the pots zeroed by hand before any rotation i think not. Ill be watching to see how you get on with yours and maybe you will have some advice
one thing ive learnt, SY cable is not emi shielded..! and yep i used SY for cable to motor from vfd!! so looks like im ripping that all out and changing for CY. Also didn't realise your supposed to terminate the shield to ground at both ends. fortunately i used CY for the signal leads to amc. . for the pots i used shielded audio cable and used the shield for ground. Only concern there is that is very thin gauge 28-30 so impedance will be higher. although its only 5v so hopefully this is OK??. might try a different cable during testing to be sure.
That looks great with the 0.1uF cap. The remaining noise should be coming from the sensor side as they are in the same loop. What you can do is to add an 0.1uF cap on the sensor leads too, between Vout and GND. If not much difference, add another 0.1uF cap on the Amc1280usb side on the terminal connector.
Filtering is tricky business. If I only could filter all noise on the board I would, but the control loop extends to devices outside the board as well (wiring, PSU, VFD, sensors, etc).
It will never be flat line, but the smaller the noise Pk-Pk the smaller the impact it will have to the control loop.
1 at each end of the sensor cable (not sure this is being that effective need to test more)
2 at the amc 10v out and 1 at the vfd 10v analog end. (caps at the 10v have the biggest impact)
This is the result now its silent now at pot home. less than 400khz.
im thinking a filter on the AC input might also help but if i understand the VFD acts like a switching PSU so noise is generated after the AC input. Im fairly sure most if not all of the noise is coming from the VFD end.
Or maybe some larger caps on the loop side to kill the lower frequency?
Well i found a superb guide to wiring vfd's and control cabinets today. Really wish id found this before putting my cabinet together. Has just about everything needed in this to wire things up including types of cable, routing, termination, noise management.. a must read for anyone starting their project.
dureiken: Hi there, it's really quiet here someone could help me for my 6 dof project ? thanks a lot
Aug 8, 2017 15:34:46 GMT
tronicgr: dureiken Hi, Open a thread and I'll try my best to help. A little busy with Kickstarter details at the moment but I'll see what I can do.
Aug 12, 2017 11:57:42 GMT
dureiken74: I just did it
Aug 27, 2017 11:59:06 GMT
fimmy: How's the firmware going?
Sept 6, 2017 8:34:43 GMT
tronicgr: @fimmy I had to put it on hold to finalize the manufacturing of the new kickstarter controllers. I tested parts of it to ensure compliance with the new features and looks good so far. I'll get back to it soon for integration.
Sept 9, 2017 12:52:35 GMT
Theuns: Very nice design.I'm also busy with mine and changing it also to Linear Actuators with 220v Servo motors.I'm waiting for my new controllers from Thanos. If I may ask Do you have any Sketchup files of your design and willing to share it I Thanks Theuns
Sept 14, 2017 22:45:09 GMT
atayeu: Hey everyone! I'm reading up and gathering all of the intel I can find for my first motion platform. this is by far best information for creating one.
Oct 14, 2017 7:25:57 GMT
tmcnam: I must be crazy but I still can't find the blueprints to the platform by GA-Dawg. Any help would be appreciated. Thanks guys.
Mar 10, 2019 21:31:57 GMT
Trip Rodriguez: Sorry tmcnam, the shoutbox doesn't get much attention. Did you find the blueprints? They are at the VERY bottom of the extremely long first post. It says "attachments: 6DOF.zip
May 4, 2019 19:13:25 GMT
zivby: How much weight this setup can carry?
May 19, 2019 11:57:16 GMT