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unknown wrote:

Customised firmware, based on the available source, is no issue to have built. So far I haven't seen requests for new firmware features. Maybe this has happened I can't say for sure either way.

Does this qualify:
forum.linuxcnc.org/30-cnc-machines/31792...rofit?start=20#85721

I wouldn't call my solution a preferred one, it's just the implementation I chose.
Please ask questions and do some research, I'd hate for my way to be sub par and lead another member the wrong way. So far nothing has gone wrong.
If you do find any info to the contrary I would be most appreciative if any failings in my advice were pointed out.

Rob

They do seem somewhat robust, but there is always a chance. Not to sound like a doom goblin.
Whilst I have no empirical evidence, not having the resources nor $$$ to test, I feel (for lack of a better word) that Ethernet does provide some electrical isolation as opposed to direct GPIO connection.
Ethernet also frees you from being shackled to a single platform.

Tommy provides some very good information. Whilst to forum may appear to be a little biased based it would come down to a few points.
Tommy's mention of performance.
Reliability.
Wide range of options regarding hardware.
Many many more inputs than via GPIO.
The fantastic support from PCW, even when dealing with cloned items bought off AliExpress, or those building there own custom boards using dev boards and hashed together sundry parts.
Customised firmware, based on the available source, is no issue to have built. So far I haven't seen requests for new firmware features. Maybe this has happened I can't say for sure either way.
And finally, which I almost forgot, the knowledge of many of the forum members.

forum.linuxcnc.org/10-advanced-configura...ning-detailed-how-to

I didnt expect a hickup in the virtualbox can interfere functionality of linuxcnc. But after restart, i can not reproduce this problem in axis and flexgui. 
I have  version 2.7
Lucky its solved by itself. 


 

First time retrofit to linuxCNC, using pncconf to tune the PID loop.

Any advice would be great on initial pid settings.

glentek velocity/tach servo amplifiers SMA7215 
Single ended 1000ppr encoders

Critical response achieved on each servo amp, it is not overdamped yet when i adjust I/D/BIAS/DEADBAND it overdraws

Any advice for first time setup would be very much appreciated

 

In short:
RPI can do at most 20000 steps per second, if lucky and with a bit of fiddling (this is from what i read here, i stopped using RPI since version 3B)
Mesa can do 10000000 (10 million) steps per second on any or all pins, if pushed, does 1-4 million for years on end, can use any pin as input or output, does steps, encoder counts, PWM, on any pin (the FPGA part), can be programed as needed, extremely reliable (i have over 80 or 100 or i have no real clue in daily use on industrial machines weighing several tones without a single issue ever for many years), and by far the best support on planet earth in the form of PCW.
Yes i am biased, from experience, no i am not payed by them, and yes any price you see for Mesa boards i have to pay at least twice that, and i pay it gladly for the piece of mind i get with them, i can sleep calmly without worrying something might fail.
-
As for RPI, i personally use old "enterprise" PC's and some laptops, so if you can find such things it is another alternative, i can get Lenovo T470 for 120-150 euro, with 14" touchscreen, battery, plenty of RAM and NVME, with built in network jack, for me this is much cheaper than any RPI combo and more powerful and usable.

What version of linuxcnc?

Hab mich Undeutlich ausgedrückt.. G54 hab ich auf die Bohrung gesetzt.,auch auf der Ecke mit G54 das selbe Ergebnis. Für beide hab ich jeweils einen G Code Generiert. Problem hab ich Temporär gelöst durch Antasten der Bohrung und setzen des Nullpunkts G55 auf die Bohrung. Anscheinen ist es immer ein Problem wenn ich den Nullpunkt auf G54 setze.

Huh... I've not experience a properly powered and cooled rPi going bad. Maybe I've been real lucky?

Does the Mesa support tighter step timing accuracy than the "base thread" step generator?

I was not aware that the Mesa gave improved performance? Is there a reference-able document that gives a *quantitative* analysis of this performance gain?

Thank you,

BB

Ahh, well, so it goes. I've ordered a 7I76U because I think that the D models were actually going to be more difficult to wire anyways, as I'd like some sourcing outputs.  I'll see about getting an RMA for the 7I77D I have, and can function test the existing 7I76D when I get the new 7I92TM.  5 axis + spindle and 48 I/O pins should be plenty to get this mill up and running, and that leaves me some boards to experiment with in the future

Thanks for the quick replies, nice to keep momentum up on the project!

Put it this way, if the RPi5 goes bad for whatever reason, you'll have to get a new Raspberry whatever, but if you go with the 7i96 any machine with an Ethernet Port will slip in, copy your config over and you're good to go. Hardware step generation, Mesa, et al, will be smoother than software step generation.

Apparently it fell asleep!

Good evening,

It appears the Wiki is having trouble. Is there an alternative place to get the information?
I am getting a "Site not found" error.
I cannot figure out how to include a screenshot.

Thank you,
-T

Hello all.  It's been a couple of years since I got my machine, a 3 axis knee mill with steppers and linear encoders, working and I'm now finally getting around to something I've been wanting to do for a long time but I've probably forgotten most of what I learned while setting up this system and would rather not break it so I thought I'd ask first before I start tweaking the cfg/ini files. 

The goal is to increase the accuracy.  When I command it to go to a position it gets close (within .001) but I'd like to halve that if not better.  Do I remember correctly that this is the DEADBAND value in the .ini file?  It's presently set to .001 (at each joint), I have 5um encoders which my notes say corresponds to .0002" so I'm thinking I could go to a DEADBAND value of .0005 and maybe all the way to .0002.   My stepper controllers are presently set at 200 steps/rev, I can increase that by A LOT with DIP switch settings.  I have .200"/rev leadscrews and 1:2 pulleys (big one on the leadscrew) so one motor rev is .100" of movement.  At 200 steps/rev that corresponds to 2000 pulses per inch which is what I have for the STEPGEN_SCALE value.  That means I have .0005" per step.  So that has me worried that changing the DEADBAND value to .0005 might cause it to start oscillating since I'd be requiring that it gets withing one pulse.  Does it make sense to change the stepper controller DIP switches to 1000 steps/rev  and the STEPGEN_SCALE to 10000 to avoid this?  That would change it to .0001"/pulse which is smaller than the encoder.  Does the position feedback handle the situation where it sends multiple pulses before it sees a change in the encoder?  If I change the DEADBAND and STEPGEN_SCALE values in the .ini file do I have to change anything in the other files to correspond with this? 

Am I correct that this likely changes the max speed I can run at.  What breaks it I try to jog it too fast.  I'm presently using these values:

STEPGEN_STEPLEN = 2000
STEPGEN_STEPSPACE = 2000
STEPGEN_DIRSETUP = 2000
STEPGEN_DIRHOLD = 2000
STEPGEN_DIRDELAY = 4000
STEPGEN_MAXVEL = 0.25
STEPGEN_MAXACCEL = 0.25

BTW, all three axis are the same.

thanks in advance for any input