G540 & EMC2 Anyone?

[725franky]

Hi, I have a g540 with a 48V power supply and 269oz steppers. I am running EMC2 and I need setup HELP!

I have the controller hooked up to an e-stop and 1 stepper. I hooked the 540 up to my computer using my EMC2 Xylotex .ini file ...just changing the steps per inch to 40000. The problem that I'm having is:

I drive the stepper for a little bit and it stalls giving me a Joint 0 following error. I've tried speeding up and slowing down the IPM as well as slowing down the acceleration. No matter what It only jogs a little bit and then stalls.

Just an FYI the stepper is not hooked up to my mill.

Thanks,

Frank

[acondit]

It sounds like your MAX_ACCELERATION is set too high for your STEPGEN_MAXACCEL, that is you don't have enough head room for the trajectory planner.

Alan

[725franky]

max_acceleration & stepgen_maxaccel are set at 5.


Frank

edit:

my max velocity is at .5



does that sound incorrect?

[725franky]

I was just playing with the controller setup the way it is and I was able to get the motor running at 10IPM with out error. Pretty much any faster than that and it gives the error.

the faster the speed is set the faster it stalls. If the speed is a around 14IPM it will sometimes run fine but stall and error out when you let off.

I tried messing with the accel some more and I even turned it down to .5 still didn't change anything.

Is the problem my computer? My mill was able to run 17-18IPM on one of its axes with my 24V Xylotex controller.

I'm confused. ...I'm really just looking to be able to rapid at around 30-50IPM...no less than 20IPM.

[acondit]

Frank,

Your STEPGEN_MAXACCEL should be about 120-125% of your MAX_ACCELERATION if I recall correctly.

Alan

[acondit]

How many threads to the inch are you using for screws? Also another thought, what is your base period and your latency? How many steps per inch were you using on your Xylotex?

Alan

[725franky]

Im not sure what exactly latency or base period are. I did do a latency test yesterday and my max jitter(that's what it said was important) was like 15000.

The motor isn't turning anything right now I don't have it hooked up to a lead screw. The IPM's are based on a 1/4 - 20 lead screw (taig mill).

My Xylotex was running like 10IPM on the z & 15-18 on the X & Y. Those were my rapid speeds.

[bharbour]

Originally Posted by 725franky ...just changing the steps per inch to 40000.

Is 40000 a typo, my misunderstanding or a problem? It seems to me like 400 steps per revolution on the stepper x 10 revolutions per inch on the machine axis should be 4000 steps per inch, not 40000. This would fit with stalling at speeds lower than expected.

BobH

[725franky]

Steppers are 200 steps per revolution machine is 20TPI and drive is 10 microsteps per step. Thus the 40,000 (200*20*10). With my Xylotex (8 microsteps) my steps per inch were 32,000 and that was correct.

[bharbour]

Originally Posted by 725franky Steppers are 200 steps per revolution machine is 20TPI and drive is 10 microsteps per step. Thus the 40,000 (200*20*10). With my Xylotex (8 microsteps) my steps per inch were 32,000 and that was correct.

Sorry, I had not realized that the 540 was a microstepping drive.

BobH

[acondit]

Originally Posted by 725franky Is the problem my computer? My mill was able to run 17-18IPM on one of its axes with my 24V Xylotex controller. I'm confused. ...I'm really just looking to be able to rapid at around 30-50IPM...no less than 20IPM.

If the problem is with your computer, you have increased the number of steps required to move an inch by 25% (32,000 to 40,000). This would result in your top speed being reduced by 20%. 80% of 18 is 14.4, 80% of 17 is 13.6. So what you are reporting is consistent with your top speed being limited by the speed of your computer.

Alan

[cyclestart]

Originally Posted by 725franky Im not sure what exactly latency or base period are.

The base period is recorded in the .ini file. For example, with your screw and 10 microstepping;
BASE_PERIOD = 50,000 gives a theoretical 15 ipm
25,000 = 30 ipm
15,000 = 50 ipm
At least I think that's right. Emc evolves quickly and there's some double-step thingy I still don't quite grasp. And then there's Gecko's morphing trickery that might also have some effect ? And of course you can't demand a base period beyond the computers capabilities. Man this stuff gets confusing !

If BASE_PERIOD is a high number (like 50,000) you could try lowering the setting until the computer starts to bog. I'm guessing however you have it set considerably lower. Maybe try running stepconf again using Gecko's timing specs ? Just plugging a new scale into an existing Xylotex .ini seems like asking for trouble

You could also ask on the emc-user-mailinglist. There's been some testing with the g540.