Spindle acceleration

Hello All,

I have been wondering ever since we put a new Durapulse drive in our recent retrofit about the max_acceleration value for the spindle. My question is, should I set the acceleration rate value in the drive or should I use the max_acceleration value in the INI. We currently have everything setup for a maximum of 3000 rpm and in the drive I have a value of 6 seconds to go from 0 to 3000 rpm's. Then in my INI I have a value of 50 rpm/sec as the max_acceleration rate. I think I should probably set that to 500 rpm/sec to match the drive for a 6 second accel rate. Does this make sense or am I missing something?


Thanks

Rick

I did it once for my chinese spindle, using a Yaskawa VFD. The acceleration is dependent of the eletrical and mechanical spindle motor characteristics.

The Yaskawa driver has a test routine that finds the correct acceleration ramp, given working parameters and a run test with no load on the spindle motor.

I am not familiar with the Duradrive, so, I do not know if it applies to it. But seems reasonable to.

Regards,

Dimitrios

Good Morning Guys,

I tried setting my INI value to the same as what the drive is configured for, but no luck, still having the same issue.

We did perform the Auto Tune that you were talking about, Dimitrios, and that went fine.

What if I take the MAX_ACCELERATION line out of my INI? Will Linux just give an output voltage that is not ramped?

Sorry LAIR82, I answered the wrong question! I did not finished the setup of the spindle control with LinuxCNC, I am testing the machine manualy setting the spindle rotation.

Please, forgive my lack of attention.

Promise not disturb your thread wit unnecessary comments again. I will look to what I have planned and try to test it in my control and get back to you. I have some free time this end of year.

Regards,

Dimitrios

LAIR82 wrote:

What if I take the MAX_ACCELERATION line out of my INI? Will Linux just give an output voltage that is not ramped?

The normal use for MAX_ACCELERATION in the INI file is for joints like XYZ etc.
The default linuxcnc behaviour is to not limit accel or decel. of spindle-speed-out.

You would need to add a limit2 or limit3 HAL-component on spindle-speed-out yourself to limit spindle speed acceleration. This also requires a comparator to tell when the spindle is at speed and spindle-at-speed can be set true (linuxcnc will then proceed with the G-code program. otherwise it could happen that G-code is run while the spindle is still accelerating)

Anders

That did the trick, I first #'ed out the max_acceleration line in my INI to see the affect, and ran some cycles and the problem was gone. Now I erased it all together.

Thanks

Rick