Spindle Ramp Up and Down

donaldo

donaldo
My spindle motor and speed control recommend ramping up the speed and then ramping down the speed. This reduces large spikes in current when starting the spindle motor and reduces back EMF when stopping the motor. Right now the output voltage is pretty much instantaneous.



Thank you!!!!
 

masso-support

MASSO Support
Staff member
Hi donaldo

You will find the ramp up and ramp down is controlled by the spindle VFD or speed controller.
Masso has a built in spin up and spin down timers that you can set, to allow time for your spindle to get up to speed and stabilize and also to stop.

Cheers Peter
 

donaldo

donaldo
Hi Peter,

Unfortunately my motor has an integral speed controller (from Anaheim Automation) and it relies on the inputs from the controller. I am hoping some day that a timer could be implemented where the user can set the time to go from zero to the set rpm and back to zero.



Thank you,

Don
 

danielmiester

New member
I too would like this option.
perhaps a checkmark on the screen that allows the existing timer boxes to function as just timeouts or as ramp times.


Maybe something like this:

[2000] RAMP UP delay (ms)
[2000] RAMP DOWN delay (ms)
[ ] Also ramp drive signal during delay <---new checkbox
 

cncnutz

CNCnutz
Staff member
Hi @danielmiester

MASSO already has spin up and spin down timers that the user can set from 0 to all day if you want built into it.
What do you mean by ramp drive signal during delay

It is the VFD's job to sort out the starting and stopping ramp parameters of the spindle.
Could you elaborate as to what you are looking for.

Maybe a manual and showing how you would use the feature.

Regards Peter
 

danielmiester

New member
I am using a servo drive with step/direction inputs, and trying to use the step/direction spindle control. (DMM Dyn4, FWIW)
Masso just starts outputing pulses at full selected speed and the servo can't keep up, as it assumes the controller will do the acceleration, and it trips out.
Obviously MASSO already has acceleration systems in place for axis controls, it'd just be nice to have that optionally be available for spindles too.
Having the step/dir outputs implies to me that it does, and nowhere in the documentation have I found any indication that this isn't the case.

I'm working around this right now by inserting an arduino to convert a PWM train into an accelerated STEP/DIR signal.
 

danielmiester

New member
And, looking at the UI, there's no reason I can be faulted for that assumption.
747d7311f1bead4a5028ff4c4c5eeb4e.png

as there are actual acceleration fields, not just timer delays
 

zombieengineer

ZombieEngineer
@danielmiester

Could you provide the vendor and model number of the VFD drive?

Part of a VFD drive is to limit the motor current to prevent burning out the motor when running at reduced RPM. If that functionality is working correctly then the spindle acceleration will be linear due to the relationship between motor current => torque => acceleration.

Due to the spindle be unloaded the power draw should be minimal and therefore the resulting electrical interference should also be minimal.

If you really need a rate limiter a simple circuit could be used (dual op-amp chip, 2 resistors, 1 capacitor)
 

cncnutz

CNCnutz
Staff member
AHHH, That makes all the difference in the world.
No one has mentioned we were talking about step and direction drive
I have been assuming VFD hence my replies mention VFD
When using step and direction MASSO should do the ramp up and ramp down.

What are your actual settings you are using in MASSO for your spindle?
I can give it a test.

Cheers Peter
 

danielmiester

New member
I'm using one of these:

I had step/dir set for 2000 steps/rev, with 2000rpm/s accel/decel
I now have it set to 200rpm/s and it still starts/stops instantly.
I'm currently using a G3Touch with v5.0 software.

Here's a video I took showing the issue.



I have the drive disabled in the vid, and the OScope connected directly to spindle pin 2 and ground, so this is almost certainly an issue on the MASSO
 

cncnutz

CNCnutz
Staff member
Thanks for that Daniel

I have now tested your settings with a logic analyzer and I can confirm what you have found.
I have created a ticket to get this looked at.

Cheers Peter
 
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