Spindle Ramp Up and Down

[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]

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]

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]

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]

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]

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]

And, looking at the UI, there's no reason I can be faulted for that assumption.

as there are actual acceleration fields, not just timer delays

 

[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]

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]

I'm using one of these:

DMM | NEW DYN2 AC Servo Drive | AC SERVO DRIVE | AC SERVO MOTOR | ROTARY ENCODER

DMM Industry Standard, High Performance, Reliable, Low-cost AC Servo System for Industrial Automation Motion Control

www.dmm-tech.com

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.

New video by Daniel De Jager

photos.app.goo.gl

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]

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

 

[martijn lanser]

Hi Peter,

Is there any news because I’m running a servo as well
I tried 0-10v and it is having the same problem is goes in one step to its target voltage
Is there a way that the masso-controller will output nice ramping up-down signal?

Regards martijn

 

[cncnutz]

Ramp up and down was added in version 5.01 for the step and direction as well as PWM spindle control. There is no ramp up or down speed control for the 0-10v output as this is for VFD and the VFD manages this itself.
Cheers Peter

 

[martijn lanser]

Hi Peter,

the step/direction spindle control is working great
thanks for your comment

Regards martijn