Centroid Community CNC Support Forum

Hello,

I am looking to use an Acorn from my CNC conversion.

My question is what is the Acorn's max output frequency for the servos?
I might be blind, but I cant seem to find the spec anywhere.

I am using Teknic SDHP servos which can go up to 64K pul/rev. I want to know how much I will have to reduce the pulses/rev of the servo to still hit 300 in/min feed rates. This will determine the resolution of the servos/ moves that are achievable.

Thanks.

SDHP probably has the same input circuit as SDSK (I'll let you verify). There are recommended settings proven with SDSK here:viewtopic.php?f=60&t=5531

Its more about the wiring used to carry the step pulse train RELIABLY between Acorn and the drive. Centroid is only going to suggest what they have tested based on the material/components the manufacturer provides. For that answer you need to ask Teknic that question.

What kind of machine and what sort of rapid speeds are you expecting?

Marty

rk9268vc wrote: ↑Thu Apr 15, 2021 1:26 pm Hello,

I am looking to use an Acorn from my CNC conversion.

My question is what is the Acorn's max output frequency for the servos?
I might be blind, but I cant seem to find the spec anywhere.

I am using Teknic SDHP servos which can go up to 64K pul/rev. I want to know how much I will have to reduce the pulses/rev of the servo to still hit 300 in/min feed rates. This will determine the resolution of the servos/ moves that are achievable.

Thanks.

You dont mention what type and ratio of gear/screw reduction you are using. This is required to calculate required step pulse. I would suggest that you set the servos to 6400 steps per rev and test from there. As an example, driving a 5mm pitch screw, this will yield ~117K steps per inch or ~0.00001 step resolution. Virtually "unobtanium" in the DIY world.

117,000(steps per inch) x 300 (ipm) / 60(sec per min) = 585K pulses/sec or 2.9 times the 200k published limit. Also unobtanium

martyscncgarage wrote: ↑Fri Apr 16, 2021 10:15 am What kind of machine and what sort of rapid speeds are you expecting?

Here are the servos I am using
https://www.teknic.com/model-info/CPM-S ... voltage=75

My question is more asking how fast the acorn can pulse on and off.

For example, a BRX PLC can only pulse on an off its high speed outputs at 250kHz
If I wanted to use the servo's full resolution of 6400 pul/rev and the full speed of 3000prm, I would need to pulse the output at 320kHz

It is for a mill not a lathe

Thanks

rk9268vc wrote: ↑Fri Apr 16, 2021 11:34 am

martyscncgarage wrote: ↑Fri Apr 16, 2021 10:15 am What kind of machine and what sort of rapid speeds are you expecting?

Here are the servos I am using
https://www.teknic.com/model-info/CPM-S ... voltage=75

My question is more asking how fast the acorn can pulse on and off.

For example, a BRX PLC can only pulse on an off its high speed outputs at 250kHz
If I wanted to use the servo's full resolution of 6400 pul/rev and the full speed of 3000prm, I would need to pulse the output at 320kHz

It is for a mill not a lathe

Thanks

400k is in the Wizard. No problem

rk9268vc, I think you are missing the point. Whilst Acorn's Max pulse rate is 400 kHz as Marty states, you really MUST take very careful notice of what others have posted above AND most importantly, study the link that eng199 has posted which includes in depth testing that Centroid have done with this equipment.

Nigelo wrote: ↑Fri Apr 16, 2021 12:17 pm rk9268vc, I think you are missing the point. Whilst Acorn's Max pulse rate is 400 kHz as Marty states, you really MUST take very careful notice of what others have posted above AND most importantly, study the link that eng199 has posted which includes in depth testing that Centroid have done with this equipment.

Agreed....he got his answer....