Centroid Community CNC Support Forum

good mornig.

i bought the acorn card and software few day ago, i am working on the retrofit of yaskawa drives and servomotors cnc router, my question is, as the acorn is an open loop controller, will i experiment errors in the positions? did i make a wrong choice buying the acorn and not the oak controller instead? there is a schematic sheet connecting acorn to yaskawa drives, i know the feedback encoders ends up in the drivers, and aconr card is not receiving any signals about errors, so i am confusing now, if someone have any suggestion how to make the system work as better as possible i apreciate it.

Noel

noel-nogal wrote: ↑Fri Mar 19, 2021 3:01 pm good mornig.

i bought the acorn card and software few day ago, i am working on the retrofit of yaskawa drives and servomotors cnc router, my question is, as the acorn is an open loop controller, will i experiment errors in the positions? did i make a wrong choice buying the acorn and not the oak controller instead? there is a schematic sheet connecting acorn to yaskawa drives, i know the feedback encoders ends up in the drivers, and aconr card is not receiving any signals about errors, so i am confusing now, if someone have any suggestion how to make the system work as better as possible i apreciate it.

Noel

Noel,
Which model Yaskawa Drives do you have? If they take step and direction inputs then you could use them. The drive will close the loop.
See the attached example Yaskawa Schematic

Pictures of your machine, model drives, what spindle drive you have etc. would be helpful. Under the box you type in, click on the Full Editor and Preview button, then click on the Attachments tab. Then you can point to your picture files.
Marty

drives are SGDH-05AE servomotors are SGMGH-05ACA6F with incremental encoder UTISH B17CC,
spindle drive is Yaskawa varispeed 616PC5,
the machine is a conquest 250 holz her. router, i will attach some pics.

thank you

the drivers accept step and dir pulses, you can see the page 114

noel-nogal wrote: ↑Fri Mar 19, 2021 3:18 pm drives are SGDH-05AE servomotors are SGMGH-05ACA6F with incremental encoder UTISH B17CC,
spindle drive is Yaskawa varispeed 616PC5,
the machine is a conquest 250 holz her. router, i will attach some pics.

thank you

Here is a link to the manual for those drives that I could find:
https://www.yaskawa.com/delegate/getAtt ... _0_0-1.pdf

I have no experience with them, but it appears they accept step and direction (pulse and sign)

Perhaps someone else can chime in.
Marty

yes that's what i thought, if the drives accept step and dir pulses, they must work fine with acorn controller, but i read somewhere that i will have some errors position because no feedback to the acorn card, any way i will finish this work and see how it looks like.

thank you for your help.

noel-nogal wrote: ↑Fri Mar 19, 2021 4:09 pm yes that's what i thought, if the drives accept step and dir pulses, they must work fine with acorn controller, but i read somewhere that i will have some errors position because no feedback to the acorn card, any way i will finish this work and see how it looks like.

thank you for your help.

You should NOT get errors in position. When you configure the drives for that THEY should be monitoring position....

Marty

so what is the difference between full closed loop like the oak controller and the acorn open loop, but closed loop by encoder and drive? how they make difference, i suppose the oak controller tell the software what's going on right? but what happen with the acorn? in other words, how can i see the difference?

noel-nogal wrote: ↑Fri Mar 19, 2021 6:56 pm so what is the difference between full closed loop like the oak controller and the acorn open loop, but closed loop by encoder and drive? how they make difference, i suppose the oak controller tell the software what's going on right? but what happen with the acorn? in other words, how can i see the difference?

Encoder feedback from the Yaskawa drive goes TO the Oak Motion controller, Oak knows motor position at all times. If its out of position it will command the drive to get the motor into position. If it can't it will fault an CNC12 will stop movement. Generally you can recycle the Estop and go back to work from where you left off because the motion controller knows where its at.

Acorn does not have that feedback. Acorn sends a stream of pulses to the Yaskawa drive and relies on the drive to make sure the motor turns what the drive commanded it to. The drive knows the pulse count sent to it from Acorn, and turns the motor accordingly, it monitors motor position through the motor's encoder. If the motor is struggling to get to the commanded position, it pushes it harder to get there. If it can't it faults out and tells Acorn via a Drive fault input, CNC12 will halt movement with that fault. You may or may not be able to go write back to where you left off without rehoming the machine because Acorn does not know the actual motor position, BUT if the drive is kept up during a fault, the drive will still know motor position. The Estop contactor would have only removed motor power.

You have to program the drive to be in one mode or the other.

I am over simplifying but hopefully that gives you an idea.
Attached is an Acorn System Schematic which you should follow along with the Yaskawa schematic. Use an Estop contactor. You will note on the Yaskawa schematic there is an L1C and an L2C, those are likely the logic power input to the drive which keeps the encoder live along with the drive electronics, and they are left hot and generally power up when you turn on the main switch. The motor power, L1/L2/L3 is broken by the Estop contactor.

Hope this helps a little bit.
Marty

that helps a lot, it's very good information, it mean in both cases closed loop will keep machine accurate, and also any error that the drive can't fix or keep up will stop the movement. i understand now, actually i have a small cnc with leadshine closed loop stepper motors and i think they work the same way, they are running with deskcnc controller.

thank you so much, it is very clear to me now.