Centroid Community CNC Support Forum

By the way, many analog DC servo drives accept -/+ 0-10vdc signals. Acorn can only supply a 0-10vdc signal so it could only drive a motor in one direction.

martyscncgarage wrote: ↑Wed Dec 26, 2018 6:20 pm All in One DC is a Centroid control designed with three DC servo brush servo amplifiers.

Sorry, meant Centroid Acorn.

Chaz wrote: ↑Wed Dec 26, 2018 6:44 pm

martyscncgarage wrote: ↑Wed Dec 26, 2018 6:20 pm All in One DC is a Centroid control designed with three DC servo brush servo amplifiers.

Sorry, meant Centroid Acorn.

So you are going to buy DC Servo drives that take step and direction signals...

martyscncgarage wrote: ↑Wed Dec 26, 2018 6:53 pm

Chaz wrote: ↑Wed Dec 26, 2018 6:44 pm

martyscncgarage wrote: ↑Wed Dec 26, 2018 6:20 pm All in One DC is a Centroid control designed with three DC servo brush servo amplifiers.

Sorry, meant Centroid Acorn.

So you are going to buy DC Servo drives that take step and direction signals...

Yep, considering these.

http://shop.cncdrive.com/index.php?productID=366

DG4S-16035 - DC servo drive

Power: 160V and 35A.
Opto-isolated step/direction inputs.
Tuning through USB port.
RJ45 connector for PLUG&PLAY like easy connection.
Selectable 2x and 4x encoder logic.
Step signal multiplier with selectable 1x, 2x, 3x, 4x, 5x, 6x, 7x, 8x, 9x, 10x options.
Setable servo error limit from 2 to 20000 encoder counts.
Fast 32bit advanced PID algorithm with 16bit PID parameters and setable sampling time.
Current limiting, adjustable from 0 to 35Ampers.
Servo error viewer software and diagnistics.
Build-in 32bit DRO (digital readout).
Step response analiser in software.

martyscncgarage wrote: ↑Wed Dec 26, 2018 11:50 am

Chaz wrote: ↑Wed Dec 26, 2018 11:14 am

martyscncgarage wrote: ↑Wed Dec 26, 2018 11:11 am

Why don't you post pictures of your new machine, including servo motors, servo drives, spindle motor and current spindle drive and the control cabinet....

Marty

I will do. I've got the original motors, been fitted with modern encoders (AMT 102). The rest is pretty standard, no electronics at all.

There is great interest in seeing the AMT Encoders run with All in One DC.....there isn't a reason it shouldn't work.....but I am waiting on AMT's larger format encoders due out the first quarter of 2019 to test them.

How did you fit the encoders to your motor shafts? The encoder stub must have been small enough to accomodate them? Did you take pictures of the install?

Marty

Just looking at the motors (I have one to measure in my office), they dont have AMT 102. They have ROD 450 B which look like old Heidenhain encoders, potentially not differential which is a problem. Ill find out why the seller said they were AMT 102 if not.

Chaz wrote: ↑Wed Dec 26, 2018 7:24 pm

martyscncgarage wrote: ↑Wed Dec 26, 2018 11:50 am

Chaz wrote: ↑Wed Dec 26, 2018 11:14 am

I will do. I've got the original motors, been fitted with modern encoders (AMT 102). The rest is pretty standard, no electronics at all.

There is great interest in seeing the AMT Encoders run with All in One DC.....there isn't a reason it shouldn't work.....but I am waiting on AMT's larger format encoders due out the first quarter of 2019 to test them.

How did you fit the encoders to your motor shafts? The encoder stub must have been small enough to accomodate them? Did you take pictures of the install?

Marty

Just looking at the motors (I have one to measure in my office), they dont have AMT 102. They have ROD 450 B which look like old Heidenhain encoders, potentially not differential which is a problem. Ill find out why the seller said they were AMT 102 if not.

Yes, those are the ones to vet if you are going to use DC brush servos with Acorn. Encoders compatibility is important or in my experience they are all but impossible to tune. Tuning must be done with their software before connecting to Acorn.
Use the encoders suggested by the drive manufacturer.

Anymore I'm pretty content with DMM Technologies AC Servo drives and motors. Far easier to deal with than tuning DC servos (correctly).
Marty

martyscncgarage wrote: ↑Wed Dec 26, 2018 7:55 pm

Chaz wrote: ↑Wed Dec 26, 2018 7:24 pm

martyscncgarage wrote: ↑Wed Dec 26, 2018 11:50 am

There is great interest in seeing the AMT Encoders run with All in One DC.....there isn't a reason it shouldn't work.....but I am waiting on AMT's larger format encoders due out the first quarter of 2019 to test them.

How did you fit the encoders to your motor shafts? The encoder stub must have been small enough to accomodate them? Did you take pictures of the install?

Marty

Just looking at the motors (I have one to measure in my office), they dont have AMT 102. They have ROD 450 B which look like old Heidenhain encoders, potentially not differential which is a problem. Ill find out why the seller said they were AMT 102 if not.

Yes, those are the ones to vet if you are going to use DC brush servos with Acorn. Encoders compatibility is important or in my experience they are all but impossible to tune. Tuning must be done with their software before connecting to Acorn.
Use the encoders suggested by the drive manufacturer.

Anymore I'm pretty content with DMM Technologies AC Servo drives and motors. Far easier to deal with than tuning DC servos (correctly).
Marty

And this is my other option. The reason I was looking to resuse the DC motors was simplicity, no mechanical changes etc however Ive run DC motors before, pain in the ass in terms of maintenance and their performance based on the size is poor, nevermind the potential tuning issues.

Unless you have an unusual mount, DMM now has motors in common NEMA sizes

martyscncgarage wrote: ↑Wed Dec 26, 2018 8:00 pm Unless you have an unusual mount, DMM now has motors in common NEMA sizes

Thanks, I believe these are considered 110mm frame size. I spoke to someone on Youtube that installed 750W servos (some go up to 1.5 KW size) - the biggest issue is getting the correct pulley setup. The motors I have, have a 15.8mm shaft size. The servos tend to be 19mm and shorter. He had to turn some 'extenders' to allow him to use the pulleys which I wanted to avoid doing.

I can replace the pulleys, my local supplier sells a similar pulley but not as few teeth as I need to keep it consistent. I could go to a larger ratio (slight difference) but then I need to get a belt and the amount of tension that will work. Ill update some pics today.

!f the shaft size is 15.87mm, then those are 5/8" Imperial sized shafts.