Configuration du driver

All things related to the Centroid Acorn CNC Controller

Moderator: cnckeith

Francis
Posts: 14
Joined: Thu Jan 07, 2021 3:18 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: System ID E415F6F2033A-1211204193
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
Location: France

Re: Configuration du driver

Post by Francis »

Why good luck?
I don't understand, if it's not good, can you explain to me?

Francis.
martyscncgarage
Posts: 9912
Joined: Tue Mar 28, 2017 12:01 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: Yes
Oak CNC controller: No
CNC Control System Serial Number: none
DC3IOB: No
CNC12: Yes
CNC11: Yes
CPU10 or CPU7: Yes
Location: Mesa, AZ

Re: Configuration du driver

Post by martyscncgarage »

If you put +5vdc to +Pul and +Dir on the drive from Acorn power supply and from drive -Pul to Acorn ST1 and from -Dir to Acorn header, it may well work fine.
The DB25 works best with 5vdc logic drives, that's why it is suggested

Marty
Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
Mesa, AZ
Francis
Posts: 14
Joined: Thu Jan 07, 2021 3:18 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: System ID E415F6F2033A-1211204193
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
Location: France

Re: Configuration du driver

Post by Francis »

I used the connection seen on the pdf S14851.
If I use only the DB25 where plug the enable?
I think that i need connect to the H2 or H3.
It's ok?

Francis.
martyscncgarage
Posts: 9912
Joined: Tue Mar 28, 2017 12:01 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: Yes
Oak CNC controller: No
CNC Control System Serial Number: none
DC3IOB: No
CNC12: Yes
CNC11: Yes
CPU10 or CPU7: Yes
Location: Mesa, AZ

Re: Configuration du driver

Post by martyscncgarage »

Francis wrote: Sun Jan 17, 2021 4:56 am I used the connection seen on the pdf S14851.
If I use only the DB25 where plug the enable?
I think that i need connect to the H2 or H3.
It's ok?

Francis.
Francis, you would apply +5VDC to ENA+ on the drive and wire ENA- to Acorn
Those drive and motors are so small, I don't think you have to worry about enable. That's up to you.

Marty
Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
Mesa, AZ
Richards
Posts: 692
Joined: Sun Sep 16, 2018 9:01 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: none
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
Location: South Jordan, UT

Re: Configuration du driver

Post by Richards »

You asked specifically about the Enable signal. My steppers DO NOT require the Enable signal. In fact, if I connect an enable signal to the stepper drivers, the drive is put in a power-down mode.

As Keith, Marty, and others have said, using the DB-25 connector for steppers and the H connectors for servos is the best policy. It's always best to listen to those who sell the board and to those who have used it extensively. I've noticed that many of the questions asked on the forum are answered in the excellent schematics provided by Centroidcnc; however, because I lived in Belgium and France to two years, and because I ran offset printing press that required knowing how to make full-sized litho-film negatives of whatever I printed, I know that technical terminology is not easily understood, if it is written in a non-native language. My native language is English. The documentation for the printing press and the lithography was written in French. My vocabulary as a missionary did not include technical terms for offset printing and film processing. So, I tried to ask specific questions, just as you have done.

I've used the H connectors with Leadshine type stepper drivers. I ALWAYS used a current limiting resistor in the Step and the Direction signals to limit the current to about 10mA. A 2,000 to 2,400 ohm resistor works. Pay attention to the heat. In theory, a 1/4W resistor works, but don't touch it! I use a 1W or 2W resistor that handles the heat better.
-Mike Richards
Francis
Posts: 14
Joined: Thu Jan 07, 2021 3:18 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: System ID E415F6F2033A-1211204193
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
Location: France

Re: Configuration du driver

Post by Francis »

Thank you for your help.
I will test the resistance in series on the signals.
I want to turn off the motors because I live in a cottage where I don't have electricity, I run on solar panels, so I try to save every milliamperes.

Are Closed Loop Stepper Motors Considered Servo Motors?
If it does and if my drivers don't work, I am considering buying 2 drivers and 2 closed loop stepper motors while they are within my budget.
Do you have drivers to advise me?
I have a 42 volt 280W power supply to power the 2 drivers.
Is it sufficient?

Francis.
Richards
Posts: 692
Joined: Sun Sep 16, 2018 9:01 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: none
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
Location: South Jordan, UT

Re: Configuration du driver

Post by Richards »

Running a CNC machine from Solar will be interesting because of the power requirements, not only of the drives and motors, but also for the spindle. Let us know how it works for you.

Stepper motors, including closed loop stepper motors, are designed to turn the shaft a precise amount, usually 1.8-degrees. That means that a stepper motor and a driver that is set to make full steps, requires 200 pulses to turn the shaft one time. Modern drivers let you subdivide the pulses to require 400, 800, 1600, 3200, etc. steps to turn the shaft one revolution.

In a standard stepper motor, the Acorn sends pulses and assumes that the motor spins its shaft as directed by the Acorn. There is no feedback from a standard stepper motor.

In a closed loop stepper motor system, the stepper motor still moves an exact distance per step pulse; however, it has an encoder attached to the shaft. The encoder has a fixed number holes or sense indicators, let's say 4,000. So, if the stepper motor is configured to require 800 steps per revolution, the encoder would count five pulses per step. (This is simplified. Many encoders are quadrature. My example is just to explain the basic operation.) If the encoder only sent one pulse, instead of five pulses, to the driver, the driver would send a fault signal to the Acorn. That's a very simplified example. In any case, the stepper motor still acts like other stepper motors; it still turns the shaft an exact distance per step pulse. You can feel "cogging" if you turn a stepper motor's shaft with the power off.

A servo motor is more like a standard AC or DC motor. If you turn the shaft by hand with the power off, the shaft moves freely with very little "cogging". I just turned the shaft on one of my Teknic ClearPath servos. There is only a small amount of "cogging" with the power off. How a servo really works depends on its drive. The basic principle is the same as for a stepper. For each step pulse sent by the Acorn, the servo driver commands the servo motor to move. The motor sends back an encoder count to the driver. The driver turns off the motor when it has received the correct number of pulses. When a servo motor stops, it still monitors the shaft position. If something tries to move the shaft when the motor is at standstill, the driver turns on the motor to keep it in position. If the load on the shaft is less than the holding power of the servo, the shaft stays in position.

No motor can move a load instantaneously. The Acorn ramps up the speed of a stepper or servo. My Acorn is set to 1/2 second. That allows the motor to get the load moving without stalling. My Teknic ClearPath servos can be configured to set the "mismatch" between commanded steps and actual steps. If the number of commanded steps is exceeds that configured number, the ClearPath sends a fault to the Acorn. Teknic provides configuration software (MSP) that not only lets you set how the motor sends a fault signal, but also to monitor the motor with an oscilloscope type screen. By watching the traces on the screen, it's easy to see if the motor is properly sized to handle the load at the speed desired.

As a wrap up, I would use standard stepper motors when I have motors large enough to drive the load at the expected speed. Those motors would be over-sized about 50% to handle the unexpected. I have never used closed-loop steppers, but I would size them the same way that I would size standard stepper, but I would not need to have them over-sized as much because they would send a fault signal. The fault signal would allow me to extend the ramp time or to reduce the load on the motor by reducing the speed or the depth of cut or other parameters. I would prefer servos motors. They are quieter, smoother in operation, and more easily configured and controlled (I'm writing about the ClearPath servos and the MSP software), but they are more expensive. The smallest ClearPath that I use costs $257. The next larger size I use costs $300. The largest size that I use costs $350 per motor. I'm still using 100 oz-in standard steppers on my Taig mill. They can move the axes on the Taig with the light cuts that the Taig can handle, due to its construction. If I used servos on that mill, I would have to stiffen each axis to withstand the added strength of the motors. If I needed the additional speed, I would consider buying a larger mill that was constructed to handle the bigger load.
-Mike Richards
martyscncgarage
Posts: 9912
Joined: Tue Mar 28, 2017 12:01 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: Yes
Oak CNC controller: No
CNC Control System Serial Number: none
DC3IOB: No
CNC12: Yes
CNC11: Yes
CPU10 or CPU7: Yes
Location: Mesa, AZ

Re: Configuration du driver

Post by martyscncgarage »

Francis,
The one bit of information you have not provided is the machine you are refitting. Please post a few pictures of it, the pitch of the axis ball screws, and reduction ratio.

Mike is provided some good information. Basically choosing the right motors/drives for the application. So many times this is overlooked.

Marty
Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
Mesa, AZ
Francis
Posts: 14
Joined: Thu Jan 07, 2021 3:18 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: System ID E415F6F2033A-1211204193
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
Location: France

Re: Configuration du driver

Post by Francis »

Thank you Mick for taking your time to explain the operation of the motors it allows me to better understand their operation For the moment as my budget is quite tight I will stay with my stepper motors and it will also allow me to familiarize myself with this type of engine as well as the Acorn software which I do not know at all.

Francis.
Francis
Posts: 14
Joined: Thu Jan 07, 2021 3:18 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: System ID E415F6F2033A-1211204193
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
Location: France

Re: Configuration du driver

Post by Francis »

Hello Martys,
The machine I'm retrofit is the Emco Compact 5.
I d'ont remember the pitch of the ball screw and the reduction ratio.
I think it must be the same as the Emco PC5. I must find the instructions.
Image
Francis.
Attachments
TOur Emco.JPG
Post Reply