[EngineerTex]

I have experience with a couple of stepper motor projects, but I’ve never done a thing with servo motors. Now I have to do something with servo motors.

I have a Gerber Sabre 404 CNC woodworking router. It’s got a proprietary drive controller, but off-the-shelf servo motors and motor drives.

The motors are brushed DC motors - GEC Alsthom Parvex Model Number: RX32ER1026
The motor drives are Elmo Model Number: SSA-8/100
Here is the link for the motor drive: http://www.elmomc.com/support/manuals/MAN_SSA_UG_EN_0698.pdf

So here’s the problem: the motor drive controller has issues now and it’s an old machine, so I’m looking at retrofitting the drive controller board. I’m pretty confident that the motors and drives are working, so I want to keep as much as possible.

As I see it, I have the following options:

1) Install a drive controller board that can run the old drives and motors (my preferred option).

2) Install Masso drive controller board and replace drives. There is a user here (@ned_seven) who is doing exactly this project.

3) Install some other brand [what brand?] drive controller board along with new motor drives.

Where I’m unsure is what kind/brand of driver controller board to use to drive the existing motor drives. These old Elmo drives (from the 90’s) have some additional/unknown (to me) interface positions on their terminal blocks. (Link above).

So I think that with servos, there’s something a little more complex than just a stepper motor breakout board between the PC and the motor drives. I’m just not sure what that [black box] can be. I have seen servo motor breakout boards all the way up to the Masso motor drive controller and I assume that there are all sorts of offerings in between.

If I can get this machine running with just a servo motor breakout board (I see online that @machdrives has a servo motor breakout board), I’d be happy as a clam. If that’s possible, I would have to beg for some guidance as to how to make that controller run my existing Elmo motor drives.

Any thoughts?

Thanks!

[kawfree]

EngineerTex,

I also just purchased a Gerber Sabre 408. I am in the same situation. Gerber Tech told previous owner Servo was bad and gave a list of items that needed to be purchased. Shotgun diagnostics...

What did you decide to to do?

Thanks!

[PCW_MESA]

I have experience with a couple of stepper motor projects, but I’ve never done a thing with servo motors. Now I have to do something with servo motors.

I have a Gerber Sabre 404 CNC woodworking router. It’s got a proprietary drive controller, but off-the-shelf servo motors and motor drives.

The motors are brushed DC motors - GEC Alsthom Parvex Model Number: RX32ER1026
The motor drives are Elmo Model Number: SSA-8/100
Here is the link for the motor drive: http://www.elmomc.com/support/manual...UG_EN_0698.pdf

So here’s the problem: the motor drive controller has issues now and it’s an old machine, so I’m looking at retrofitting the drive controller board. I’m pretty confident that the motors and drives are working, so I want to keep as much as possible.

As I see it, I have the following options:

1) Install a drive controller board that can run the old drives and motors (my preferred option).

2) Install Masso drive controller board and replace drives. There is a user here (@ned_seven) who is doing exactly this project.

3) Install some other brand [what brand?] drive controller board along with new motor drives.

Where I’m unsure is what kind/brand of driver controller board to use to drive the existing motor drives. These old Elmo drives (from the 90’s) have some additional/unknown (to me) interface positions on their terminal blocks. (Link above).

So I think that with servos, there’s something a little more complex than just a stepper motor breakout board between the PC and the motor drives. I’m just not sure what that [black box] can be. I have seen servo motor breakout boards all the way up to the Masso motor drive controller and I assume that there are all sorts of offerings in between.

If I can get this machine running with just a servo motor breakout board (I see online that @machdrives has a servo motor breakout board), I’d be happy as a clam. If that’s possible, I would have to beg for some guidance as to how to make that controller run my existing Elmo motor drives.

Any thoughts?

Thanks!

The drives are standard analog +-10V DC motor drives probably run in velocity mode (if the motors have tachometers)
Its likely that there is quadrature encoder feedback going back to the controller. If you wish to retain the motors and drives
you will need a control solution that can run analog drives.

This is a good application for LinuxCNC and Pico systems or Mesa interface hardware.
LinuxCNC has the advantage over most other retrofit options in that it has full position feedback to the
controller and supports options like homing to index natively.

[EngineerTex]

@PCW_MESA

Well I sure do feel like a jerk here for not at least sending out a thank you for your response. Somehow, I never did see your reply here.

I will read about the LinuxCNC, Pico and Mesa software and hardware. Thank you for getting this information back to me.

[EngineerTex]

EngineerTex,

I also just purchased a Gerber Sabre 408. I am in the same situation. Gerber Tech told previous owner Servo was bad and gave a list of items that needed to be purchased. Shotgun diagnostics...

What did you decide to to do?

Thanks!

Turns out that the problem that I had was with the encoder on the motor. After replacing the motor, my machine began working (to an extent). At this point, it will orient, I can move all three axes and I can do a limited number of things on it, but it is not running programs the way that I would like it to. I'm still trying to figure out what's going on regarding sending a gcode file to the system and how to make that work. It works for a few lines of code and then comes up with an error or two, or it will move to locations that are not in the program.

Regarding the encoder, I verified that it was the motor/encoder combination by swapping the X&Y axis motors. My problem moved from the Y axis to the X axis. I sent the entire motor and encoder to the encoder manufacturer in New Hampshire and had them install the encoder onto the motor and had them test it on their oscilloscope. Came back and worked like a charm. Not cheap, but doubtless cheaper than going through Gerber. Gerber was a nightmare with the diagnostics. Talked to a lady there who absolutely knew nothing besides how to read through a troubleshooting manual. Don't waste your money on that if you can help it.