Dc servo motor control

There are 4 or 5 similar machines already working with LinuXCNC daily:
forum.linuxcnc.org/show-your-stuff/34986...nuxcnc-and-proma-thc

forum.linuxcnc.org/38-general-linuxcnc-q...rade-project?start=0

You could also look at the Pico PPMC (which requires a parallel port, though used as a communications bus rather than bit-banging pins)

The answer will depend on whether you still have the DC servo drives, though.

Picture with those green round things, that is the servo drive.

tommylight wrote:

Picture with those green round things, that is the servo drive.

Ah, yes. I overlooked that. 

I guess the question then becomes whether they work or not.

I guess that they are analogue-voltage controlled velocity-mode servos? I am confused by the second photo, is that stacked motors or a very large tachometer? 
 

andypugh wrote:

I guess that they are analogue-voltage controlled velocity-mode servos?

Yes they are.

andypugh wrote:

I am confused by the second photo, is that stacked motors or a very large tachometer?

Those are very small motors! So the tacho and encoder look huge on them. Outer diameter difference between motor and tacho/encoder lid is about 2 CM.

To answer the original question, a common choice for a DC servo machine is the 5i25/6i25 PCI/PCIe card and a 7i77.

Alternatively the 7i97 is am ethernet-interfaced all-in-one for around the same price.

Both may be somewhat overkill for this application.

An alternative would be to use cards from the the 50-pin header card family[1], with a 5i24 or 7i93 and the 7i33TA (but then you would probably need another breakout for GPIO)

[1] There are two main families of Mesa cards. Some use a 50-pin header, and these go back to the 5i20 which was the first to be supported by LinuxCNC. Then the 5i25 came along as a "souped-up" parallel port with a DB25 connector.
Then, on top of that, there are all the smart-serial interfaced daughter cards, which hook together with CAT5 cables.