Partial retrofit of an Omniturn

Greetings programs!
I'm helping out a buddy of mine, he's got an old Omniturn, that aside from the internal PC/MC2 card, it functional. It uses a closed loop servo setup, 2-axis, collet control, and VFD for spindle.
We're considering either replacing everything with a stepper/open loops system, or looking at the feasibility of using the servo/encoder/servo amps that are on the machine now, and installing an updated computer and interface system, using LinuxCNC.
I believe Mesa has the parts we need, from what I've been able to piece together so far, a 5i25, and a 7i77 will get me part way there. It looks like I should be able to control the Spindle VFD from the 7i77, as well as the collet closer.
Am I missing something? The machine has AMC 25A8 servo amps in it, If I'm understanding everthing correctly, the 7i77 should be fine with these.
I freely admit to being a newbie at this CNC stuff, and a closed-loops system isn't an easy way to start out, but we'd like to utilize most of what he already has.

Feel free to toss out your ideas or slap me down!

Thanks!

Ron

If the servos work fine keep them.
What are the feedback devices from the motors - I think encoders are very common on AMC amps.
Does it have linear scales too?
AMC amps are a good fit for linuxcnc.
The 5i25/7i77 is appropriate for a servo system.
If you require more I/O then the 7i77 has on it then you can add a daughter card easily.
If the VFD supports serial communication that might be convenient - depends on what branch/model.

Sounds like a good project that will follow the 'common road' route of interfacing to linuxcnc.

Thanks for the replies guys... If the original Omniturn MC2 card is toast and can't be fixed, LinuxCNC/Mesa being used with the existing amps and servo motors is STRONGLY leading my thinking!
I'm almost positive the two axis motors have encoders, but I'll verify that tomorrow.
The only things I need the Mesa board to control are 2 Axis, VFD for Spindle, Collet closer, and coolant pump. That's it as far as I know. I do get new things sprung on me regularly, but I expect that now!
Pretty stoked about doing this... Should be a fairly straightforward upgrade, but am expecting twists and turns in the road ahead!

Wow, talk about life getting in the way!! Sad to say though, this doesn't hold the record for longest sidetrack I've experienced!!

I'm finally getting back to this project. I did learn that the MC2 card is DOA with no chance of repair.
We already have a good modern computer, and from the testing that's been done, it appears that the AMC 25A8 Servo drivers
survived. I have an email in to Viper and Mesa to inquire about their recommendations.
Hopefully I'll hear back from at least one of them soon!

Ron

andypugh wrote:

AZ_Ron wrote:

, it appears that the AMC 25A8 Servo drivers
survived.

Those are analog input drives, so this looks like a typical job for the 5i25 / 7i77 combination.
If you have a parallel port then the Pico PPMC might be worth a look too. (it just happens to use the parallel port as a communications bus, don't compare it to the typical parport/stepper cludge.

Yes, the Pico Systems PPMC boards, for analog velocity servos, would also be a good fit for this.

Jon