Lathe controller

Hi I am in the planing stages of building a lathe:
2 axis with turret (8 or 12 stations) 6 Gear ratios and a VFD (closed loop steppers)
an MPG is a must.
This lathe should be able to thread (spindle encoding)
Most people so far suggested to go to linuxcnc.
I have 2 mills running on Mach3 and I did build the controller (LPT)
So I am not a complete newbie to the world of CNC.
But the question is what hardware should I get.
Especially if I go with Mesa cards.
There are like a million options.
the 5i25 7i76 plug and go kits seem fairly popular.
but there is also the 7i76e which seems to me like the complete plug and go package
but there are so many cards and they are so difficult to compare.
I haven't found a table comparing there features anywhere.

I am very gratefull for your input.

From my current mills I know a LPT port is rather limited with IOs
with a lathe having a turret I would already max out all IOs
turret needs step dir sensor for locked and positions
limit and home switches So I pretty much get over the limit of one LPT. with an MPG I would max out almost two.
and I heard that driving a VFD over LPT makes quite a few problems.
for threading I need some speed. I calculated that with 120khz I have more than enough. But I wouldn't dream of pressing that through an LPT cable.
I think the LPT is useful to have as additional IOs (if the board has a chargepump)

thank you. I have never heard of those two. Since I live in Germany the supply of the hardware you mentioned isn't very good. Mesa is not good either but at least I know one supplier.
Is there any diffrence between a plug n go 5i25 with an 7i76 and an 7i76e?
As far as I know the ethernet port wasn't supported by linux cnc (at least not the smoothstepper and Pokeys (Ethernet))
Is there an advantage in using the 5i25 a big cable and the 7i76? (they are roughly the same price as the 7i76e)
if one uses the 7i76e will it connect to my hub and than to the pc? or do I need a direct connection?

andypugh wrote:

You should also consider[1]
www.pico-systems.com/univstep.html

Thanks, Andy!

Yes, the Pico Systems Universal Stepper Controller might be a good fit. It puts everything in one unit. So, you have E-stop plus 15 general-purpose inputs, 8 solid state relay positions, 4 encoder counters and 4 step generators. Encoder counters that are not associated with a step generator can be used for the spindle encoder and MPG. An add-on board can produce analog 0 - +10 V (or -10 to +10) to control the spindle drive. I'm not sure if the 15 GP inputs are enough for all the features on the lathe.

Jon

OK, I got now quite a few options. I really like the 7i76e so far due to the tiny ethernet capble and the option to expand it if needed.
2MPGs sounds perfect for a lathe. 1 spindle encoder sounds good. Eventhough I would prefer a second.
Is there any disadvantage to using the preempt-RT kernel other than that there is no live cd?

I am planning to use the leadshine closed loop steppers. (So it is within the stepper driver ensemble)
Yes Yes the turret needs one in my opinion to make sure the locking positions are reached before the lock is enabled.
"Absolute latency isn't quite as good, but that only matters with software-stepping. With external step-generators it's not so critical." What does that mean exactly? Will I be stuck at 20 khz stepping frequency? Or Will I move from (I got no Idea what the Mesa cards can actually do) 300Mhz to 298MHz stepping frequency
From my calculation 120khz would give me quite some room.