New control build; PC and hardware

Alright, I've been playing around with LCNC for a bit now and am starting to build a control

I will be retrofitting a machine, most likely a Citizen E32 or something. 6+ axis swiss style turning center. Original control would be a Mitsubishi 300 or 500 series control, AC servos, servo turret indexing, live tooling, rigid tapping all around, full C-axis.

On my Dell Poweredge 2850, running plain old LCNC and no other mods latency/jitter is just silly low... like 1800/3000..... just moving the mouse around. On opening windows it spikes up to 10,000ish... and settles around 4000. Anything that pulls alot of data from the drives slows latency to 10k-20k... but the computer hardly "lags" in the GUI at all.

4 SCSI HDD's are installed and are setup for RAID 5.
2x Xeon ~2.8ghz dual core
8gb DDR2 ECC RAM (2 channels per processor?)
onboard video

I have 3 PCI-X slots @ 133mhz available, but adding a PCI parallel port would slow this down, how can I tell if these are all on the same PCI bus? sudo LSHW?

While, yea it is a server, but I got it, and it does have some sweet data bandwidth and protective features, and shows some OK results thus far.

I was thinking of throwing in
- MESA 5iXX (PCI)
-PCI SATA controller (RAID?) and use a CF card for boot and another drive for running LCNC
-PCI or PCI-X video card to try to pull some video memory usage off of the system

BTW, empty server cases make a great place to mount control hardware! Kinda bulky, but rigid.

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Or, I'll just start over with a MB with a couple of PCIe slots (and buses) for a couple of MESA cards, GPU, and more parallel ports.


For the machine I was planning on using new commercial servos and drives like Yaskawa or Allen Bradley. I also have a lot of Fanuc servos like the Bis-series with 65537 p/rev resolution. kinda a bummer that my AB ultra3000 drives only will let me input 64k p/rev for the motor encoder . BTW the Pico Fanuc serial converter works GREAT!

As far as feedback loops go, I'm planning on keeping speed/torque loops between the servo and drive, and have the drive output an A quad B divided position signal like 5k p/rev to LCNC/MESA card, and output an A quad B back to the drive to follow for position.

Now, these are awesome little motors I would love to use, but there are not alot of generic drives out there that will handle over 64k p/rev
. Would it be worth it to try to divide the encoder signals to the drive with a FPGA board? Or lie to the AB drive and tell it that the motor has half as many poles and encoder res....

Just a little update,

The PE2850 has 3 PCI-X slots to work with. While PCI-X these WILL accept 3.3v compatable PCI cards, like the MESA 5iXX cards. Right now I have a SATA controller, video card, and DB25 card in there.

Which brings me to an even better finding that some of you may like. The onboard SCSI/RAID controller may be disabled and the system will use the PCI SATA controller and boot from there! Ok, so better/newer harddrives is a plus.... A better plus is now when the max jitter WAS around ~50k when torturing, now is much lower after a few hours say ~30k. In other words the server could be usable rather than a space heater. There are still seemingly random spikes in latency I want to pin down but really have not even played with the basic bios settings yet.


Silly question, but does anyone here strip down the OS for LCNC?


Ill know more after more testing and tweeking, but just being able to boot with the onboard SCSI/RAID controller disabled I think is a HUGE plus, and gives this think a better use than a space-heater....