newbe questions?

hi,

sorry if this post is duplicated, come back first attempt with an error

Question 1:
ok my drivers, pacificscientific M6410's have step rate at 250uS max and direction valid for 50uS. How'd I input these since I can't find step space in the manual and my address valid is specified as an electrical signal at the direction opto coupler, so I don't know what the setup time is, was thinking of the following:

step time 250uS
step space: ??? unknown
direction hold: 50uS
direction setup 1uS (only because I don't want to leave it zero)


Question 2:
My new laptop has an expresscard parallel port adapter based on Oxford Semiconductors 952 chip.

"dmesg | grep par" shows:

...
[ 9.503889] parport_pc 0000:0d:00.0: PCI INT A -> GSI 19 (level, low) -> IRQ 19
[ 9.503894] PCI parallel port detected: 1415:c000, I/O at 0xdff8(0xdff4), IRQ 19
[ 9.504187] parport0: PC-style at 0xdff8 (0xdff4), irq 19, using FIFO [PCSPP,TRISTATE,COMPAT,EPP,ECP]
[ 9.588403] ppdev: user-space parallel port driver
[ 9.649676] lp0: using parport0 (interrupt-driven).
...

NOTE: I seem to be able to config. the h/w with their Vista Driver and reboot into linux with those settings, i.e. no interrupt support if wanted but I can't seem to change the resources.

So is my lpt address 0xdff8? and is this gonna work seeing as my old laptop running DOS and other *coff* s/w used 378.

Question 3:
My new laptop a dell 1735, 3GB ram, dual core T????, seems to fail the latency tests miserably - getting like into the mS when dragging google maps, sat images view around. I tried the grub kernal boot switches, like "nousb" and "iso1cpu" or whatever and they improved it but still basically crud when running lots of stuff.

The thing is, I installed this ubuntu 10.04 linuxcnc into a small patition, not wanting to use it for anything but machine control, when i want to use GIMP or some dev. enviroment I'll reboot into Nutty 11.04. So why bother over loading the CPU when all I'm gonna run is linuxcnc on this build? If I just run linuxcnc I could probably get away with around 60uS jitter going by the latency test, will this do?

What happens if jitter larger than my config. occurs, I mean does my machine miss steps or simply move slower not meeting my step/spindle speed settings. Last thing I want is to go 0,0 and have the machine loose step and not line up after running a long script?

Oh, my new cnc table is a shopbot PRT clone with standard steppers, so any other configurations for such a machine would be gratefully received

Thanks

giggler

You might want to look here...

wiki.linuxcnc.org/emcinfo.pl?Hardware_Requirements

Laptops can have some problems.

and

wiki.linuxcnc.org/emcinfo.pl?TroubleShooting

and

wiki.linuxcnc.org/emcinfo.pl?TweakingSoftwareStepGeneration

Take a look at your video driver options.

Rick G

Thanks Rick.

My parallel port seems to work but I can't find an answer to my question about jitter - will it lose step or just move out of time or something else if I can't meet the jitter requirements.

Cheers,

giggler

My parallel port seems to work but I can't find an answer to my question about jitter - will it lose step or just move out of time or something else if I can't meet the jitter requirements.

I guess the big question is what kind of latency numbers are you coming up with?

If they are not terrible depending on your set up (gear ratio, micro step etc.) you may be OK as long as you do not exceed them. Find the numbers run stepconf with your info and it will calculate what speed you can run.

And yes bad things can happen if you exceed them.

Rick G