alan wrote: > So any suggestions for a cheap replacement computer. What is the > smallest, cheapest desktop or laptop with a parallel port? I thought > about using a pc/104 card but again here in the UK they seem to be quite > expensive? Has anyone got experience using pc/104 ? > Stuart Stevenson put me onto the Gateway Profile 3, which is basically a laptop MoBo and screen in a pedestal-mount case, with separate keyboard. it has one parallel port, USB and network. it has a cardbus slot, but so far I have not been able to get that to work for a second parallel port. These go fairly cheap on eBay. 1 GHz CPU, 256 MB on many of them. Perfectly adequate for EMC2. So, if a single parport is good enough, then it is one option.
Dell has some boxes that are the size of a brick, with hard drive, mobo, parallel port, etc. in them. I don't remember the model number. You would need a keyboard, mouse and video screen for these. > So really my query is also about the future. Where will emc go if > parallel ports become a thing of the past? > > Yeah...... At least with larger desktops, you can still plug a parallel port into the PCI or PCIe slots. I still think there may be a hope for USB. I have gotten a USB target board the size of a large postage stamp for some digital control retrofits at work. This is not real time stuff, however. But, if the USB clock were to be made to trigger the periodic interrupts that schedule EMC, then it may be possible to control servo systems over USB. High speed mode has "micro-frames", allowing up to 8 transactions per millisecond. That might allow 2 servo updates per ms, allowing for compute time. (Maybe even 8 if you allow read/compute/write to lag one microframe.) Another possible scheme would be to use any machine that had 2 network ports. One for machine control, one for regular network. (You could even do it with just one net port, but you'd have to keep the local network driver from messing with the port when EMC was using it.) 100 mb Ethernet should provide VERY good servo update times. Jon ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
