Sabastian Can you (or any others) tutor (Or point to some reference reading) on how the the hardware and firmware of these Mesa boards can provide step pulses "faster" than the parallel port? My simple mind says "the board needs the step commands first, how can it direct the motors if it is still waiting for it's own commands". Is there some other "delay" introduced that allows the difference? Perhaps there is not so much improvement with step and direction applications without feedback? I really have not a clue.
Don't be too technical, I/O signals etc. is not my strength ;-) I've been wondering about this for some time. Thanks in advance Cal Grandy > Hubert Bahr wrote: >> Does HostMot2 work over the usb port? Can I use both Step&Dir and >> encoder modules at the same time? Can we use more than one 7I43 with >> one computer? How does the performance of the system compare between >> HostMot2 and just software generated step and direction? > > HostMot2 does not use the USB port at all - only an EPP parallel port. > > You can use any combination of Step/Dir outputs, PWM outputs, and > Quadrature encoder inputs. For example, the "SVST4_4" firmware for the > 7i43 supports 4 Servos (each servo is one encoder input and one pwm > output) and 4 Steppers (Step/Dir output), plus 16 GPIO pins (for limit > switches etc). You can dynamically disable individual stepgens, > pwmgens, and encoders, and their pins become additional gpios. > > You can have one 7i43 per EPP parallel port, there's no real limit to > how many you can run at a time. Just realize that EPP communication is > quite slow, and it takes something like 100-200 microseconds to service > each 7i43. This is fast compared to emc2's normal 1 KHz servo loop, but > still.... If you need more IO than one 7i43 provides, you should > consider using a 5i20. The cost of one PCI parport board and two 7i43s > is not *that* much less than the cost of one 5i20 (though two 7i43s have > more I/O than one 5i20). > > HostMot2 provides stable step generation independent of any realtime > latency issues the host computer might have. Software step generation > tops out at one step per base period, so maybe 25-50 KHz depending on > your computer. The fastest hm2 stepping that i know if is the Smithy > machines that step at 400 KHz with no problems; the firmware can go way > faster than that. > > > -- > Sebastian Kuzminsky > > ------------------------------------------------------------------------------ > Let Crystal Reports handle the reporting - Free Crystal Reports 2008 > 30-Day > trial. Simplify your report design, integration and deployment - and focus > on > what you do best, core application coding. Discover what's new with > Crystal Reports now. http://p.sf.net/sfu/bobj-july > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
