Jon Elson wrote: > Karl Schmidt wrote: >> There seems to be a limit as to how fast one can drive a printer port for >> stepper control. Has >> anyone thought of making a PCI-E board for very high-speed I/O? Just where >> is the bottle neck? >> > The port, itself, is not the bottleneck. I use the printer port for EPP > transfers to a controller board. The typical motherboard PP can > transfer a byte every 800 ns with handshaking, a regular PCI port can > get down to 600 ns. The hangup is that software that would send fast > step pulses would completely take over the CPU. For faster step pulse > rates, say much over 50 KHz, an external step generator is what you > want. There are several of these, some work over the parallel port, or > PCI slot. PCI-E is not really much faster that PCI unless you go to > multi-lane versions. > > So, my Universal Stepper Controller is conservatively designed to go up > to 300,000 steps/second on up to 4 axes simultaneously. (Two boards can > be chained for up to 8 axes.) EMC sends a velocity command to the > board, it puts out step pulses and also counts the pulses issued (or > optionally counts position from an encoder). EMC reads the position > 1000 times a second and updates the commanded velocity. > > Jon
Interesting - I'm thinking about the idea of doing EMC with one of those Chinese laser cutters - the mirrors have to move very fast without hickups for engraving. Do you have a resource list of these step generators you can point me to? -------------------------------------------------------------------------------- Karl Schmidt EMail [email protected] Transtronics, Inc. WEB http://xtronics.com 3209 West 9th Street Ph (785) 841-3089 Lawrence, KS 66049 FAX (785) 841-0434 From NPR - National Propaganda Radio we get the following: One Side Considered or All Things Distorted -------------------------------------------------------------------------------- ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
