I measured the voltages across the potentiometers on both my X2 and X3 they are both Harbor Freight machines. The X2 about 15 months old and the X3 about 6 months old. The X2 had 12 volts on P1, varying proportional to increasing speed on P2 relative to P3. The X3 had 7 volts on P3, varying proportional to increasing speed on P2 relative to P1. So both look like they can be controlled by the VFD outputs of the Gecko G540. Other output pins can be used to control the direction and power through relays. I am thinking that I might use the power relay to also switch control from Manual to computer so I will want multiple contacts or multiple relays working in parallel. This should not be high duty cycle so standard coil and contacts should work. I think I will leave the power switch in series with the new power relay so it can be shutdown either place and the Manual switch must be engaged before the computer can control the machine. I have never used solid state relays, they sound interesting for higher number of switching cycles, but that would be expensive to implement the cross switching, is it worth it. I still need to research what I am going to do about estop. I need to see how it is currently wired on each machine.
Now for the feedback. What do you recommend to feed back the speed? I would think that multiple pulses per revolution would aid faster response. However, a single pulse per revolution would also serve as a sync point for rigid tapping. Is this similar in character to the recent discussion on threading? Which way is better, or do I need both.? If multiple pulses, do they need to be 50 percent duty cycle? I was thinking along the lines of an opto-interrupter reading cutouts on a disk attached to the spindle pulley. I am looking to sync to speeds over a range roughly from 50 to 6000 rpm. Thanks Hubert ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
