On May 23, 2012, at 8:45 PM, Jon Elson wrote: > I think a very simple circuit, largely analog plus some one > shots and > a logic gate could do it. Probably 3 chips per axis. Some RC feeding an > opto-coupler, a 74HC123 and a gate package. If the output to the motor > exceeds some value (maybe 5 V) for some short time, and there are no > pulses on BOTH encoder signals, that is a fault, and it trips the E-stop. > Parts cost should be about $3 per axis, in single quantities.
Hi Jon, Sounds perfect! Sign me up! ;) Would you be interested in designing and building me a few? Just let me know what it might cost (on or off list is fine with me). I don't mind paying to develop it and you could open source the schematic or keep it to yourself. The only other solution (more of a work-around really) I have been able to think of is before I power on the servo PSU check to make sure the DRO is working, then power on. Then when the machine is on, the HAL settings provided by Andy would detect if a encoder goes offline while running. Certainly not as ideal as a automated install and forget system in place, but not a overly painful startup process either. Best, Jeshua Lacock Founder/Engineer 3DTOPO Incorporated <http://3DTOPO.com> Phone: 208.462.4171 ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
