On Wednesday 14 April 2021 23:15:56 andrew beck wrote: > Hey guys > > looking for info on how to wire up a mesa ency encoder card to my vfd. > > I have a encoder card that outputs 12v to the encoder that I have > (which is also a 12 v encoder) but would like to split the encoder > pulses off to my 7i77 as well as back to schiender altivar 71 vfd. > > the vfd does output the encoder pulses but won't output the z pulse so > I am thinking of using the ENCY card to allow me to tap in to signals. > > couple of questions > > 1 does the ency card handle 12v > > 2 what is the best way to wire it up. I have a standard quad encoder > but with push pull outputs > > regards > > Andrew
You are not teling us if the encoder you have is an A/B/Z encoder Some where, if you want well behaved systems, you MUST have an index signal, preferably one related to the spindle on a 1 to 1 basis. If you want to do threading, you must make this so. When I decided my optical encoder just plain had too much quantization noise to do a good job, the next most obvious place to put a higher resolution encoder was not on my milling machines spindle but on he spindle motor by drilling and tapping the rear of the shaft and making an extension to it to drive the encoder, which I bought on ebay for a $20 bill. A 1024 line encoder. But when it arrived, it was a differential output and the mesa card I was using at the time was a TTL input, but $4 worth of rs485 to translate the differential into a single ended TTL fixed that right up. But that left me without a spindle inedx, the Z in this equation. So I gooped a screw to the side of the drawbar cap in the mill, and put an ATS-667 hall effect to watch it pass by once per revolution of the spindle. So that gave me an index. But what to use for a scale, and what do I do about the fact that the G0704 has a two speed head And the working scale, due to the gear ratios in the head, is a 4 or 5 digit number depending on the gear its in. Developing the two scale factors I needed was a matter of hooking up a counter to one leg of the encoder, and some hal logic to record the counter at turn 3, run it to 103, then subracting the counter reading at turn 3 from the counter reading at turn 103, and dividing that by 100, giving the needed scale ratios. Some more hal trickery to complete that based on 2 switches I put on the gear shift knob that tells hal when it is fully engaged and which gear its in. An added bonus for when its not fully in gear is that I keep the motor running at about 20 rpm when it not in gear, and the servo response is milliseconds, I can be singing at 3000 revs, reach up and turn the gearshift knob, the first 2 degrees of it slows the motor to a crawl, and the other gears teeth engage silently because they ae moving so slow, and when its finally fully engaged, the other switch reapplies the motors requested speed, and 30 milliseconds later the tach says 1500 revs. Or vice-versa. Because the quantization noise is reduced by a factor of several hundred by the much higher encoder resolution, the servo no longer rattles the head gears, making a sound like the bearing balls are square, and runs dead silent now. Anyone who wants to know how I did that is welcome to PM me asking for the ini and hal files that make it happen. The same basic solution can do what you want to do Andrew. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
