On Sunday 09 June 2013 19:23:06 Jon Elson did opine: > On 9 June 2013 23:05, Gene Heskett <[email protected]> wrote: > >> However, with the motor driver disconnected so there is no input from > >> the encoder, the output voltage steps at the C41 output aren't truly > >> linear either. > > Do you know that the C41 is completely linear? From what little I know > about it, > I would not be surprised if it is somewhat nonlinear. > > Jon > Somewhat? +1 for QOTW, Jon
Looking at its voltage output, with the motor disabled so there is no feedback,off = 0.125 volts click fwd button= 0.382 diff = 0.257 click + button = 0.942 diff = 0.560 click + again = 1.584 diff = 0.642 click + again = 2.302 diff = 0.718 click + again = 3.094 diff = 0.792 click + again = 3.970 diff = 0.876 click + again = 4.940 diff = 0.970 click + again = 6.04 diff = 1.100 click + again = 7.33 diff = 1.29 click + again = 8.88 diff = 1.55 click + again = 9.90 diff = 1.02 and the output opamp on the C41 is saturated, spindle tach pinned at 1200. Probably too much for the motor on a long term basis as its doing around 9 to 10 grand at the armature. Lots of moving air noise from its fan/pulley combination. In order to get the zero speed safety lockout to work, I had to raise a resistor on the C41's output pullup to get it to go low enough to reset that controllers lockout, it would not function when the resting pwm off voltage was in the .257 range. A 2.7k resistor got raised to 12k. Now, back to your regularly scheduled Sunday evening cookout after you've stopped laughing at the above data. Gruesome ain't it... :) I wish I could find the schematic for a electronic tachometer I had on a 52 Chryslers 331 hemi 40 years ago, that charge pump circuit was within 1% of dead linear, based on counting pulses from the ignition points. I also miss that car, with a 3 spd od tranny where the fluid drive once was, 30 mph/1000 rpm, 21 miles to the gallon at 99 mph the length of South Dakota on one tank of gas in the middle of the night. The tach just sat there at 3300 about 90% of the time. That hemi could sing bass with authority, or teach the chevies how to sing soprano if it had to. And even with a straight pipe under the rear axle, it never got me a noise ticket. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> is up! My views <http://www.armchairpatriot.com/What%20Has%20America%20Become.shtml> Too much is just enough. -- Mark Twain, on whiskey A pen in the hand of this president is far more dangerous than 200 million guns in the hands of law-abiding citizens. ------------------------------------------------------------------------------ How ServiceNow helps IT people transform IT departments: 1. A cloud service to automate IT design, transition and operations 2. Dashboards that offer high-level views of enterprise services 3. A single system of record for all IT processes http://p.sf.net/sfu/servicenow-d2d-j _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
