Rick Calder wrote: > No, neither. I have made a few tachometers using Atmel microcontrollers. The > sensor, either a hall effect or optical, just sends pulses and the > microcontroller counts them up and handles the display. Another one I made > had > counter chips and the microcontroller basically just handled the display part. > > I would like emc2 to do the counting and display. It seems simple enough, I > just haven't found anything in the docs that describes it. > The EMC encoder HAL component has an option to count pulses from a single signal (as opposed to a standard encoder with two signals in quadrature). The problem is that a low-res pulse (like once per rev) produces very few counts per servo cycle. So, this will provide a very coarse speed indication. You can then feed this through a low pass filter to smooth the output. It may be the velocity estimation scheme with last pulse timestamps will help this greatly.
Add this line to your .ini file : POSTGUI_HALFILE = spindle.hal The file spindle.hal should be in the same directory with the .ini file, and contain this line : linksp SpindleRPM pyvcp.SpindleRPM In your hal file, you should add something derived from this : loadrt mult2 count=1 addf mult2.1 servo-thread loadrt encoder num_chan=1 addf encoder.update-counters servo-thread addf encoder.capture-position servo-thread # spindle speed display setp encoder.0.counter-mode 1 net sensor <your.digital-input.here> encoder.0.phase-A net spinraw encoder.0.velocity mult2.0.in0 setp mult2.0.in1 185.185185 # (60/encoder count/rev) newsig SpindleRPM float linkps mult2.0.out => SpindleRPM Then, the velocity output of the encoder module would feed the signal spinraw. The constant 185.185.... is the conversion factor to convert pulses per millisecond to RPM for my particular encoder. In your case, if it is one pulse per rev, the factor would be just 60.0 Jon ------------------------------------------------------------------------------ This SF.net email is sponsored by Make an app they can't live without Enter the BlackBerry Developer Challenge http://p.sf.net/sfu/RIM-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
