At the moment I still have the stepgen 5 on the second parallel port so I can measure both PWM and STEPPING.
Raspberry Pi4 + 1GB + LinuxCNC + MESA_7i92H + ProbotixBoB + custom VHDL for the MESA board thanks to Peter Wallace at MESA. AXIS display shows 1500 RPM, PWM is 50% and if I zoom in on the step pulses my scope tells me it's 250kHz which is 50% of the max step rate as currently set. Math for that is 2500 line encoder = 10,000 edges per revolution which at 3000 RPM is 50 RPS. And 50 x 10,000 = 500Khz step rate. The encoder on the spindle will have less lines and likely I'll program the Bergerda Servo to divide the encoder by 5 to bring my step rate for the spindle down to 100kHz. It's differential drive out to the Bergerda so I'm not too worried about noise. Power tapping here I come. Baby steps. John > -----Original Message----- > From: John Dammeyer [mailto:[email protected]] > Sent: June-13-21 1:35 AM > To: 'Enhanced Machine Controller (EMC)' > Subject: Re: [Emc-users] Spindle control > > So here's the photo with the Pi4 1GB running LinuxCNC. The 4 roller switches > are the three homes and the shared limit for the other > axis. Normally there would be 3 in series. The orange paddle switch is > estop. The cable to these switches goes to the 7i92H > P2.DB25. > > On the P1 connector I have the Probotix BoB. No isolation needed for testing > so it's powered from the same supply on both sides. I > have the scope on Pins 2,3 of what would be the second DB25. > > Now if I plug a motor into the step/dir outputs of the BoB it should spin the > motor based on requested spindle RPM. > > Been a good day. > John > > > -----Original Message----- > > From: John Dammeyer [mailto:[email protected]] > > Sent: June-13-21 1:05 AM > > To: 'Enhanced Machine Controller (EMC)' > > Subject: Re: [Emc-users] Spindle control > > > > No worries. Found the solution. > > I have spindle.0.speed-out-rps connected to spindle-cmd which ends up > > being a signed float. > > > > net spindle-cmd <= spindle.0.speed-out-rps > > > > And that's connected to the stepgen > > net spindle-cmd => hm2_7i92.0.stepgen.05.velocity-cmd > > > > Results in my P1.19_DB25.2 showing a square wave on the scope when I toggle > > the axis CW and click on the speed. Change to > CCW > > and click speed again I get the square wave on the scope and the > > P1.23_DB25.3 changes to a logic high for a change in direction. > > > > More when I test it with a motor. > > John > > > >
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