View Full Version : Need help with analog spindle control on C11G
08-16-2009, 12:00 AM
I'm finally getting the last bits of my Boss 5 retrofit up and running. So far the only thing that's not working/making sense is the spindle control. I can't seem to get any variable voltage out of the CNC4PC C11G Analog terminals. I have a 13.56V external source (12V wall wart, 900ma) connected to the external power source terminals next to the analog terminals. I'm running Mach for the control program. Spindle is enabled per Arturo's docs, step set to pin 14, Steps per to 2000 and velocity to 1500. All I ever get for a voltage is 0.699V. I've tried active low, active high. No luck. It's probably something basic I'm missing. Any suggestions are very welcome.
08-16-2009, 08:04 AM
Try running at 5 step pulse width on the motor tuning page.
Also under ports and pins > spindle setup have you got Use motor spindle output and step / dir motor ticked ?
08-16-2009, 08:59 PM
The step and dir boxes are checked. I can hear the electromechanical relay for pin 16 (open for forward, closed for reverse per the TB Woods Se1 VFD with parameter 19 set to 4). So I must be close. If I could get a voltage other than 0.661V out of the analog speed control I'd be very happy.
I did get the drives tuned on all the axes, and am getting rapids of 120 ipm. Not bad for the old girl with the original motors. I fell back on manually starting the spindle and managed to cut a circular pocket, so I made my first CNC chips today! And snapped a 1/2" end mill by jogging into the vise. Does that qualify as my first crash? Anyhow, after three years of gathering bits and pieces -- IT'S ALIVE!
08-17-2009, 04:13 AM
If you tell Mach to run at S500 the LED on pin 14 should glow as the speed is commanded higher S 1,000 S2,000 etc the light should glow brighter, is that happening ?
08-17-2009, 06:23 PM
That's what's happening. If I drop the speed down, the LED gets dimmer. Still no change in the voltage. I'm using a Fluke 77 to measure. I pushed down on all the DIP chips to ensure they're seated. I'm starting to think there's something wrong with the board. I can take some screen captures if it would help troubleshooting.
08-17-2009, 06:30 PM
Sounds a bit that way, is the pot to the right of the 0 -10 volt terminal strip fully clockwise ?
Are you taking these readings with the VFD disconnected ?
08-17-2009, 09:36 PM
I've tried with the pot to the max (fully CW, and full CCM, and most positions in between), and no, the VFD is not connected. On the bright side, the LM2907N is only $2 from Digikey...hopefully that would be the fix.
08-18-2009, 10:46 AM
I chatted with Arturo Duncan and he agreed it's probably a hardware issue. A set of replacement chips are on their way.
Thank you John, for all your assistance!