I must be a complete idiot because I can't. I have Mach neatly switching the KB power on & off via M3 commands or clicking the onscreen "spindle" button. If I leave the manual pot connected, the KB varies the speed of the Baldor 3/4 hp motor beautifully (yay KB!) If I take off the pot & connect the C11 to the KB, the motor instantly spins up to a much higher top speed with no control via "S" commands. No Mach config changes make any difference.
The C11 manual (to me) is vague but the C6/KB hookup section has more verbage on hooking up to a KB and I assume the 0-10V analog circuits are the same in the 2 boards. My interpretation of the C11 instructions is that the pot is to be removed and the C11 0-10V analog outputs connect to the P1 & P2 terminals on the KB which leaves the P3 terminal open. The C6 instructions (pasted below) to me imply that the outputs are connected to the pot terminals. Can that be true???
"These are the steps for replacing a potentiometer:
1. Measure the voltage difference between P1 and P3. Make sure it measures
under +12vdc.
2. Fine tune the analog output to the output voltage you got from step 1.
3. Connect the ground from the analog output to the ground of the
potentiometer (P1).
4. Connect the analog output to the wiper connection of the potentiometer
(P2).
If the reference voltage from pot is between +10 and 12vdc, you can use it to
power the analog circuit (not for the C6, because the relays might draw too much
power). In this case, connect P1 to the ground of the power terminal, and P3 to the
+12vdc power connector."
I checked the voltage across the KB P1/P2 terminals with the pot attached & turned up to max, motor running at full chat and get 3.5VDC. I checked the voltage at the gnd/0-10V outputs on the C11 (with nothing attached) and it varies up & down in concert with varying S commands from Mach. I set it to 3.5V max with the onboard trim pot. I know, not what the inst says but I had to try something to slow things down!
When the pot is removed from the KB and the 2 leads are connected from the C11, the voltage across P1 & P2 is locked on approx 6.5 volts, no matter what is commanded by Mach.
Somebody please smack me up side d'head and clear up my stoopidness!!