I just can't seem to put this thing down at the moment, which I suppose is good. Though I'm determined to run a real job on the Hardinge this w/e.
Todays work has made that more practical. Yet another pcb made, this one interfaces with the PLC and also takes the DIYCNC Spindle2 board (Step/dir to Voltage converter) as a piggyback board. I haven't taken a picture yet as it's all still strewn over the floor in a test setup! But it all works, and I now have software control over the spindle.
I found that although the Siemens MM440 VFD I'm using as a spindle drive was all ok operated from it's keypad, but under analogue control I could ony get speeds upto 50Hz. A quick delve into the VAST manuals suggested the ADC input required scaling, and there are several parameters involved! After a lot of fiddling I have speeds upto 4000rpm and fairly linear. Linearity I will tune some more later. Upto about 1800 rpm it's always within about 10 rpm of commanded, but gains slightly at higher speeds, although always within 100 rpm.
Wayne.....