So far so good. It looks like the dspmc will shape up to be all that it promisses. I think this will be THE servo controller to use with Mach. I don't have the io hooked up yet but i have the control and break out boards installed and the encoders and amps hooked up so I can make motion. I have my A-M-C amps tuned in voltage mode so I am running what is called a position over voltage loop--meaning my amps are running a voltage loop and the dspmc is running a position loop over that. The following is a repost from my showntell thread on my spindle wizard for the benefit of others using the dspmc or considering using it. I personally think my machine is the "***balls***" mechanically/electrically so it will let the dspmc shine. My encoders are 1000 line quadrature encoders so 4000 counts per rev and my ballscrews are 5tpi so that's 20,000 counts per inch. With my motors and power supply I should max at about 190 ipm so I am tuning at 150 ipm to be aggressive but avoid clipping by either the amps or control DACs.
Controller's PID tuning:
At first I tried a bunch of different tuning methods where you adjust one parameter at a time and wasn't having much luck. Then I tried a method where you set both p and d at the same time in a ratio determined by the pid loop sample rate. The DSPMC/IP has a 5kHz sample rate which means the D should be 25 times the P--then if your amps are in current mode you probably have to turn up d but as you will see I didn't have to. I have my scale set to 100. This will allow me to have a small integer I--I will probably barely need any I at all.
First iteration I tried
P=100
D=2500
There was no motion on the first try to I multiplied by 10
Second iteration I tried
P=1000
D=25000
.....oops, I forgot to save that screenshot
There was very sluggish motion so I multiplied by 2
3rd iteration I tried
p=2000
d=50000
The motion was much better but still sluggish so I multiplied by 2 again
4th iteration I tried
p=4000
d=100,000
motion was excellent so I tested larger moves
Vital systems is still working on the axisworks software. That's an alpha I'm working on now. I asked Rufi/Abdul to add check boxes allow traces to be added for position error, commanded velocity, and commanded acceleration and to remove the commanded position and actual position. When he has that done it will be easy to Dial in the feed forwards which I want to do before even bothering with throwing an I in the pid loop.
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