Re: [CAD_CAM_EDM_DRO] Bridgeport CNC Mill???

David G. LeVine wrote:

>
> Assuming the encoders are good (that would be the second thing I would
> check), EMC2 has built in support for the servos. Admittedly, the 1 mS
> update rate is not as fast as it might be, but the cost to try out is
> pretty low. See http://www.linuxcnc.org/ for details.
>

Why would 1 KHz be a problem? Maybe for routers or high-speed machining
centers
running over 400 IPM, but on the typical Bridgeport the errors from a 1
KHz servo
loop will be quite small. And, of course, if that actually IS too slow,
you can turn up
the rate. 5 KHz is easy, 10 KHz or more can be achieved with some hardware.
Velocity servos do most of the control in the servo amps, so having
position updates
every millisecond should be fine. Do you really need a servo bandwidth
of 500 Hz on
a 300 Lb. piece of iron?

I don't know what the servo loop rate is on the original controller, but
it likely is
no more than 1 KHz.

Jon