Re: Re: EHP.. Any comments on micro Throughput

James Eckman wrote:

> > I was thinking that someone would show me that high math throughput
> is not
> > required. I know old time CNC had 8080 CPU's and it did this stuff.

Yes, but old CNC systems had poor bandwidth, some had high following
errors, and some had terrible block processing rates (4/sec or worse).
I started with an Allen-Bradley 7320 (1978 vintage, 16-bit minicomputer
with math processing unit). It had a 100 Hz servo update rate, and
plain
P loop, only. It had a bandwidth of darn near 2 Hz. It was pretty
pitiful,
even on a Bridgeport. Maybe on a gargantuan 50 foot bed mill, it was
fast enough, but it would have been a bottleneck on anything that
required
profiling with the slow block rate.

EMC is running on my machine at 1000 Hz servo update rate, about 400 Hz
servo bandwidth, PID + feedforward on the loop computations, and a
block processing rate of about 20/sec, all that on a 100 MHz Pentium.

Jon