Re: [CAD_CAM_EDM_DRO] CNC Controler Software

archie5594 wrote:

>Hello All,
>
>I've got a question. I'm currently investigating which controller
>software to use. Right now I've been trying out TurboCNC. So far I
>like it just fine. However, I've noticed some software, like
>FlashCut, requires a 'Signal Generator'. Why would someone need a
>signal generator? I know it generates step and direction signals,
>but can't the software do this also. I've read that the signal
>generators offer true real-time signals, but again, what's the
>benifit of that. What really got me going was the price tag for
>FlashCut. I can see that the software is loaded with features, and
>has a very nice interface, but is the signal generator what really
>bring so much to the table? (i.e. $1095 price tag!)
>
>

Software-only solutions have two related problems. One is the absolute
upper
limit of step pulses per second, somewhat proportional to CPU speed and the
techniques used to time out the pulses. The second is that as the pulse
rate
approaches the upper limit, the granularity of the step timing becomes
rougher.
At some point, the jumps in speed become so great that the motor can't
respond,
and it stalls. EMC has a limit of about 25,000 steps/second, Mach2 is
about 40,000.
These are approximate, as some motor/driver combinations can tolerate the
rough timing better than others.

With my Universal Stepper Controller, for instance, I can go up to
300,000 steps
per second, and the granularity is always 100 nS. Even at the maximum
rate, the
change in rate is still only a 3% jump.

That is what hardware can buy you. Now, if you are running a huge
machine with a full-step
driver and low speeds, software can do all you want. But, if you are
running a CNC
router with microstepping drives, the software limits can be a problem.

Jon