Re: [CAD_CAM_EDM_DRO] Re: emc help

Greg wrote:

>Hello,
>I had already planned on settng an external plc to acount for emc's
>dismall i/o control.
>My estop circuit is already integrated,thru a watchdog,drives,etc.
>Having a 10 volt command while your computer is hung would be a bad
>situation.(can you say crash)
>Since you seem to be knowledgable about emc
>What is emc's top feed rate given a .0001 resoultion from the encoders
>(with a 2ghz computer)
>

Are we talking about an analog servo system? There is no top feed rate,
other than whatever velocity you have set 10 V equal to. There probably
are practical limits on the numbers you can enter for F, but I'll bet it
will take 999, probably 9999! In the ini file, you set a maximum feedrate,
and that is assumed to equal 10 V on the DAC. Assuming no position
error is seen on the encoder, then if you have set the max feed rate to
500 IPM (the number you would enter is inches/second or 8.3333),
and you then command a feedrate of 250 IPM, EMC would output 5.0
Volts on the DAC. If there is a position error, that would add to or
subtract
from the 5.0 V.

Most encoder counters can handle 300,000 to 1 million encoder counts/second.
So, that would be 30 to 100 inches a second, or 1800 to 6000 IPM. Is that
enough for you?

The only downside to such huge numbers is the finite resolution of the DAC
voltage.

>2 for a multiple axis interpolation
>3 for a point to point traj
>
>

These make no difference, the code is the same regardless.

Jon