Re: Motion Controller board ?

Dave,

The PMDX-121 breakout board supports the "charge pump"
as implemented in Mach2 and Mach3.

This is a signal that pulses rapidly while the Mach
program is running. It is fed into a "charge pump"
or watchdog circuit that looks for the rapid pulses
and enables the outputs on the breakout board. If
the rapid pulses are not present, the outputs are
inhibited. This is used to prevent accidental machine
motion, spindle enable, coolant turn on etc. during
the time the PC is booting or if the Mach program
should crash.

The use of the "charge pump" signal is optional on
the PMDX-121 and is a configuration option in Mach.

To my knowledge no other CNC control program being
offered to hobbyists supports this function.

The "charge pump" interlock feature is also available
on breakout boards from Sound Logic and possibly
others but to the best of my knowledge the PMDX-121
is the least expensive solution for a small machine
that has a relay usable for spindle control and with
the "charge pump" safety interlock.

Regards,
Steve Stallings
www.pmdx.com



--- In CAD_CAM_EDM_DRO@yahoogroups.com, "turbulatordude"
<dave_mucha@y...> wrote:
<snip>

> What is the benifit of the charge pump on the breakout board ?
>
> Also, there was some talk recently about the Mach2 interface and

the

> breakout boards.
>
> Do you offer a board that looks for the Mach2 signal and holds off
> outputs until there is a proven value on that line ?
>
> Dave