I`m also keen to find a solution to this problem.
I have tried using M8/M9 to control my water spray solenoid valve,
also tried M3/M5 with PWM and got slightly better results playing with the spindle
pulley speeds and PWMBase Freq. I can still visually see the overshoot of flow after
turning the solenoid off.
Realistically there is obviously a certain amount of water exiting the valve
at the Off command until the solenoid is physically closed.
The Valve driver info states there is approximately 0.3 ms response time of the valve,
so I`m not sure if it`s just an accumulation of time from the
Off command - thru Mach3 - thru the port - thru the breakout - thru the driver - to the solenoid.
And yeah, bear in mind my table speeds are around 12-15 Meters/min (around 500 IPM)
(not asking a lot, expecting it to stop flowing over a distance the size of a pin prick

What I`d like to do is be able to verify the signal times running in unison with
my axis stepper motors.
Is it possible to get some software to measure the wave forms without an Oscilloscope ?
So far all my searching suggests you need to output the signals thru the parallel port
before you can read them back into the pc.
I am a bit loathe to cough up for an oscilloscope. Any suggestions would be much appreciated.
arturoc - just as a matter of interest, what sort of diameter is your laser beam and how high
is it set off the work plane ? Would it be possible to have a mirror mechanism to deflect the beam
and prohibit the cutting action at the execution of an M5.
Perhaps this would be faster than turning the laser off. Please ignor my ignorance of laser machines.
you can read some of my machine exploits here
http://www.machsupport.com/forum/index.php/topic,4926.msg34384.html#msg34384