My blast gates on my system are controled with a pneumatic cylinder. I would like to automate opening and closing the blast gate with the system.

I need to send a short pulse to open the blast gate and a short pulse to close it. If I control these with M7 or M8 for on, and M9 for off. A continuous pulse is sent to the relays opening/closing the cylinder.

How do I set the system so that a short pulse is sent with M8 or M9?

Or can I do something different and some how send a command when the spindle is turned on?

I'm just not sure what the correct way to do this is.

Winging it here.  Just an approach.
Create a register: GateState, set it to 0
Add to your M3 macro
local mInst = 0;
if (mcRegGetHandle(mInst, "core/global/GateState", &hReg) == MERROR_NOERROR) {
   rc = mcRegSetValue(hReg, 1);
}
Add to your M5 macro
local mInst = 0;
if (mcRegGetHandle(mInst, "core/global/GateState", &hReg) == MERROR_NOERROR) {
   rc = mcRegSetValue(hReg, 0);
}
in the start script declare a variable LastGateState and set it to 0
In the signal library Check to see if the state has changed
mInst = 0;
if (mcRegGetHandle(mInst, "core/global/GateState", &hReg) == MERROR_NOERROR) {
   local gatestate = mcRegGetValue(hReg, 0);
}
if LastGateState~=gatestate then{
  send your pulse
  lastGateState=gatestate
}

Syntax is probable wrong but you get the idea.  Someone else may have a better method.

HTH

RT

This is great thanks. I get the idea.

After thinking about for awhile I decided I am going to use a couple of unused M commands. I mill aluminum semi regulary, and don't want the DC on then. If I create custom M codes that would be better for my situation, although I will have to manually insert them in the output that fusion creates for me, But no big deal.

Just create your m7 or m8 macro and within this just turn your signal on then back off, if its too quick then just add a wxSleep after the signal on.

DazTheGas