I'm beginning to think that my english is not transparent enough....
@ Robin,
please allow me to re-summerise my query below.
As the PC station is away from the rig, what I am trying to achieve is to notify to the PC that eStop has been pressed that any further data received (ie until the loop restarts if a Goto 0 is really not possible) is invalid
The eStop button kills the power to my rig as should any eStop button.
the arduino board is connected, powered and communicating with a PC and therefore will not power down when the eStop is pressed (unless I do what UKHeliBob suggested which is not really my preferred option)
I would like to implement an INTERRUPT to detect the eStop condition, so that the arduino knows that an eStop has happened and that, where ever it is in "loop", whatever data it is receiving is now invalid
To avoid me adding many "if" statements checking the eStop variable in my loop surely there much be a way of implementing a "Goto 0" which the start of the loop so that I have only ONE if statement that checks the eStop to decide whether or not to run the "normal" code
so is psudo code:
on interrupt{
eStop= 1;
}
void loop{
if(eStop!=1){
//normal code
}
else{
//eStop codition
}
}