Hi Eon,

For executing an "Action" on startup see the help (Prog Startup):

Regarding having one Thread or loop doing multiple things: there are various approaches depending on how involved the things you are trying to do simultaneously.  If all you need to do is something relatively instantaneous (ie disable something when an input changes)  it is relatively easy.    In this case just make one loop that checks multiple things.  See the ExternalButtons.c example.  It uses a helper function (Debounce) and a few variables to keep track of if the input changed and for how long and returns a code to tell you when the input changed without ever waiting for anything (which would block other activities in the loop).

The example ServiceToolChange.c is an example of how to perform a multistep process without ever blocking.  This program is written in the form of a "State Machine".  This is a bit more complicated than a simple sequential program that executes in a linear fashion.  The advantage of this approach is that it doesn't need its own Thread to execute a sequence that might take a while.  Also this approach works if you want to have external tool change buttons to invoke the sequence (not necessarily form GCode or KMotionCNC).  The advantage of a "state machine" approach is that it always keeps track of its state (exactly what it was doing) in a state variable and other variables.  This allows the processor to go away and do other things at the same time (watchdog, pendent, switch inputs, spindle, etc...) and then come back, realize what they were doing, and resume what they were doing for a bit before again going away.  Most programs like a tool changer program will spend 99.99% of its time simply waiting for something to happen.  These are usually: #1 waiting for a motion to complete, #2 waiting for an input to change, or #3 waiting for a delay to pass.   So the idea is basically to remember what state we were in.  For example waiting for a delay time to go by.  Let's say we want to bake a cake for an hour. A sequential program would: turn on the oven, delay(sleep) for an hour doing nothing, then turn off the oven.  A state driven program would turn on the oven, then look at the clock, add 1 hr, and write down that as the final time (ToolTime).  Now he is free to go away, run other errands, as long as he comes back every minute or two and checks the clock (Time_sec()) to see if it is past the final time.  If not just exit and do nothing.  But if it is past time, then turn off the oven and switch states to something else.

HTH

Regards

TK