You can have your Rapid Rate Override set to 25% in the PLC script on start up.
Put this code in the PLC Script from the screen editor.
--Featured added 11-9-18
--Set RRO to 25% on start up
if testcount == 1 then
mc.mcCntlSetRRO(inst, 25)
end
As far as playing a tone off the computer through speakers, I'm not sure, someone else would need to help you with that.
But, I have Stack Lights that have buzzers integrated in them on our machines here at the shop, you can use the "Tool Change" output in the mach configuration and map it to a relay that runs a buzzer or beeper. You can get simple buzzers on ebay or places like Automationdirect.com.