One reason I hate to leave a small job running is because I hate to leave the spindle going after the job is done. I've been thinking I need to add a relay to turn on and off my spindle (and coolant later) at the beginning and end of a job at the very least.
The Altronix RDC48 looks like the ideal relay for the job. Its 48VDC operation so I should be able to run it off the same power supply everything else runs off of. Maybe throw a diode or an MOV across whatever switch I use to trigger it to protect the switch. The coil only draws 20 mills so that's probably just paranoid overkill, but still... Since its only 20 mills i really don't need to worry about the load on the power supply.
Its rated for 10 amps on the contacts so it should be able to handle my palm router spindle just fine, or my lighter duty rotary shaft motors. My only concern would be arc carboning the contacts. Since the router is soft start that might not be such a big deal.
So... on a G540 what pins/terminals are available for triggering it, and how would I configure Mach to do the job automatically at the beginning and end of every code file?
Since its DPDT I could use it to switch both my coolant pump and my spindle. Maybe add a seperate switch to the coolant pump for when I want to dry cut.