JV,
Only install the Red warning lamp and use the other NO to signal MASSO. Set the temp trigger point the same for both circuits. The Red lamp is connected to the O/C NO contact and MASSO input is connected to the closed NO contact. That way when the trigger temp is reached Red lamp comes on and MASSO shuts down.
Now the best input to use is the coolant flow input as that stops movement and turns off VFD.
I installed a flow switch in the coolant return line, so if for some reason coolant stopped coming back to the reservoir, MASSO shuts down. I haven't had a job yet, that ran long enough to overheat the spindle or even for that matter to get warm enough to worry about.
Regards,
Arie.