Auxmcu

##Safety watchdog##

The machine will need an interlock tied into the lid and e-stop, but some things are harder to detect via a simple switch, those are the things the watchdog routine monitors:

• Stepper clock to yank interlock if all steppers stop and the laser is firing (g-code crash)
• If the laser is on and we hit an end stop then the g-code has malfunctioned.
• Cooling water flow, stop if it's too low.
• Cooling water temperature, stop if too high.
• Exhaust air flow, stop if too low.
• Assist air pressure, stop if too low.
• Tube Voltage
• Tube Current

In addition the watchdog will also monitor the E-stop and the lid switches to be able to tell the user why we're stopping.

As an extra shutdown measure the watchdog will also control a mirror that can be moved into the beam to deflect the beam into a large metal plate, in case the PSU fails on, the same mirror will also engage the red aiming laser.

##Other supervisory duties##

The gcode interpreter will only control the motors and the laser, all other controls in the machine will be handled by the auxiliary MCU, such as:

• Reporting of all inputs to the controlling machine
• Exhaust relay
• Assist air relay
• Cooling fan (PWM 24 V)
• Cooling pump (PWM 24 V)
• Cutting chamber lights