GRBL AIO – Coolant Output

Connecting a Pump or other accessory to the GRBL-AIO Coolant Output.

Notes:

• The coolant output is for switching low voltage & low current DC circuits.
• You should be switching a relay if possible rather than powering your accessory via Coolant Pins 2 & 3.
• On occasions where your accessory requires less than a few amps then you may power it directly without a relay.
• You should connect the DC +ve to both pins 3 & 4 as shown in the circuit diagrams below.
• The Coolant control pin that is switched by the AIO is the GND which is on Pin 2.

Your Circuit.

• Your relay should have a constant connection to the +VE of the power supply.
• Its negative connection should be connected to Pin 2 on the Coolant Output port of the AIO.  It is this GND side of your relay’s coil that it’s going to be switched on by the AIO.

GCode Control of Output

• M7 – turn mist coolant on.  (Not used unless you have specifically reprogrammed the board)
• M8 – turn flood coolant on. (Shorts Pin 2 to GND)
• M9 – turn both M7 and M8 off. ( Pin 2 disconnected from the ground)