NOTE: only LEDs set up for ‘inputs’ like limit switches and E-stop buttons need the hardware to be hooked up to confirm an incoming signal. Otherwise, LEDs for ‘outputs’ like PWM or motor signals will still turn on and off without needing to hook up the components.
| Section | # | Why is it lit up? | Type | Colour |
| Power | 1 | E-stop pressed or power disruption | In | Red |
| 2 | 5V power is working on the board | In | Green | |
| 3 | 3.3V power is working on the board | In | Green | |
| Communication | 4 | RS485 TX signals are being sent | Out | Green |
| 5 | RS485 RX signals are being sent | In | Red | |
| 6 | USB connection is active | Com | Green | |
| 7 | CAN bus TX signals are being sent | Out | Green | |
| 8 | CAN bus RX signals are being sent | In | Red | |
| 9 | Ethernet is connected at the standard speed *Side of board where plug goes in | Out | Green | |
| 10 | Ethernet data is being sent/received (blinking) *Side of board where plug goes in | Com | Yellow | |
| Accessory Outputs | 11 | Switch 1 output is active | Out | Green |
| 12 | Switch 2 output is active | Out | Green | |
| 13 | Aux power 1 output is active | Out | Green | |
| 14 | Aux power 2 output is active | Out | Green | |
| Spindle/RS485 | 15 | Laser PWM output pin is sending signals Note: this is not dependant on $32 or gSender being in laser mode, this relies on the active ‘spindle’ output being “SLB_LASER” and there being a specified power output while M3 or M4 are on, see the laser section to read about this | Out | Red |
| 16 | Spindle PWM output pin is sending signals Note: checks and setup for this is the same as for the laser PWM output above, also only one of these lights will be able to be on at one time since only one ‘spindle’ can be active at once | Out | White | |
| Limit Switches | 17 | Z-axis limit switch is closed | In | Yellow |
| 18 | Y2-axis limit switch is closed | In | Yellow | |
| 19 | Y1-axis limit switch is closed | In | Yellow | |
| 20 | X-axis limit switch is closed | In | Yellow | |
| Rotary | 21 | A-axis limit switch is closed | In | Yellow |
| 22 | A-axis motor is reaching its stall point | Out | Red | |
| 23 | A-axis motor is enabled Note: depending on what external motor driver you wire up, this light might be inverted and instead light up for ‘disabled’ | Out | Green | |
| XYZA Axis Enabled | 24 | Z-axis motor is enabled | Out | Green |
| 25 | Y2-axis motor is enabled | Out | Green | |
| 26 | Y1-axis motor is enabled | Out | Green | |
| 27 | X-axis motor is enabled Note: all motors will typically light as ‘enabled’ for any movement, unless they’re constantly lit from keeping them energized using $37 | Out | Green | |
| XYZA Axis Stalled | 28 | Z-axis motor is reaching its stall point | Out | Red |
| 29 | Y2-axis motor is reaching its stall point | Out | Red | |
| 30 | Y1-axis motor is reaching its stall point | Out | Red | |
| 31 | X-axis motor is reaching its stall point | Out | Red | |
| Main LED Strip | 32 | Flood command (M8) is on | Out | Blue |
| 33 | Mist command (M7) is on | Out | Blue | |
| 34 | Door input signal is closed | In | Yellow | |
| 35 | Tool length sensor signal is closed | In | Yellow | |
| 36 | Probe input signal is closed | In | Yellow | |
| 37 | Action button 1 is being pressed | In | Yellow | |
| 38 | Action button 2 is being pressed | In | Yellow | |
| 39 | Action button 3 is being pressed | In | Yellow | |
| 40 | E-stop is pressed (circuit open) | In | Red |