How to display the Inputs/Outputs in PlanetCNC & Test the sensors
▶ Description of the problem
You want to see the indicators lights for the limit sensors and the inputs (Z probe, enclosure...) to check if they are working properly, but PlanetCNC does not display this information by default.
▶ Solution
1. Follow the video and instructions to display the inputs/outputs:
- Go to: File > Settings > State > IO section > Click on "Show"
This will display a lot of different indactors so we will hide the ones that are not useful now:
- Scroll down and uncheck everything except LED Input and LED Limit
- Set the values of ExtIn and ExtOut to 0 to hide them too
- Click on OK
You now have a new panel on the left displaying the indicator lights for the different Limits and Inputs. A red dot will turn green when the corresponding sensor is activated.
2. Test all the sensors of the machine one by one:
Mechanical Limit Switch (Evo):
Press the button on the sensor
Inductive Limit Sensor (Pro/Fab):
Touch the sensor with a steel tool
Tool Measure Z-Probe:
Touch the probe with the crocodile clip
Enclosure Doors (optional):
Open a door to separate its connectors
If you made the connections correctly, the red dots should turn green when a sensor/input is activated, according to the map of your machine (see below).
If you notice discrepancies or if one of the indicators doesn't light up, please verify the connections on your control unit.
Evo
Machine's Sensor | PlanetCNC Indicator |
---|---|
X limit switch | Limit 1 |
Y1 limit switch | Limit 2 |
Z limit switch | Limit 3 |
Y2 limit switch | Limit 4 |
Tool Measure Z-Probe | Input 1 |
(Optional) Enclosure Front Door | Input 2 |
(Optional) Enclosure Back Door | Input 3 |


Pro
Machine's Sensor | PlanetCNC Indicator |
---|---|
X- & X+ limit sensors | Limit 1 |
Y1- & Y1+ limit sensors | Limit 2 |
Z limit sensor | Limit 3 |
Y2 limit sensor | Limit 4 |
Tool Measure Z-Probe | Input 1 |
(Optional) Enclosure Front Door | Input 2 |
(Optional) Enclosure Back Door | Input 3 |


Fab
Machine's Sensor | PlanetCNC Indicator |
---|---|
X- & X+ limit sensors | Limit 1 |
Y1- & Y1+ limit sensors | Limit 2 |
Z limit sensor | Limit 3 |
Y2 limit sensor | Limit 4 |
Tool Measure Z-Probe | Input 1 |


If this didn't help, please contact our support team for more information.