The R2 and C2 use an infrared sensor located behind the hotend (under the hotend fan) for sensing the distance to the bed for auto-leveling purposes. When the sensor is tripped, the bottom right corner of the PCB will illuminate red from a small LED light. It can be a little faint in a bright room, but it is easily visible from the right side of the extruder. If you are finding problems with you auto-leveling, it may be due to this IR sensor. The location of the IR sensor is shown in the picture below:
Step 1) Check the sensor manually.
1. Make sure your printer is on, and the nozzle is cool to the touch.
2. Take a piece of paper or your hand and place it about 5 inches away from the bottom of the tip of the nozzle and far enough behind the nozzle so that the IR sensor can see it.
3. Slowly raise the piece of paper up.
4. You should see the red light illuminate.
If you do not see any illumination, then the IR sensor is not plugged in correctly, or is damaged.
a. Checking the wire.
1. The flat ribbon cable leading into the top-most electronics on the extruder should be fully latched into place.
2. The IR electronics has a black 3 wire connector that should be fully plugged in (as shown in the image above, highlighted with orange boxes).
If the sensor is always illuminated: check for debris around the opening in the plastic at the bottom of the PCB, something may be reflecting the light back.
Step 2) Check with software (if Step 1 did not solve the issue)
Connect to your web dashboard by following the steps in this article.
- In the Printer Terminal pane on the main dashboard, type in the following command and press enter:
- M119
- If the sensor is not being tripped (red LED is off), the output should look like this:
- Recv: Reporting endstop status
- Recv: x_min: open
- Recv: y_max: open
- Recv: z_min: open
- Recv: z_max: open
- If the sensor is being tripped (red LED is on), the output will look like this:
- Recv: Reporting endstop status
- Recv: x_min: open
- Recv: y_max: open
- Recv: z_min: TRIGGERED
- Recv: z_max: open
If you are reading TRIGGERED when nothing is directly below the sensor, and the red LED is on with nothing obstructing the IR sensor, you may have a faulty IR sensor.
Comments
6 comments
An illustration of the location of the IR sensor and the LED would be useful.
@hamiltonl great point. Adding that into this post.
I can run through all the calibrations without error but when the R2 starts any print, the extruder buries itself directly into the print bed and errors out. I cleaned the IR sensor and the light comes on when paper is raised up just below it.
After sending the M119 command I get this:
Recv: Reporting endstop status
Recv: x_min: TRIGGERED
Recv: y_max: TRIGGERED
Recv: z_min: open
Recv: z_max: TRIGGERED
Any ideas? Bad IR sensor?
Hi ! I have the same problem, Did you solve it?
Hi Diana
The IR Sensor Board had failed. Robo shipped a replacement and all worked great after that. The only source that I am aware of is Partbuilt at https://www.partsbuilt.com/bed-sensor-r2c2-robo3d/ and they are currently out of stock. I would contact them to see what they suggest.
Sorry I am not more help.
The issue above sounds like a failed limit switch not a IR sensor.
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