CNC Troubleshooting | Router | Axis Limiter Sensor


If you see this error it is because the ShopBot CNC hit a limiter sensor or proxy switch that caused a fault in the calibration and requires re-calibration.


The Shopbot CNC machines are designed with a limit sensor for each axis. One of the limiters is a physical stop to keep the gantry from walking off the rails; if you hit these you will have to re-initialize the Shopbot CNC machine. The other limiter is a light sensor to assist the machine with it's 'homing' function (C3). It is important to not enter commands that are beyond the limits of these machines. For example; both of our CNC machines have a 60" Y axis and a 96" X axis beds. pushing either of these numbers beyond their limit will incur a limiter switch error.

  1. Turn off CNC Control box
  2. Close ShopBot3
  3. Fix axis proxy switch (lowering spindle 1")
  4. At least 30 seconds should have passed since turning off the CNC Control box so that it forgets its settings
  5. Start CNC Control Box
  6. Press Blue Reset button
  7. Launch ShopBot3
  8. Enter command Z3 to zero all 3 axis (X, Y, Z)
  9. Enter command C3 to calibrate machine
  10. Proceed back to 'Part 1: Machine Calibration'