Problem
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.

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