Problem 1: Near Line XX Linear Move Exceeds Joint X’s Positive/Negative Limit

Explanation:

This error means that the toolpath/G code is telling the machine to go past one its travel limits:

Joint 0 = X axis

Joint 1 = Y axis

Joint 2 = Z axis

Joint 3 = A axis

Joint 4 = B axis

Possible Solutions:

  1. If the error is on joint 2 (Z axis), check if your tool length offset is set correctly. See the “Tool Length Offset” tutorial for more information.

  2. If the error is for exceeding the negative limit of joint 2 and the tool length offset is correct, increase the tool stickout or switch to a longer tool holder.

  3. If the error is for exceeding the positive limit of joint 2 and the tool length offset is correct, decrease the tool stickout or switch to a shorter tool holder.

  4. Check if your toolpath is asking the machine to exceed its limits of travel. Open your code in a text editing program and use the search bar (CTRL + F) to search for any values that are greater than the limits of travel for the Pocket NC mill.

The X limits are -2.00 to 2.55 inches

The Y limits are -2.4 to 2.6 inches

The Z limits are -3.45 to 0.10  inches*

The A limits are -25 to 135 degrees

The B limits are -9999 to 9999 degrees

5. Adjust the location of the part/stock so that it is within the Pocket NC’s work envelope

6. Decrease the retract height on the toolpaths if the part is close to the limits of the Pocket NC’s travel.

7. Oversized parts may be able to be fixtured and cut one side at a time instead of all in one program. 

Problem 2: 14 Unexpected Real Time Delay on RT Thread 1

Explanation: This error means that there has been a delay in the Beaglebones processor.

Possible Solutions:

  1. This error can be caused by a temporarily dropped connection between the computer and the Pocket NC mill or by a program that is so large and complicated that the Beaglebone’s processor cannot keep up. 

  2. Check that the connection between the computer and the machine is good.

  3. Try slowing down the feed rate or reducing the file size of the G code file by breaking it into more than 1 operation or by loosening the tolerances in the toolpath and reposting it.

Problem 3: “Cannot unhome while moving _ Axis” or “Homing Sequence Already in Progress”

Explanation: This error means that a homing process is currently underway, but a second homing process has been commanded.

Possible Solutions:

  1. Use the Home All command by itself and wait for completion before issuing another homing command.

  2. Home individual axes one at a time and wait for completion before starting a second homing sequence.

Problem 4: “Joint 4 Following Error”

Explanation: This error occurs when the corresponding axis (B axis in this instance) will not complete the commanded move in the predicted time. The Penta Machine simulator will not detect this error since it is not limited by the physical constraints of the machine.

Possible Solutions:

  1. Missing Calibration:

This error will occur when the machine’s calibration file has not been uploaded to the machine. If your machine’s B compensation table is blank, your will receive a “Joint 4 Following Error” whenever the B axis is commanded to perform a rapid move (example: G0 B270).

2. Feed Rate Too High:

G-code commands G93 (inverse time mode) and G94 (units per minute mode) can cause a “Joint 4 Following Error” if the F value is too high. Reducing the Feed Rate slider on the machine’s user interface usually resolves this problem.

3. Acceleration Change Too Great:

A “Joint 4 Following Error” can occur whenever the commanded axis (B axis for the Joint 4 Following Error) reverses direction at high feed rates.

Notice in the code shown above that the B axis reverses direction on line N39880. The above g-code example uses the G93 command (inverse time mode).  A feed rate of F1200 means that the B axis needs to move roughly one degree every (1/1200)*60 seconds or 0.05 seconds.  This 20°/sec (1°/0.05sec) is within the machines velocity specification, but the change in velocity (you basically double this number because its changing direction) is exceeding the machine's acceleration limit.

Again, reducing the Feed Rate slider on the machine’s user interface usually resolve the problem.