Help! Something has gone terribly wrong! Bug?

Hello. I seem to be experiencing a bug with EMC2, which is visible through the AXIS interface (and perhaps caused by AXIS? I'm not sure exactly what AXIS does).

The problem is that when I run a particular program, at a particular point in the program, all three axis suddenly begin to rapidly move several inches when they shouldn't.

The following screenshot shows the problem (I paused the program soon after it started moving incorrectly) -- note that at the bottom of the screen it shows the command in the program that it is currently executing (G01 X3.5688 Y0.1734 Z-0.592 F10). Note also that the current X Y and Z positions are all within half an inch of this position. Then notice that the distance-to-go-X (DTGX) is 3.6 inches, and there are similar problems with the other axis. The A axis seems to be on its way to 90 degrees, with no reason for doing so that I can think of.

I have experienced this once before with a different, simpler program. If I remember correctly, it would not happen at the same point in the program every time, but rather at random points. It is as though it suddenly switches coordinates (e.g., G54 to G55). If you know what is happening, please help! Thanks! I'm running EMC 2.3.5 with AXIS 2.3.5.

you are running version 2.3.5 ... are you able to upgrade to 2.3.5
or post gcode program which shows fault

I have attached the gcode. It is generated by a program I wrote, and is quite long (almost 20,000 lines). It also contains some subroutines (O100 and O200). Is there any chance the length or the subroutines could be causing a problem?

I could upgrade to a different version but I am hesitant to do so unless I know that doing so would fix this problem. This is not a known bug?

Thanks for any help!

The problem is that when I run a particular program, at a particular point in the program, all three axis suddenly begin to rapidly move several inches when they shouldn't.

I have experienced this once before with a different, simpler program. If I remember correctly, it would not happen at the same point in the program every time, but rather at random points. I

Have you determined if the problem is always at the same point now?

If so could you show what portion of the code is the problem?

I believe there may have been bug fixes for subroutines since the version you are running.

Rick G

Have you determined if the problem is always at the same point now?

I have only run it twice, but it happened at the same spot each time.

If so could you show what portion of the code is the problem?

As previously mentioned and shown in the screenshot, it happens on or near the line "G01 X3.5688 Y0.1734 Z-0.592 F10" which is within subroutine O100

I would say that your g code is causing the problem as there is no known bug in EMC that will cause it to go where it is not commanded to go.

I would say that my g code is definitely not causing the problem, since there is nowhere in the code that has the X axis go anywhere close to +7", which is where it was going.

The length of the file is not a problem as long as you have enough memory to load it iirc.

What if I do not have enough memory to load it? Will it give me an error message, or will it try to run it anyway, resulting in strange things happening?

Some things to look for are subroutines that don't have unique numbers, subroutines before the call which would use subroutines in your directory instead of the one in your file.

This is backwards. Subroutines may only be called after they are defined. (see linuxcnc.org/docs/html/gcode_main.html#r3_1 ). The names are unique, and it begins running the subroutine correctly. Then, in the middle of the subroutine, it goes crazy!

Thanks for the responses. Please help!

I have eliminated memory as a possible cause. I checked, and I was using about 300MB of memory and I only had 256MB of physical memory, so this seemed like a likely problem, but I replaced the memory with a 1GB memory card and I am still experiencing the problem.

My most recent test (new but similar program) has yielded very strange, similar but distinctly different, results:

After running for a while, the program suddenly jumped back to a previous part of the program, and started running from there. I let it keep going, and at the same point it suddenly jumped back again to a slightly different point.

Here is what the program looks like:

O100 sub
stuff
O100 endsub

O200 sub
stuff
O200 endsub

O100 call
stuff
*!*!*!*!*!*!*!*!*!
stuff
O200 call
stuff

At the point where I put in *!*!*!*!*!*!*!*!*!, it suddenly jumps to a point right in the *middle* of the O100 subroutine. This has happened repeatedly for different large programs of mine. It sometimes jumps from the same point repeatedly, and sometimes jumps from random points. It only happens with large programs, and it seems like a bad pointer somewhere. Someone out there MUST have experienced this. It is definitely NOT a problem with my g code.

It seems possible (although this is just a guess) that it is jumping to the point where the coordinate system was last changed (e.g., G55 to G56).

UPDATE: I replaced each subroutine call (e.g., "O100 call") with the contents of the subroutine, thereby eliminating the subroutines altogether. This fixed the problem. There is definitely a bug in EMC2 related to subroutines!

NOTE: I was a bad scientist, and I manipulated two variables. The other thing I changed is that I removed the line numbers. It seems very unlikely that this would do anything, but ya never know.