wj200-vfd segfaulting after updates

Okay, after some effort and a bunch of printf statements (I went old school on debugging) I found the problem.

In line 94 of wj200_vfd.comp, the definition:

bits[10]

should be changed to

bits[16]


... because 10 isn't large enough for the data returned from libmodbus, and the overflow was clobbering the pointer to the __comp_inst structure inside the loop FOR_ALL_INSTANCES().

I am guessing libmodbus changed something in the most recent version or else the author of the code was lucky enough to never hit the bug (like I was with the previous incarnation of my linuxcnc system).

I doubt that wj200_vfd has completely worked since prior to version 2.6, although I'd guess that there are some people using it and it works just fine for them. /shrug.

Can someone please email this to the emc-developers list so the fix gets into the main code stream?

Thanks,
Erik