I am using ReplicatorG and occasionally get communications errors at which point the whole process goes into melt down and never recovers. On investigation I found the following:

The RepRep GCode spec (http://objects.reprap.org/wiki/GCodes) says that each line should start with 'ok' or 'rs' and ReplicatorG is programmed to do this. However the Gen6 firmware sends 'Resend' at the start of lines that need resending. Hence ReplicatorG never sends the line again and mayhem follows.

I have patched the following 2 lines in process_g_code line 738 - 738

char buffer[100]="rs ";
ltoa(gc.LastLineNrRecieved+1, buffer+3, 10);

This seems to have cured the problem. This would probably also affect any other driver s/w written to follow the information on the RepRap.org g code page.

Cheers
Geoff

It seems that libreprap (used by repsnapper) understands both "rs" (official) and "Resend".

fived.c:


Probably other apps support both too.