Move would exceed limit appears, for no reason

Hi There,
so I have a machine with 350x500x107(XxYxZ), it runs with steppers over the parallel port.
A few months ago I decided to add a extruder to the machine to be able to print some 3d stuff and also built a heated bed.

For some time the machine looses steps or sometimes worse things happen (y axis is driven by two independent steppers) and I tried to find some safe parameters. For now the movement seems to work but now another issue showed up:

The machine sometimes stops with an "Linear move would exceed joint 3' positive limit", and as far as I can tell, this means I try to drive outside of my defined limits, but jumping to that line doesn't show anything suspicious.
After the error apeared I can't start my application from any line ("Run From here" in axis gives me that error with any line I try to run from).
Restarting Linuxcnc, rehoming and running from that exact line afterwards works.

Only thing I have to add, it's a 3d file, so the Gcode has 17MB (or even more).

Does anyone has an idea what is happening or maybe someone can relate such a behaviour to any known issue?

Thanks in advance
Anton

Just realised the error specifies 'joint 3'

So this relates presumably to whatever unspecified stuff you did to add an extruder.

It could be the error is simply because you have not touched off that axis.
Hard to say much more without any info.

eg. What is on that line of gcode, what is joint 3? etc

regards

the relationship between joints and axis is 012345 xyzabc
so joint 3 is a which presumably is your extruder

try setting in your ini under joint 3
MIN_LIMIT = -1000000.0
MAX_LIMIT = 1000000.0

axis knows nothing about your a axis being an extruder i,.e no limits as to how far it can travel , and as it thinks it's a linear rail for example it has only a exact distance it can travel
so you just need to be able to travel further than the axis can move , you can get a hint in your sli3r gcode as it says how far long the extrusion is i.e 4m 3,6000 etc , so make sure in the ini file
the extrusion can travel that distance before hitting limits ,.

i'm sure theirs a setting for essentially turning off limits for an axis , but i cant' find it at the moment

you also say your missing steps , this is usually because your moving the axis faster than it's capable , so try slowing it down
or increasing the stepper driver voltage and current can help , but of course keeping just under the max voltage .

remember the faster a stepper moves the less torque it has , increasing the voltage and current will help here
hence the lost steps

Hey you guys,
sorry for the late reply, but just had a busy week.

Anyhow, it realy was the limit on the A axis, since stepconf does set it to 9999 to -9999. That is fine for a lathe (at least I think so) but inssuficient for an extruder.
I must confess, I'm a little ashamed I didn't figure it out by myself, but now I am happy printing the whole day.

So again, thanks for the hints.

Anton