Backplot trail changing colour during millimg

I'll think that in milling operation from start to finish the backplot colour should change gradually from white to red.
So in the end of the process backplot trail or trajectory is totally red. I have found that in during milling suddenly the history of the trail
is chainging back white again. In the end some part of the trail is red and former is white. There is no relevant information left concerning
colour information of milling. Is this some program memory problem?

Iselman

If I correctly understand your issue then, yes Axis only keeps a rolling history of the moves in the back plot screen. After that is reached moves start to roll off the history and revert back to white. I don't think it's a memory limitation as much as a program designed limit.

In older versions of linuxcnc this colouring worked fine, from job start to finish. In start, trail is white and in the end totally
red. Now during job the colour change back white with certain time in older trail history. This is happening continously.
So, in the end latest trails are red and older ones white. I don't care this so much, but when milling PCBs(printed circuit boards), one can see this mechanical ecthing (copper milled on fiberclass board), that this is happened on the whole board.

In what older versions? The behavior has been the same as long Ive used Linuxcnc (since EMC2 version 2.4).

I have the same issue and I am on 2.8.

I am contributing it to high CPU usage and memory in my case.

The number of points retained by the position logger is a compile-time constant.
you can change it if you want to build from source but there may be consequences
depending upon the speed or memory limits of your machine.

github.com/LinuxCNC/linuxcnc/blob/51a886...s/emcmodule.cc#L1741

#define MAX_POINTS (10000)

The last time it was changed was in 2009:
github.com/LinuxCNC/linuxcnc/commit/13e7...418cfbc117436d8c9f38

As far as i can tell, the 10000 value has been same since at least the v2.4_branch

Now I got it, it is really realtime computer resource problem concerning processor speed, amount of memory and operating system capability.
My controller computers are older PCs inside the cabinet, under the rebuild Isel 3-axis desktop mill..

Thanks for your attention!

Iselman

Here is a picture of my cnc system.