Comm Buffer Issue?

[AndyB]

Hi Guys,

I've been running a machine with v1.2008 for years and years and after some initial teething problems, it's been super stable. It's been probably 5 years now.
I recently put another machine into service with 1.2049 recently and today had the following gouging issues. I made 10 other necks today that didn't have any issues. Checked the code and it is not an error in the G-code.

I kinda sorta vaguely remember that I might have had this same exact problem when I was getting started with UCCNC and the solution was to increase the comm buffer size. I guess with an empty buffer the UC100 still moves axes or something until it gets fed again. I upped it to 200mS after the first gouge and then got the second gouge. I've upped it to 300mS but haven't tried yet.

Has anyone else seen this? I'm waiting to get comfy with 1.2049 before I switch the old version over to the new and want to make sure this is something simple like comm buffer size and not something like the dreaded Mach 3 bugs of old.

p.s. I measured the long gouge at 1.45" so at 570ipm that would take about 150mS. I'm thinking I might need to go up to 400mS?

Thanks in advance.

[cncdrive]

If the buffer runs empty then the controller has to stop the motion, it happens with decceleration otherwise the motors would loose steps with an instant stop.
Normally this should not happen, if the communication latency between the computer and the controller is OK. Then the buffer should never run empty.
Not sure that this happens, this is just an idea about the issue.
On our computers which we using for tests the software runs fine with as low as 50msec buffer size, but ofcourse the minimum OK buffer size depends on the computer...

[AndyB]

These are old computers so that's why I'm thinking possibly comm buffer issues. I checked the older machine this morning and I had the buffer size set to 400ms already. That combined with my vague memory of this happening before makes me think that this is indeed a com buffer issue.

Hardware is UC100 by the way.

I'm running another 12 necks today so we'll see how it goes with the increased buffer size.

[cncdrive]

Andy,

Why don't you upgrade to a new computer?
I guess that a guitar neck like that is more expensive than a suitable new computer.
Nowaday computers mostly all do the job. (Ofcourse I'm talking about PCs and not thin client computers and tablets.)