Is there a precision command for movements?

More
30 Mar 2011 17:12 - 30 Mar 2011 17:43 #8288 by dibella
I am running EMC2 on a laser machine. Previously, with the 30 year old Bosch Controller, it worked perfectly. It went exactly where the program code said.
Now, it rounds up. The faster it works, the more it rounds up. And it even shows on the monitor that it doesn't follow the program code.
Is there a way to force the software to avoid this?
It is absolutely not a machine problem. In the past, we ran the machine at 5 times the usual speed, and it moved exactly it should. Not it doesn't do it even at the normal speed.

I also checked: My NC Code header contains G61. I don't know if that is enough, and if I also need G61.1 and where.

Thanks in advance!
Last edit: 30 Mar 2011 17:43 by dibella.

Please Log in or Create an account to join the conversation.

More
30 Mar 2011 17:25 #8290 by BigJohnT
A must read chapter for "new to EMC" folks...

www.linuxcnc.org/docview/html/common_User_Concepts.html

John

Please Log in or Create an account to join the conversation.

More
30 Mar 2011 18:57 #8291 by cncbasher
i would suggest you check you motor drivers ( again i presume it is using servo drives , but please correct if i am wrong ) and configuration of analog input drives and signal voltages , this type of problem suggests some miss tuning or follow error etc
you say it ' rounds up' can you give some specifics etc

even changing from your old controller to emc would require your origional drive input to be adjusted to match emc2

can you give some information on pc setup and how you interfaced to emc2
so the problem can be narrowed down for you

Please Log in or Create an account to join the conversation.

More
30 Mar 2011 19:12 - 30 Mar 2011 19:13 #8292 by BigJohnT
The problem is usually that a new user has not read the few pages I linked to regarding Programming the Planner and do not understand what the result of using G64 vs other trajectory control commands.

I see the edit now that he is using G61 so that indicates a mechanical/tuning issue.

John
Last edit: 30 Mar 2011 19:13 by BigJohnT.

Please Log in or Create an account to join the conversation.

More
30 Mar 2011 19:21 #8293 by dibella
I had a Bosch Micro 8 controller on the laser machine. The servo drives are also Bosch.
I suspect that the Micro 8 had a specific parameter configuration on how to handle lines and arcs of different sizes.
I'll try to get information from the manufacturer, since the guys who installed EMC2 (with interface boards they developed) also are new to this situation.

If I still need help I will appear again.
Thanks a lot!

Please Log in or Create an account to join the conversation.

More
30 Mar 2011 19:29 #8294 by BigJohnT
If you program G61 that is exact path mode which means it will follow the exact path no matter how slow it has to go to do so. The screen is not updated in real time so you can't go by the backplot especially if it is zoomed in a lot.

John

Please Log in or Create an account to join the conversation.

More
30 Mar 2011 19:39 #8295 by dibella
Dumb question:
I have G61 twice in my NC Code. Does the second one turn off the command? Because it really doesn't follow the programmed path and instead to make a corner of 90 degrees, it makes an arc at the end of one line, before it makes the following straight line.
Maybe I should delete one G91 and try what happens.

Please Log in or Create an account to join the conversation.

More
30 Mar 2011 19:54 #8296 by BigJohnT
A second G61 will not turn off the first G61. If your machine does not follow the exact path (can't look at the screen because it is not updated in real time ) something is wrong with your machine and you might have a huge following error or some other cause.

John

Please Log in or Create an account to join the conversation.

More
30 Mar 2011 19:55 #8297 by BigJohnT
Are these G0 moves that make an arc?

John

Please Log in or Create an account to join the conversation.

More
30 Mar 2011 20:11 #8298 by dibella
No.
G0 is used for fast moving. G1 for moving while a tool is on and for lines. G2 for arcs with tool on.
If I have a small square, it doesn't cut perfectly at 90 degrees. The difference is visible. At the end of a line, it doesn't go straight to the beginning of the next line, at the point that should be the corner. It makes a small arc. The real corner is outside of the figure it cuts and isn't touched by any line.
I see this one the screen too, but I do not understand, why it happens, if I have G61 at the beginning of the code.
Could it be that due to modifications made to EMC2 to work with our machine, it forgets about G61?
As I understand, G61 is mandatory and should create weird behavior in form of sudden stops.

Please Log in or Create an account to join the conversation.

Time to create page: 0.138 seconds
Powered by Kunena Forum