Janos Dosa wrote: > We run into a problem on a 3 axis mill. > > We understand that the default mode for EMC2 is G64. (I think this is not a > very good practice, especially for mills.) > > Our problem is that we cannot switch from that mode. > We tried to put the G61 or G61.1 command into the lines. > > A video, that shows the problem can be downloaded from > > http://www.hex.hu/cncvideo/g61g64.mp4 > > It is about 1.5MB. It is recommended to download and magnify it in a > separate player. > > Please note the following: > Theoretically one axis should move at a time. > > The cursor that represents the mill bit works/moves correctly, although the > theoretical position is way ahead of the actual motion. Listen the sound of > the machine. > > Although one axis should move at a time, due to the constant speed mode 2 > axis is moving what is a big mistake for us. > At the speed of 2100 mm/min the error from the theoretical path is huge > around 50mm (2 inches) or so. Same problem in smaller scale if the machine > is slower. > > Changing the G64 mode to G61 or G61.1 or G64P0.01 mode does not change > anything. > > The version of the EMC2 is 2.2.4. > > The machine has digital servos capable to operate at 1MHz. (step/dir) > The machine if it operates at slow speed and there is a Pause command issued > at the endpoints, than works better in fact is very accurate at the end > points. > There is a feedback line from the glass scale(s) and there is a > reader/display unit that show independently the actual position from the > glass scale. > After a 96 hour continuous milling job the machine returns to 0.0000 with no > misalignment at all both the internal and external counter shows the same. > > Since the theoretical path and the actual movement significantly differs - > see the XYZ values and the cursor in the black square - and the G61,G61.1 > command does not change that it is possible that there is a bug in the > trajectory planner. > > Any idea how can we force the EMC2 to execute either the G61 or the G61.1 > command and switch the sw. to that mode?
Please use HalScope to capture the position commands coming out of the EMC motion controller during a right angle turn. It is difficult or impossible to troubleshoot motion control issues by watching the machine move. For example, very sluggish PID tuning could result in rounded corners. Only by examining the signals at intermediate points can you determine what is going on. Once you have the signals in HalScope, post a screenshot, either at imagebin.com or your own website, and post a link here. I'm away from my EMC computer, so I can't conveniently tell you the names of the HAL pins. I know they start with 'axis.(number).', and they probably end with 'pos-cmd' or something similar. Do a 'show pin' or 'show sig' in halcmd to find the proper names. Regards, John Kasunich ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
