Is it possible to set the axis limits of axis 6 (KRC2) to more then 360°?
If so, what is the preferred procedure then?
Axis limit axis 6 KRC 2
-
Plc_User -
April 10, 2016 at 1:54 AM -
Thread is marked as Resolved.
-
-
rotary axis can be either endless (no soft limits) or must have soft limits that are within +/-358deg
-
If I change $SOFTN_END[6] in the $machine.dat file and load in by the console, I can raise it to 358, but higher values gives errors on loading.
I suppose 358 will be the real maximum for my robot? Or are there still other limitations that can be changed to make the range higher then 358? -
Hi,
you need to set your axis to endless using $AXIS_TYPE[6] = 5. If the axis is not endless (e.g. $AXIS_TYPE[6]=3) +-358° are the maximal values for any robot, because with the turn you can only separate two times 360° to be unique. Endless axes always run shortest path so no turn is used.
Fubini
-
HOWEVER!
If you set an axis to Endless mode, its motion behavior changes. It will stop moving absolutely in response to AXIS motion commands (like Home), and instead move to the nearest multiple of 360deg (or is it 180deg? Darn it, I can't remember offhand ).
That is, if you moved the axis to, say, 361deg, then ordered the axis to move to 180deg, it would instead rotate to 540deg (360+180). This is because, with a circular axis, the physical position of 180deg and 540deg is identical, and the distance from 361 to 540 (179) is slightly less than the distance from 361 to 180 (181).
What this means is that, if you have cabling running over the wrist to the tool, the rotation of A6 (or A4, which is the other axis you can set to Endless mode), the rotation can "build up" over time until you rip the cabling apart. So if you use Endless mode, you must take extra care to "unwind" the Endless axis in order to avoid this. Simply commanding PTP {A4 0,A6 0} could leave A4 and/or A6 at 0deg, 360deg, 720deg, etc.
-
What could be a solution then for having axis 6 to turn at f.i. +400° to -400° and always have the same absolute home position (fi 10° but not 370° or -350°) to make sure the cable isn't wound up?
-
-
Linear perhaps (careful there...)