Closed processing for an endlessly rotating slave axis

In the case of interpolation between the interpolation points, there is a need to distinguish whether the slave is to process the cam as endlessly rotating or with finite rotation. This information is also not included in the case of the current cam description. As the same cam description may be used for both types, this distinction is not a characteristic of the cam but is rather a component of the (CamIn) command.

In the case of endlessly rotating processing, the table interpolation points that are used to calculate the interpolation must be corrected by one modulo range at the cam's definition limits. The correction direction depends on whether the cam has been modelled for a forwards or backwards rotating slave.

However, the ISG slope kernel for cam processing (sl_cam_kernel) can only automatically do this correctly if no intermediate interpolation is used between the table's interpolation points (MC_CamIn.TableFktType = HLI_STEP_DIRECT) by ensuring that, for two successive, scanned slave positions, the shortest modulo distance is always output as the relative distance per real-time cycle. The modulo range of the slave axis is used for this calculation and this is why cam processing exclusively with modulo rotating slave axes is also possible.

If the cam has been modelled for an endlessly rotating slave axis, in connection with the use of interpolation point interpolation (MC_CamIn.TableFktType = HLI_LINEAR or HLI_POLYNOM_3), it is necessary to specify in which direction modulo correction is to take place.

If the cam has been modelled so that it passed through the slave's modulo range in the positive direction, in "MC_CamIn.StartMode" the bit:

HLI_CI_ENDLESS_POSITIVE     : DWORD := 16#0x00000020;

must be ored.

If the cam passes through the slave's modulo range in the negative direction, in "MC_CamIn.startmode" the bit:

HLI_CI_ENDLESS_NEGATIVE     : DWORD:= 16#0x00000040;

must be ored.

Nevertheless, the cam profile must always match the chosen processing mode as otherwise this results in abrupt changes in the slave position.