Referencing modes

The NC system supports different referencing modes, depending on the encoder system type.

• Homing based on reference cam (Plc Cam)
  The simplest axis referencing mode uses a reference cam that generates a digital signal at a defined position along the travel path. During homing the NC determines the signal edge and allocates a configurable reference position to this position. Referencing based on a reference cam is always possible, irrespective of the encoder type, and is a prerequisite for other, more precise modes.
• Software Sync
  Software Sync mode enhances the homing precision by additionally detecting the encoder count overflow after an encoder or motor revolution, after the reference cam signal has been detected. This mode requires a part-absolute encoder (e.g. resolver) with constant overflow interval relative to the reference cam. Overflow detection is parameterized via the Reference Mask parameter (see System Manager section).
• Hardware Sync
  Some encoder systems provide a sync pulse per revolution (zero track) in addition to the count. The homing precision can be enhanced by selecting this mode, if the encoder evaluation logic is able to pick up the sync pulse. The precision is comparable with Software Sync. Hardware Sync mode may require parameterization or special wiring of the drive or encoder system.
• Hardware Latch
  Hardware Latch reference mode (Hardware Latch Pos or Hardware Latch Neg, depending on edge) requires an external digital latch signal for storing the encoder position in the evaluation unit of the encoder system. The encoder system must support such a latch function and may have to be configured first in order to be able to utilize this function.