Some tasks, such as reading from and writing to the encoder memory, have low timing demands. For these kinds of tasks, EnDat 3 defines a background channel. Background communication is embedded in the foreground communication and uses its frames as transport carriers (REQ, LPH, LPF). The background channel thus makes it possible to read from and write to the encoder memory in the controller cycle. However, the background channel cannot handle real-time demands.
Along with point-to-point mode, EnDat 3 also offers bus operation for special applications. In bus operation, a Bus Request Frame is added in front of the Request Frame, thus allowing multiple participants to send responses in a single communication cycle.
EnDat enables extensive encoder monitoring and diagnostics without an additional wire. The interface’s diagnostics are an essential precondition for high complete-system availability. They generate the following aids:
- Valuation numbers
- Error messages
- Machine utilization planning
- On-site support for the service technician
- Easy evaluation of the encoder’s function reserve
- Simplified troubleshooting for repairs
- Generation of useful quality statistics
For analysis of encoder functionality, valuation numbers can be read cyclically from the encoder.
Valuation numbers do the following:
- Provide information about the current status of the encoder
- Allow an encoder’s function reserve to be determined
Their identical scaling for all HEIDENHAIN encoders enables consistent analysis.
The function reserves, combined with other sensor data, serve as the basis for condition monitoring and predictive maintenance in the higher-level subsequent electronics.