Profibus System Integration PDF 4.03MB - Schneider Electric

Overview of the main parts of the DFB:1. Analog input dataThis is a measurement data assigned to an array of 5 bytes, included in a DDTstructure. These bytes are derived from I/O data mapping.2. Measurement valueMeasured in format 32, this can be used by the program process loop, or can bedisplayed.3. Process StatusThese are the main status bits, used by the process sequence and to diagnose theprocess. The first part of the process status specifies the measurement quality, andthe second part provides the measurement thresholds.4. Display StatusThis is a DDT structure with complete status detail. This structure is intended fordisplay on SCADA or HMI.Diagnosis DFBReminderProfibus has a standard diagnostic and an extended diagnostic. The extendeddiagnostic is specific for each device.Performed functionThis DFB is designed to extract the details of a standard diagnostic; additionally,there is a specific implementation for the diagnostics data of each platform.This DFB is common to all our architectures. The only exception is the method forarranging the array of 6 bytes of data, which will be detailed in the ImplementationPhase chapter.48