The configuration and programming software package is required to set up a Profibus network.
Diagnostic trouble rectification includes process related responses, built-in diagnostics mechanisms to indicate troubles on SCADA or PLC, and a Profibus interfacing break-through cable itself. Continuous monitoring of Profibus communication can identify some of the critical problems before they lead to major production loss. The diagnostics from different devices are event-triggered and generate a recordable alarm report.
Generally an engineer needs two tools to rectify the errors in network: a bus analyzer to determine the protocol quality and an oscilloscope to confirm the signal quality of the data communication, e.g. short circuit, wire breaks, termination error, etc.
A short circuit in the Profibus cable will disconnect the data communication from the master. The instrument on that node will not be destroyed in this case. The short circuit and the distance to the trouble point can be detected with an oscilloscope.
Diagnostic Function Blocks
Function blocks are capable of diagnosing each slave device. The diagnostic information can be stored in a data block. This data block further can be displayed on a SCADA PC.
The repeater acts as a slave on the network and can interface diagnostics information to the master. This diagnostic data contains various fault types like Profibus cable break, conductor short circuit with the shield, terminator resistor break, nodes diagnostics, etc. The location and type of the fault on the cable can be identified in text and a graphical representation.
Power Cable Disturbance
Profibus interfacing can be disturbed by interference caused by a power cable laid near the Profibus cables. At least 10 cm air space between the Profibus and power cable should be maintained. Also proper shielding is important to prevent interference.