Diagnostics of Networks

Area of application

SIMATIC PCS 7 communicates with the subordinate components of Totally Integrated Automation via Industrial Ethernet and PROFIBUS and uses the network components and communications processors (CPs) of SIMATIC NET. In addition to reliable communications, these also offer the facility for network diagnostics during runtime.

Benefits

  • High network availability through targeted and rapid localization of faults

  • Documentation of network activities for analysis and verification of network availability

  • Monitoring and improvement of the network capacity utilization

  • Automatic recognition of new or faulty participants

  • Integration of diagnostics data in automation and visualization systems

  • Detailed and clear graphical network representation


Design and functions

Industrial Ethernet Diagnostics – SCALANCE

SIMATIC PCS 7 process automation network is comprised of industrial Ethernet at the operator interface level using SCALANCE switches. In addition to reliable communication, they offer the facility for network diagnostics during operation using web-based tools.

The integral network management with the standard SNMP (Simple Network Management Protocol) in the SCALANCE X products provides diagnostics information. Using the SNMP OPC server present in the SIMATIC PCS 7 Maintenance Station, the diagnostics information from SCALANCE network components, Optical Switch Module (OSM) and Electrical Switch Module (ESM) can be accessed:

  • Status monitoring, device identification and network management of Scalance switches

  • Message to the operator if a network cable is un-plugged

  • Network overload

  • Loss of redundant power to the switch

  • Loss of network redundancy


Diagnostics of the PROFIBUS Network Using the Diagnostics Repeater

Bus cables are subjected to external forces that can cause damage. Particularly in the case of exceptional stress, e.g. trailing cables or strong vibrations, frequent inspection of the cables is recommended to reduce failures to a minimum.

The diagnostics repeater is available for cable diagnostics in such applications. It is integrated as a signal repeater into the PROFIBUS network, and has powerful functions for diagnostics of the following cable faults:

  • Open circuit in conductor A or B

  • Short-circuit between signal lines and the shield

  • Absent or too many bus terminating resistors

The diagnostics repeater is available for cable diagnostics in such applications. It is integrated as a signal repeater into the PROFIBUS network, and has powerful functions for diagnostics of the following cable faults:

  • The affected bus segment

  • The fault location (between stations X and Y), i.e. the distance of the fault location from the repeater to the stations in meters

  • The possible cause, e.g. short-circuit between signal cable A and shield.

This means that sporadic cable faults can be detected and signaled. The diagnostics functions also permit maintenance engineers without PROFIBUS experience, to rapidly and reliably locate faults in the bus cable.