Management by Exception

 

 

Management by exception or PUSH technology is a requirement of isolated systems or intermittent communications. This kind of technology enables the M2M device to start communications without any previous poll, so it can stay in “sleep” mode and communicate only when it’s really necessary. This allows bandwidth savings in communications, traffic and energy consumptions.

There are standard communication protocols for telemetry, remote control and M2M networks, such as DNP3, based on an open, public domain architecture, including many features specifically applied to these projects. For example, the DNP3 Users Group states these features of DNP3 as the main ones:

  • Management by exception (answer without unsolicited question or spontaneous message)
  • Question and answer with multiple data in simple messages
  • Message segmentation in multiple frames to ensure answer messages (report-per-exception)
  • Assign priorities to items and periodical questions depending on priority
  • Support to time synchronization and standard time format
  • Enables multiple masters and peer-to-peer operations
  • Enables user-defined objects, including file transfer
  • Security