Special characteristics of DNP3 communication
- Change-driven data transmission
- Change-driven transmission of process data between RTU and control center
- Signaling of RTU, control center or connection failure
- Automatic data updating for all communication partners involved following troubleshooting and following the startup of the RTU or control center
- Chronological processing of process data
- Time tagging of all data frames at the place of origin allows process data to be archived by the process control system in the correct chronological order
- The time of the DNP3 stations in the WAN can be synchronized via SIMATIC WinCC (including summertime/wintertime switchover)
- Local data storage
- The TIM communication module can temporarily store (for several hours or even days) message frames should the connection or the communication partner fail
- Intermediate storage of message frames of lower priority in the case of priority-controlled data transmission (with dial-up networks or quantity-dependent data transmission costs)
Operating modes
The DNP3 telecontrol protocol supports the following operating modes:
- Polling
- Polling with time slot procedure
- Multi-master polling with time slot procedure
- Spontaneous mode in dial-up networks
- Spontaneous mode in the TCP/IP-based WAN