User's Manual

DNP3 telecontrol protocol22

Operating modes

The DNP3 telecontrol protocol supports the following

operating modes (functional principle similar to that

described in the section for the SINAUT ST7 telecontrol

protocol):

•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

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 part-

ners 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 al-

lows 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 syn-

chronized via SIMATIC PCS 7 (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 trans-

mission (with dial-up networks or quantity-dependent

data transmission costs)