Practical_modern_SCADA_protocols_-_dnp3,_60870-5_and_Related_Systems

Applications of DNP3 and SCADA protocols 379
Network-to-network bridges
ASCII communications to LCD or hand-held display units
ASCII communications to smart instruments
PDS to computer connections are :
• DNP3 configuration software
Utility for setting up and diagnostics, it uses either the DIAG port or other
RS-232 serial ports using DNP3 protocol
• Terminal diagnostics
Terminals or PCs with terminal emulation software, such as HyperTerminal,
can intercept the ASCII characters being sent on the network through either
the DIAG port on a PDS500 or port 0 on a PDS Compact 500. This facility is
also used by the PDS firmware to interact in the process of I/O calibration
• ISaGRAF software
IEC 61131-3 PLC programs can be downloaded to an RTU or debugged on
site with a laptop and a serial cable usually connected to port 1 or port 0 as
configured
• PDS to computer network
The PDS104 Gateway or PDS Compact eNET RTU support TCP/IP allowing
connectivity of PDS RTU networks to Internet or intranet wide area networks,
or local area computer networks
15.1.5 DNP3 configuration aspects
The implementation of DNP3 protocol is described briefly here by the manufacturer. Note
that the RTU devices provide support for networked transmission of DNP3 frames as well
as standard direct asynchronous transmission.
Introduction to DNP3
DNP3 (distributed network protocol) is an industry standard SCADA communications
protocol. It originated in the electricity industry in the USA and was based on drafts of
the IEC870-5 SCADA protocol standards (now known as IEC 60870-5). DNP3 is now
in widespread use in many industries across the world and is managed by the DNP3 User
Group.
DNP3 describes standards for SCADA protocol facilities such as data requests, polling,
controls, and report by exception (RBE). Master–slave and peer-to-peer communication
architectures are supported by DNP3.
Inter-operability is one of the key aspects of DNP3. It is enforced by way of minimum
implementation sub-sets to which vendors must adhere. Currently, the DNP3 standard
is supplemented by a sub-set definitions document describing 3 minimum sub-set levels.
In addition, a vendor’s DNP3 implementation must be provided with a device profile
document describing information required by the DNP3 User Group, including details
of the implementation of one of the three minimum sub-set levels, and other protocol
information.