Section 2 Dnp 3.0 Overview; Dnp 3.0 Standard - ABB 615 Series Manual

1MRS756709 A
Section 2
2.1
615 series
Communication Protocol Manual
DNP 3.0 overview

DNP 3.0 standard

The DNP 3.0 protocol was developed by Westronic based on the early versions of
the IEC 60870-5 standard telecontrol protocol specifications. Now the protocol
specification is controlled by the DNP Users Group at
The ISO/OSI based model supported by this protocol specifies physical, data link and
application layers only. This reduced protocol stack is referred to as EPA. However,
to support advanced RTU functions and messages larger than the maximum frame
length as defined by the IEC document 60870-5-1, the DNP 3.0 data link is intended
to be used with a transport pseudo-layer. As a minimum, this transport layer
implements message assembly and disassembly services.
Physical layer
There are two physical layer modes specified; serial and serial tunneled over TCP/
IP.
Additional information on the DNP 3.0 physical layer is available at the DNP Users
Group at www.dnp.org
Data link layer
The DNP 3.0 data link layer is designed to operate with connection-oriented and
connectionless asynchronous or synchronous bit serial physical layers. Fully balanced
transmission procedures were adopted to support spontaneous transmissions from
outstations.
Data link functions:
• Performing message data link retransmissions.
• Synchronizing and handling of the FCB in the control octet.
• Setting and clearing the DFC bit based on buffer availability.
• Packing user data into the defined frame format, include CRC checksums and
transmitting the data to the physical layer.
• Unpacking the data link frame received from the physical layer into user data,
check and remove CRC checksums.
• Controlling all aspects of the physical layer.
• Responding to all valid frames received from the physical layer.
Data link responsibilities:
.
Section 2
DNP 3.0 overview
www.dnp.org .
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