IEC 60870-5-101

IEC 60870-5-101 (also known as IEC 870-5-101) is an international standard, released at the beginning of the 90ies by  the IEC (International Electrotechnical Commission). The protocol has found widespread use in the energy sector, and is still used today. It is based on the EPA architecture (Enhanced Performance Architecture) and defines only the physical link and application layers of the OSI model.

IEC 60870-5-101 is primarily used with relatively slow transmission media on the asynchronous V.24 interface. The standard promises baud rates of up to 9600 bit/s, with much higher baud rates (<115200 bit/s) actually being used. X.24/X.27 interfaces with baud rates up to 64000 bit/s, also part of the standard's description, could not establish themselves and are rarely used.

IEC 60870-5-101 is a 'Companion Standard', extended by these further standards:

  • IEC 60870-5-1
    defines different frame formats, though IEC 60870-5-101 uses only the FT1.2 format
  • IEC 60870-5-2
    defines the link layer transmission mode
  • IEC 60870-5-3
    defines the basic application data structure
  • IEC 60870-5-4
    defines how information is encoded
  • IEC 60870-5-5
    defines basic application layer functions
  • IEC TS 60870-5-601
    defines "Conformance Test Cases" for IEC 60870-5-101

IEC 60870-5-101 was extended and more precisely defined in 2001 by Amendment 2.

Interoperability between devices by different vendors is ensured by the interoperability list, which is defined by the standard. In the list, the function range is defined for each device by marking the applicable functions. The common denominator between different vendor lists limits the possible function range.

As the original standard left more room for interpretation, there were many different implementations on a wide range of different devices many of which are mutually incompatible. To remedy this situation, major energy utilities, such as RWE, Bayernwerke (E.ON), have developed their own IEC 60870-5-101 based standards. The "Norwegian IEC 870-5-101 User Convention", managing line redundancy in particular, has found wide acceptance in Scandinavian countries.

IEC 60870-5-101 is known for the resilience of its link layer and for its simply structured application layer. The main focus was placed on on performance definition, so that some information needed for data decoding is not transmitted. For data decoding to work, parameter settings such as information object length, ASDU address length etc. need to be correct. This is not much of a problem, as interoperability lists help to achieve this.

Fragmentary protocol definition has its disadvantages, especially with respect to line redundancy where a range of diverging implementations exist. A clear definition of project-specific requirements is recommended.

In addition to standard protocol functionalities, IEC 60870-5-101 also allows for extensions with proprietary vendor-specific functions. Though not used too often, this also carries the risk of incompatibilities.
 

ISO/OSI Model

7 Application Layer IEC 60870-5-101 Companion Standard
IEC 60870-5-5, IEC 60870-5-4, IEC 60870-5-3
6 Presentation Layer n/a
5 Session Layer n/a
4 Transport Layer n/a
3 Network Layer n/a
2 Link Layer balanced
IEC 60870-5-2
IEC 60870-5-1 (FT 1.2)
unbalanced
IEC 60870-5-2
IEC 60870-5-1 (FT 1.2)
1 Physical Layer RS232 (V.24)X.24/X.27

Supported Information Types

Control Direction
  • Single Command
  • Double Command
  • Setpoint
  • Regulating step command
Monitoring Direction
  • Single indication [1 Bit] with quality
  • Single indication [1 Bit] with quality and time tag
  • Double indication [2 bit] with quality
  • Double indication [2 bit] with quality and time tag
  • Measured scaled value with quality
  • Measured scaled value with quality and time tag
  • Measured normalized value with quality
  • Measured normalized value with quality and time tag
  • Measured floating point value with quality
  • Measured floating point value with quality and time tag
  • Bitpattern [32 bit] with quality
  • Bitpattern [32 bit] with quality and time tag
  • Counter value with quality
  • Counter value with quality and time tag
  • Step position value with quality
  • Step position value with quality and time tag
  • Event of protection equipment with quality and time tag

Protocol Features

  • Physical Layer

    PCM, Full-duplex operation in balanced mode, half-duplex operation in unbalanced mode

  • Link Layer

    Asymmetric transmission (unbalanced mode): Party line or point to point
    Symmetric transmission (balanced mode): Only point to point is possible

  • Application Layer

    On-demand transmission (e. g. single indications, analogs, ...)
    Spontaneous transmission (e. g. single indications with time tag, ...)
    Direct command transmission (with select before operate)
    Clock synchronization
    File Transfer

  • Address Space

    Common Address of ASDU: 1..65535
    Information object address: 1..16777215
    Link address: 0..65535

Implemented Protocol Stacks

IEC 60870-5-101, Dialup Master

IEC 60870-5-101, Master

IEC 60870-5-101, Slave

Applicable Products

  • ipRoute
    ipRoute

    Router for IEC 870-5-101 and IEC 870-5-104 protocols
    start price 970,- €

  • ipRouteDialup
    ipRouteDialup

    IEC 870-5-101 router to connect RTUs and SCADA systems over dialup lines

  • ipConvLite
    ipConvLite

    inexpensive protocol converter for standardized application

  • ipConvOPC
    ipConvOPC

    Softwarepackage for conversion between OPC DA 3.0 Server and standard protocols

  • ipConvPBS
    ipConvPBS

    Universal protocol converter with integrated PROFIBUS-DP, slave interface

  • ipConvPBM
    ipConvPBM

    Universal protocol converter with integrated PROFIBUS-DP, master interface

  • ipConvPNM
    ipConvPNM

    Universal protocol converter with integrated PROFINET-IO, master interface

    Available soon !
  • ipConvPNS
    ipConvPNS

    Universal protocol converter with integrated PROFINET-IO, slave interface

  • ipConv
    ipConv

    Universal protocol converter for highest degree of flexibility

  • Fink WinPP Protocol Simulator
    Fink WinPP Protocol Simulator

    Simulationsoftware for IEC 60870-5-101, IEC 60870-5-102, IEC 60870-5-103, IEC 60870-5-104, SINAUT 8-FW 16-1024 PCM/DPDM

References

  • Ballia-Bhiwadi
    Ballia-Bhiwadi, India

    Products: ipConv
    Protocol Stacks: IEC 60870-5-101, Master IEC 60870-5-101, Slave Simatic TDC, Master

  • SEC SVC
    SEC SVC, Saudi Arabia

    Products: ipConv
    Protocol Stacks: IEC 60870-5-101, Slave IEC 60870-5-104, Slave IEC 61850, Client Simatic TDC, Master

  • I-SHAPE
    I-SHAPE, Thailand

    Products: ipConv
    Protocol Stacks: IEC 60870-5-101, Slave XMAT, Master

  • BLS AlpTransit - Lötschbergtunnel
    BLS AlpTransit - Lötschbergtunnel, Switzerland

    Products: ipConv ipRoute
    Protocol Stacks: OPC DA 3.0, Server IEC 60870-5-104, Slave IEC 60870-5-101, Master IEC 60870-5-104, Master SNMP, Client

  • Mainova Communication Hub
    Mainova Communication Hub, Germany

    Products: ipConv
    Protocol Stacks: OPC DAXML 1.01, Server IEC 60870-5-104, Slave IEC 60870-5-101, Master Modbus, Master SEAB 1F, Master

  • FSC HECHI
    FSC HECHI, China

    Products: ipConv
    Protocol Stacks: SC1801, Slave IEC 60870-5-104, Slave IEC 60870-5-101, Slave Simadyn-D, Master

  • FRANKENDATA
    FRANKENDATA, Germany

    Products: ipConv
    Protocol Stacks: IEC 60870-5-101, Master SISA, QD2 Slave