IEC 870-5-101 communication protocol

Supported device types and versions 
Communication line configuration
Communication station configuration
Line protocol parameters
I/O tag configuration
Literature
Changes and modifications
Document revisions

Supported device types and versions

Protocol supports:

• standard IEC 60870-5-101:2003 in modes "unbalanced" (master and slave) and "balanced",
• redundancy of communication lines according to so-called Norwegian convention (Norwegian IEC 870-5-101 User Conventions).

Communication line configuration

• Line categories: Serial, Serial Line Redundant, SerialOverUDP Device Redundant, SerialOverUDP Line Redundant or SerialOverUDP System&Line Redundant.

Implementation is, according to the IEC870-5-101 standard, as follows:

• Originator ASDU address is not present.
• ASDU address is 1 byte, it is defined as the station address. ASDU addresses of all stations on one line must be different.
• Cause of transmission is 1 byte (does not contain Originator ASDU address).
• Information object address is 2 bytes, it is defined as an I/O tag address.

If a redundant communication on two lines is required (Norwegian conventions) use the line categories Serial Line Redundant or SerialOverUDP Device Redundant.

If you require the system-redundant communication, use the line category SerialOverUDP System&Line Redundant. Providing that, this communication should be also network redundant, enter "Secondary line" for both "A System" and "B System". This configuration then works in such a way that it concurrently sends and receives data from two systems and each is network-redundantly connected in compliance with so-called Norwegian convention (Norwegian IEC 870-5-101 User Conventions).

Communication station configuration

• Communication protocol "IEC 870-5-101 balanced", "IEC 870-5-101 unbalanced primary (Master)" or "IEC 870-5-101 unbalanced secondary (Slave)".
• Station address is a decimal number in range 0 - 255 and is used in protocol as the ASDU address.
• The synchronization of the station real-time may be enabled also for the protocols "master" and "balanced - station A (controlling)". Set the synchronization period to nonzero value. The synchronization is executed by ASDU 103 "Clock synchronization command" in the local time according to settings of D2000 System.

Line protocol parameters

Configuration dialog box - tab Protocol parameters.
They influence some optional parameters of protocol. Following station protocol parameters can be set:

Table 1

I/O tag configuration

Possible value types of I/O tags: Ai, Ao, Di, Dout, Ci, Co, Qi

I/O tag address is numerical address of data object IOA (in range 0 - 65535).

In case of command direction in master or balanced mode is necessary to configure je proper ASDU type:

In case of slave or balanced mode je is necessary to configure je proper ASDU type in v data direction:

Note 1: Individual bits of bytes which determines a quality (SIQ for ASDU 1,2,30; DIQ for ASDU 3,4,31; QDS for 5-14,20,32-36) set the attributes FLA (0.bit), FLB (1.bit) ..FLH (7.bit).
Example:
for ASDU 4 : FLA=DPI bit 0, FLB=DPI bit 1, FLC=0, FLD=0, FLE=BL bit, FLF=SB bit, FLG=NT bit, FLH=IV bit.
for ASDU 16 : FLA..FLE Sequence number bity 0..4, FLF=CY bit, FLG=CA bit, FLH=IV bit

And:

• if bit IV (Invalid) is set, status of value will be Invalid
• if one of bits NT (Not topical), SB (Substituted), BL (Blocked), OV (Overflow), CA(Counter adjusted), CY(Counter overflow) is set for proper ASDU types, status of value will be Weak.

* - T-bit from value of ASDU sets the attribute FI into value of I/O tag which has value type Ci/Ai and they are interpreted as figures -64 up-to +63.

** - ASDU 17 and 38: value of byte SEP sets the attributes FLA (0.bit), FLB (1.bit) up-to FLH (7.bit), following 2 bytes (CP16Time2a) are interpreted as positive number (0-60 000) into value of I/O tag with value type Ci/Ai or as relative time (0-60 seconds) into value of I/O tag with value type TiR.

*** - ASDU 18, 39 and 40: value of byte SPE(ASDU 18,39) or OCI (ASDU 40) sets the attributes FLI (0.bit), FLJ (1.bit) up-to FLP (7.bit). Value of byte QDP sets the attributes FLA (0.bit), FLB (1.bit) up-to FLH (7.bit), following 2 bytes (CP16Time2a) are interpreted as positive number (0-60 000) into value of I/O tag with value type Ci/Ai or as relative time (0-60 seconds) into value of I/O tag with value type TiR.

Note 2: When using the system and line redundant categories of lines, the status of line and station is formed by a logical sum of all used elements. It means, that if the redundant system consists of four lines and just one line is working, status of station and line is all right. The status of lines is presented with the help of special output I/O tag (integer and real type). Name of this I/O tag has this format: [name of line]_SystemStatus. The value of I/O tag represents binary format of status of N-tuple lines. If the first three lines are okay but the last one does not work [FALSE,TRUE,TRUE,TRUE], I/O tag has the value 0b0111, i.e. 7

Literature

• Telecontrol equipment and systems Part 5-101: Transmission protocols – Companion standard for basic telecontrol tasks (IEC 60870-5-101:2003), http:\\www.iec.ch.
• Telecontrol equipment and systems Part 5-2: Link transmissions procedures (IEC 60870-5-2:1992), http:\\www.iec.ch.
• Norwegian IEC 870-5-101 User Conventions, Approved version Revision no. 2.0, http:\\www.statnett.no.

Changes and modifications

• June, 2015 - implemented Source Flags parameter

Document revisions

• Ver. 1.0 - November 22nd, 2007 - document creating
• Ver. 1.1 - April 22nd, 2009 - document updating
• Ver. 1.2 - June 8th, 2015 - new parameter implemented