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IEC 870-5-101 communication protocol

Supported device types and versions 
Communication line configuration
Communication station configuration
Line protocol parameters
I/O tag configuration
Tell commands 
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


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

Parameter


Meaning


Unit


Default value


Link AddressCommon link address.-1
Length of ASDU AddressLength of ASDU address.1/2 byte(s)1
Length of Link AddressLength of common link address.1/2 byte(s)1
Length of Info Object AddressLength of info object address.1/2/3 byte(s)2
Length of Cause Of TransmissionLength of "Cause Of Transmission".1/2 byte(s)1
Retry CountDelay between request retry in case of a communication failure.-2
Retry TimeoutDelay between retry of call in case of communication error.ms100 millisecond
Wait First TimeoutDelay after sending the request before reading the response.ms100 millisecond
Wait TimeoutDelay between response readings till its completing.ms500 millisecond
Max. Wait RetryRetry count of response reading till its completing.-6
No Data TimeoutDelay of next call "Request user data class 1/2" if no data have been received (only master).ms300 millisecond
Inactivity TimeoutInterval of connection monitoring. If no valid data have not been received, station status will pass to communication error. Switching of redundant devices in case of SerialOverUDP Device Redundant line (only slave).ms5 sec.
Moxa TimeoutInterval of switching of the redundant devices MOXA NPort in case of communication error (only master, balanced).sec.10
Source FlagsSet flags FI..FL according to source of line. If SerialOverUDP System+Line Redundant is used, the values will have these flags:
  • System A, primary line: FI
  • System A, secondary line: FJ
  • System B, primary line: FK
  • System B, secondary line: FL

Note: Flag was used in communication with redundant systems to distinguish the wrong values that were sent by a partner system, which was supposed to be passive and not to send nothing.
-NO
No Output FlagsActivation of parameter results in ignoring of flags FA..FH for output I/O tags. If this parameter is turned off, flags FA..FH are mapped to individual bits of quality byte.-NO
Link Test TimeoutInterval of request sending "Test function for link" if timeout elapsed and no data telegrams was transferred (only balanced).sec.10
Single Value In Spontaneous AnswerWhen sending spontaneous changes, these will be sent one-per-ASDU and they will not be cumulated into longer packets. Parameter was implemented to handle a bug in a particular TM1703mic.-NO
Send Confirmation CommandType of sent confirmation to write value (only slave, balanced).-
7(CONF)
10(TERM)
7(CONF) and 10(TERM)
7(CONF)
Accept Confirmation CommandType of record confirmation to be accepted successfully (only master, balanced).-
7(CONF)
10(TERM)
7(CONF) or 10(TERM)
7(CONF) or 10(TERM)
Max. MTULimitation of data packet size (only slave, balanced).bytes220
Phys. Trans. DirectionSetting a bit DIR in balance mode (only balanced).Station A(Controlling)
Station B(Controlled)
Station A(Controlling)
Single Byte AckSend single-byte ACK preferentially (0xE5).YES/NONO
Interrog. Covers CountersSend the call 100 and counter values on general interrogation (only slave, balanced).YES/NOYES
Send EOISend "end of interrogation command" to all ASDU (only slave).YES/NOYES
Send Interrog. in Sec. Direct.Send general interrogation command in case of slave or balanced controlled station B (only slave, balanced).YES/NONO

Sinaut Mode

Communication for system Sinaut Spectrum, which requires non-standard behavior on redundant lines (different from the Norwegian convention).YES/NONO

System Redundancy: Manages A Status Address

-
Full DebugHigh level of communication tracking, the loaded values of I/O tags and other debug information are shown.YES/NONO

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:

ASDU typeI/O Tag type
45 - Single commandDout
46 - Double commandDout, Co
47 - Regulating step commandDout
48 - Set point command, normalised valueAo
49 - Set point command, scaled valueCo
50 - Set point command, short floating point valueAo
51 - Bitstring of 32 bitCo
58 - Single command with time tag CP56Time2aDout
59 - Double command with time tag CP56Time2aDout, Co
60 - Regulating step command with time tag CP56Time2aDout
61 - Set point command, normalised value with time tag CP56Time2aAo
62 - Set point command, scaled value with time tag CP56Time2aCo
63 - Set point command, short floating point value with time tag CP56Time2a Ao
64 - Bitstring of 32 bit with time tag CP56Time2aCo

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

ASDU typeI/O Tag type
1 - Single-point informationDi, Qi (On/Off), Ai, Ci
2 - Single-point information with time tagDi, Qi (On/Off), Ai, Ci
3 - Double-point informationQi, Ai, Ci
4 - Double-point information with time tagQi, Ai, Ci
5 - Step position informationCi, Ai *
6 - Step position information with time tagCi, Ai *
7 - Bitstring of 32 bitsCi, Ai
8 - Bitstring of 32 bits with time tagCi, Ai
9 - Measured value, normalized valueAi
10 - Measured value, normalized value with time tagAi
11 - Measured value, scaled valueCi, Ai
12 - Measured value, scaled value with time tagCi, Ai
13 - Measured value, short floating point valueAi
14 - Measured value, short floating point value with time tagAi
15 - Integrated totalsCi, Ai
16 - Integrated totals with time tagCi, Ai
17 - Event of protection equipment with time tagCi, Ai, TiR **
18 - Packed start events of protection equipment with time tagCi, Ai, TiR ***
20 - Packed single-point information with status change detectionCi, Ai
21 - Measured value, normalized value without quality descriptorAi
30 - Single-point information with time tag CP56Time2aDi, Qi (On/Off), Ai, Ci
31 - Double-point information with CP56Time2a tagQi, Ai, Ci
32 - Step position information with CP56Time2a tagCi, Ai *
33 - Bitstring of 32 bits with CP56Time2a tagCi, Ai
34 - Measured value, normalized value with CP56Time2a tagAi
35 - Measured value, scaled value with CP56Time2a tagCi, Ai
36 - Measured value, short floating point value with time tag CP56Time2aAi
37 - Integrated totals with time tag CP56Time2aCi, Ai
38 - Event of protection equipment with time tag CP56Time2aCi, Ai, TiR **
39 - Packed start events of protection equipment with time tag CP56Time2aCi, Ai, TiR ***
40 - Packed output circuit information of protection equipment with time tag CP56Time2aCi, Ai, TiR ***

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 (of integer and real type). Name of this I/O tag has this format: [name of line]_SystemStatus (e.g. for line L.Test it is M.Test_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 (SystemB/SecondaryLine) i.e. [FALSE,TRUE,TRUE,TRUE], I/O tag has the value 0b0111, i.e. 7.
The order of lines mapped to individual bites is [SystemB/SecondaryLine,  SystemB/PrimaryLine, SystemA/SecondaryLine, SystemA/PrimaryLine].

Tell commands


CommandSyntaxDescription
STWATCHSTWATCH StationNameTell command sends Interrogation Command (if it is configured/permitted for specific protocol).


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.


Blogs

You can read blogs about  IEC 870-5-101 protocol (for now, in Slovak language only): 


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
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