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Digital Sub-station - Coggle Diagram
Digital Sub-station
IEC 60870
Asia, Europe, Middle East
IEC 60870 Part-5
Transmission Protocols
IEC 60870-5-101
RS‑485/RS‑232, FSK, Powerline
Addressing
Link address (L‑address)
Application addresses inside ASDU
ASDU
(Application Service Data Unit)
Type ID
Monitoring
M_SP_NA_1: Single Point Information (no time tag)
M_DP_NA_1: Double Point Information
M_ME_NA_1: Meas. value, normalized (no time tag)
M_ME_NB_1: Meas. value, scaled
M_ME_NC_1: Meas. value, short float
Time‑tagged versions (e.g., M_SP_TB_1, M_ME_TD_1) include CP56Time2a.
Commands
C_SC_NA_1: Single command (e.g., trip/close)
C_DC_NA_1: Double command
C_SE_NA_1/…: Set‑point commands (normalized, scaled, float)
Each with activation / deactivation / confirm COT sequences.
Interrogations and control
C_IC_NA_1: General interrogation
C_CI_NA_1: Counter interrogation
C_CS_NA_1: Clock synchronization
C_RP_NA_1: Reset process command
Cause of Transmission (COT)
3: Spontaneous – a data change detected by RTU and sent without being asked.
1, 2: Periodic / background scans (cyclic data).
20: General interrogation (GI) activation
21: GI confirmation
22: GI termination
6, 7: Activation / activation confirmation for commands.
10: Remote command (control center issued).
15: Clock synchronization.
Common Address of ASDU (CA)
Information Objects (IO)
Communication modes
Polling
spontaneous
General Interrogation (GI)
Counter interrogation
Communication Protocol Layers
Layer-2
Frame Formats
Variable‑length Frame (primary data frame)
Transparent/Special Frames
Single‑character ACK (E5h)
Fixed‑length Frame
Control Field (Link Layer)
IEC 60870-5-104
TCP/IP over LAN/WAN
No Authentication
Protocol Stack
Application Layer
APDUs
(Application Protocol Data Units)
APDU = APCI + ASDU
S‑frames
(Supervisory numbering acknowledgment)
Used for flow control and acknowledgement (when no user data needs to be sent).
U‑frames
(Unnumbered control functions)
Used for control of the link:
STARTDT (start data transfer)
STOPDT (stop data transfer)
TESTFR (link test)
I‑frames
(Information frames)
Carry ASDUs (measurements, indications, commands, events).
ASDU
(Application Service Data Unit)
Cause of Transmission (COT)
3: Spontaneous – a data change detected by RTU and sent without being asked.
1, 2: Periodic / background scans (cyclic data).
20: General interrogation (GI) activation
21: GI confirmation
22: GI termination
6, 7: Activation / activation confirmation for commands.
10: Remote command (control center issued).
15: Clock synchronization.
Common Address of ASDU (CA)
Information Objects (IO)
Type ID
1 to 125
https://www.freyrscada.com/iec-60870-5-104.php
M Monitoring
C
(Control)
S
(System)
P
(Parameter)
F
(File)
Monitoring
6 more items...
Command / Control
4 more items...
Interrogations and control
4 more items...
APCI
(Application Protocol Control Information)
Transport Layer
TCP: Port 2404
IOA
Information Object Address
IEC 62351 profiles (for secure IEC 60870‑5‑104), adding TLS and role‑based access control.
Client/Server Model
Execute
Select-Before-Operate (SBO)
Direct-Execute
IEC 60870-5-1 Transmission Frame Formats
IEC 60870-5-2 Link Transmission Procedures
IEC 60870-5-3 General Structure of Application Data
IEC 60870-5-4 Definition and Coding of Application Information Elements
IEC 60870-5-5 Basic Application Functions
IEC 60870-5-6 Guidelines for conformance testing for the IEC 60870-5 companion
standards
IEC TS 60870-5-7 Security extensions to IEC 60870-5-101 and IEC 60870-5-104 protocols
(applying IEC 62351)
IEC 60870-5-102 (1996) Transmission Protocols
IEC TS 60870-5-601 Transmission protocols
IEC TS 60870-5-604 Conformance test cases
IEC 60870 Part-1
General Considerations
Part 2
Operating Conditions
Part 3
Interfaces
Part 4
Performance Requirements
Part 6
Telecontrol Protocols Compatible with ISO & ITU-T
IEC 61850
GOOSE
SCL
System Configuration Language
Information Models
Logical Nodes (LNs)
Part 7-4
Circuit Breaker (XCBR)
Time Over Current Protection (PTOC)
Power System Measurement (MMXU)
Generic APplication Logic (GApC)
Logical Devices (LDs)
Data Objects (DOs)
Data Attributes (DAs)
Communication models
Configuration & Engineering
SCL
(Substation Configurtion Language)
Part 6
XML file
ICD
IED Capability Description
IID
Instantiated IED Description
SCD
System Configuration Description
Config Tools
SCT
System Configuration Tool
ICT
IED Configuration Tool
Networking
Towards SCADA
Other Sub-station
LAN
Station Bus Topolgy
Station Level
Bay Level
Process Level
Devices
Functional
Circuit Breakers
CTs
PTs
Transformers
Monitoring / Controlling
RTUs
IEDs
Communication Protocol Stack
High Speed Traffic
(Layer 2)
GOOSE
(Generic Object Oriented Sub-station Event)
Tripping / Inter-locking functions
Event Driven / Time Critical
Multicast (Layer 2)
SVs (Sampled Values) Part 9-2
Voltage / Current Samples
Process Bus Traffic
Multicast (Layer 2)
Standard Traffic
MMS
(Manufacturing Message Specification)
Organizations in the domain
International
Elseta
Indian
PTP
IEC 62351-5
Security
DNP3
Americas, South Africa, Australia