General

Communication Driver Name: IEC8705104S
Current Version: 9.2
Implementation DLLC: T.ProtocolDriver.IEC8705104S.dll
protocol: IEC-60870-5-104 Slave standard protocol
Interface: TCP/IP
Description: The IEC870504S protocol implements communication with client stations compatible with this protocol, acting as a slave station (server).
Clients types supported: Any IEC-60870-5-104 compliant customer.
Communication block size: Maximum 253 bytes;
Protocol Options: Timers for sending protocol control messages.
Threading: User-configurable, default is five threads for each node in the network.
Max number of nodes: user-defined
PC Hardware Requirements: Standard PC Ethernet interface board;
PC Software requirements: ActionNET system.

Supported Data Objects (ASDUs)

The protocol uses the same ASDUs defined for IEC-60870-5-101 as well as the same types of data objects. The big difference is to be oriented to network use, using TCP-IP as a transport layer.
M_SP_NA: 1 - Single-point information ;
M_DP_NA: 3 - Double-point information ;
M_ST_NA: 5 - Step position;
M_BO_NA: 7 - Bitstring with 32 bits ;
M_ME_NA: 9 - Measured value, normalized ;
M_ME_NB: 11 - Measured value, scaled value ;
M_ME_NC: 13 - Measured value Float;
M_IT_NA: 15 - Integrated totals ;
C_SC_NA: 45 - Single command ;
C_DC_NA: 46 - Double command ;
C_RC_NA: 47 - Regulating step command ;
C_SE_NA: 48 - Set point command, normalized value ;
C_SE_NC: 50 - Set point command, 32-bit floating point;
C_BO_NA: 51- Write Bitstring 32-bit;

And also all variants with a 56-bit timestamp of the ABOVE ASDUs. In the registration of points, the above codes are used, but when sending unsolicited changes are used the variants with date and timestamp are obtained from the tags currently in memory.

General operation

The IEC-60870-5-104 protocol is implemented in Slave (server) mode by communicating with client stations implementing the master IEC-870-5-104 protocol. Several parameterizations are available to accommodate different profiles of protocol implementations.
Slave mode has the following basic operating sequence:

• At the beginning (or after closing the Tcp-Ip socket) is in a DISCONNECTED state (and with the socket in LISTENING state) waiting for a TCP-IP connection from a client.

• When connected, you go to an ESTABLISHED state not responding or sending any message until you receive a "Start of data transmission - STARTDT" message;

• Upon receiving this message it responds with START-DT Confirmation and passes to the STARTED state, ready to receive and send any of the implemented messages.

• Sends unsolicited messages of data from objects that have changed status in the field.

• For each "k" (configurable parameter) message sent, or after some time without sending messages, wait for a message of "acknowledgment" with the sequence number of the last information message received by the client. If you do not receive this "ack" go to the "UNCONF STOPPED" state.

• Always responds to "Test Frames" messages with confirmation.

This module responds to requests to read variables - analog and digital - event transmission and command execution. The implementation has the following characteristics:

• Responds to cyclic reading requests (general sampling) of single/double and analog-digital points;

• Spontaneously sends changes to digital point states and changes in analog measures, considering dead band and time for integrity.

• Uses a 56-bit-long time tag.

• Accepts commands for single and double digital points;

• Supports direct command or select before operating;

• It does spot quality treatment (QDS);