Communication link settings - Arc protection - Bay control and measurement - Motor protection - Transformer protection - 2 winding - Busbar differential protection (low impedance) - Feeder protection - Voltage regulation - Busbar protection (voltage and frequency) - Capacitor bank protection - Interconnection protection - Power management/Load shedding - Back-up protection - IEC 60870-5-101/104 Communication Manual - SSC600 Smart substation control and protection - 1.5 - IEC - ANSI - 19.04.2023

SSC600 and SSC600 SW IEC 60870-5-104 Communication Protocol Manual

Table 1. Communication link settings
Setting Description
Operation This enables the IEC 60870-5-104 protocol instance to work on the Ethernet link. This setting should be set to "On".
Client IP The IP address of the IEC 60870-5-104 client for which this instance is intended. Only a TCP connection request from this client IP address is accepted for this instance. If the IP address is set to 0.0.0.0, any client is accepted. In such a case, it is possible to distinguish between different clients through different TCP connection port socket configurations for each instance.
TCP Port TCP connection port socket used by this instance. The combination of the Client IP and TCP Port settings defines to which IEC 60870-5-104 client the instance is given.
Device address Device address of this IEC 60870-5-104 instance. The default setting of Link address length parameter is "1" octet, which enables only Device address values 1...255. 
ASDU address Standard “Common address of ASDU”. In most cases, this value should be the same as Device address. If it is set to another value, it may also have to be configured on the client side. The default setting of ASDU address length parameter is "1" octet, which enables only ASDU address values 1...255. 
Link mode Defines if the communication link is balanced or unbalanced. The default setting, balanced, is mostly used by IEC 60870-5-104 links. However, the unbalanced mode can also be used even though it is more common for serial IEC 60870-5-101 links.
COT length Length (number of octets used) of the Cause Of Transmission field. The default value is "2". The additional information included in the COT length = 2 alternative is however not supported by this IEC 60870-5-104 implementation.
IOA length Information Object Address field length (number of octets used) definition. This means the object addresses of IEC 60870-5-104 data points. The default setting is "3" octets. In Communication Management of PCM600, 16-bit addresses are supported. Consequently, if this setting is changed to "1", it must be ensured that no point addresses higher than 255 are defined.
Link address length Length (number of octets used) of the Link address field. The default setting is "2" octets. The length must match the configuration throughout the network. This field is filled with the Device address value.
ASDU address length Length (number of objects used) of the “Common address of ASDU” field. The default setting is "2". This must be equal to Link address length because Device address and “Common address of ASDU“ are equal. The length must also match the configuration throughout the network.
TX window (k) Sliding window protocol (k) transmit window setting. This is the maximum difference between the receive sequence and the send state variable, that is, the maximum number of outstanding I (information) format APDUs. The default setting is "12". The value range is 1...20.
RX window (w) Sliding window protocol (w) receive window setting. This is the maximum distance to the latest acknowledged I-format APDU. The default setting is "8". The value range is 1-20. The standard recommends that this setting should not exceed two thirds of the Tx window (k) setting.
TX timeout (t1) Timeout for confirmation of application or test APDU messages. The default setting is 30 seconds [30000 ms]. Adjustable between 1 ms and 60 s.
RX timeout (t2) Timeout for acknowledgements in case of no data messages. The default setting is 10 seconds [10000 ms]. Adjustable between 1 ms and 60 s. (t2) should be less than (t1).
Test interval (t3) Timeout for sending test APDU frames in case of long idle state (no line activity). The default setting is 20 seconds [20000 ms]. Adjustable between 1 ms and 60 s.