2.2.2  Physical Connection and Link Layer 
There are two options available for connecting on IEC 60870-5-103: 
•  Front USB port 
•  Rear serial port 1- for permanent SCADA connection via RS485 
 
The IED address and baud rate can be selected using the front panel menu or with P50 Agile 
configurator. 
2.2.3  Initialisation 
Whenever the device has been powered up, or if the communication parameters have been changed, 
a reset command is required to initialize the communications. The device will respond to either of the 
two reset commands; Reset CU or Reset FCB (Communication Unit or Frame Count Bit). The 
difference between the two commands is that the Reset CU command will clear any unsent messages 
in the transmit buffer, whereas the Reset FCB command does not delete any messages. 
The device will respond to the reset command with an identification message ASDU 5. The Cause of 
Transmission (COT) of this response will be either Reset CU or Reset FCB depending on the nature of 
the reset command. 
The relay will also produce a power up event, when the relay is powered up. 
2.2.4  Time Synchronisation 
The time and date can be set using the time synchronisation feature of the IEC 60870-5-103 protocol. 
The device will correct the transmission delay depending on communication speed. For this, 
transmission time, required for the time synchronization frame from the Master to IED, considering 
current baud rate is added in the received time.  
The device will correct the transmission delay depending on baud rate. If the time synchronisation 
message is sent as a send/confirm message then the device will respond with a confirm message. A 
time synchronisation Class 1 event will be generated/produced whether the time-synchronisation 
message is sent as a send confirm or a broadcast (send/no reply) message. 
2.2.5  Spontaneous Events 
Events are categorized using the following information: 
•  Function type 
•  Information Number 
 
The IEC 60870-5-103 profile contains a complete listing of all events produced by the device. 
2.2.6  General Interrogation (GI) 
The GI request can be used to read the status of the device, the function numbers, and information 
numbers that will be returned during the GI cycle. These are shown in the IEC 60870-5-103 profile. 
2.2.7  Cyclic Measurements 
The device will produce measured values using ASDU9 and ASDU9 is reported with information 
number 148 and 155. This can be read from the device using a Class 2 poll. For every query, the 
current online data is reported. 
The device transmits its measurands at 2.4 times the rated value of the analogue value.