Technical Guide P92x/EN CT/E11
IEC 60870-5-103
MiCOM P921-P922-P923 Page 109/118
4. IEC60870-5-103 INTERFACE
The IEC60870-5-103 interface is a master/slave interface with the relay as the slave
device. This protocol is based on the VDEW communication protocol. The relay
conforms to compatibility level 2, compatibility level 3 not supported.
The following IEC60870-5-103 facilities are supported by this interface:
· Initialization (Reset)
· Time synchronization
· Event Record Extraction
· General Interrogation
· Cyclic Measurements
· General Commands
4.1 Physical Connection and Link Layer
Connection is available for IEC60870-5-103 through the rear RS485 port. It is
possible to select the relay address and baud rate using the front panel interface.
Following a change, a reset command is required to re-establish communications.
The parameters of the communication are the following:
· Even Parity
· 8 Data bits
· 1 stop bit
· Data rate 9600 or 19200 bauds.
4.2 Initialization
Whenever the relay is powered up, or when the communication parameters are
modified, a reset command is required to initialize the communications. The relay
will respond to either of the two reset commands (Reset CU or Reset FCB), the
difference being that the Reset CU will clear any message which is not sent in the
relay’s transmit buffer.
The relay will respond to the reset command with an identification message ASDU5,
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 following information will be
contained in the data section of this ASDU:
Manufacturer Name : AREVA
The Software Identification Section will contain the first four characters of the relay
model number to identify the type of relay, e.g. P923.
In addition to the above identification message, if the relay has been powered up, it
will also produce a power up event.
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