Technical description
6 Communication
6.2 Communication protocols
VM55.EN005
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6.2.5.
IEC 60870-5-103
The IEC standard 60870-5-103 “
Companion standard for the
informative interface of protection equipment” provides
standardized communication interface to a primary system
(master system).
The unbalanced transmission mode of the protocol is used, and
the device functions as a secondary station (slave) in the
communication. Data is transferred to the primary system
using “data acquisition by polling”-principle. The IEC
functionality includes the following application functions:
station initialization
general interrogation
clock synchronization and
command transmission.
It is not possible to transfer parameter data or disturbance
recordings via the IEC 103 protocol interface.
The following ASDU (Application Service Data Unit) types will
be used in communication from the device:
ASDU 1: time tagged message
ASDU 3: Measurands I
ASDU 5: Identification message
ASDU 6: Time synchronization and
ASDU 8: Termination of general interrogation.
The device will accept:
ASDU 6: Time synchronization
ASDU 7: Initiation of general interrogation and
ASDU 20: General command.
The data in a message frame is identified by:
type identification
function type and
information number.
These are fixed for data items in the compatible range of the
protocol, for example, the trip of I> function is identified by:
type identification = 1, function type = 160 and information
number = 90. “Private range” function types are used for such
data items, which are not defined by the standard (e.g. the
status of the digital inputs and the control of the objects).
