Two octets
Structured
Unstructured
Frame length
4095
Maximum length L (control direction)
255
Maximum length L (monitor direction)
Time during which repetitions are permitted (Trp) or number of repetitions
When using an unbalanced link layer, the following ASDU types are returned in
class 2 messages (low priority) with the indicated causes of transmission:
The standard assignment of ASDUs to class 2 messages is used as follows:
Type identification
Cause of transmission
A special assignment of ASDUs to class 2 messages is used as follows:
Type identification
Cause of transmission
In response to a class 2 poll, a controlled station may respond with
class 1 data when there is no class 2 data available.
3.7
Application layer
Transmission mode for application data
Mode 1 (Least significant octet first), as defined in 4.10 of IEC 60870-5-4, is used
exclusively in this companion standard.
Common address of ASDU
Section 3
1MRS757824 C
IEC 60870-5-101/104 protocol implementation
54
Recloser Protection and Control RER615
Point List Manual
