Practical_modern_SCADA_protocols_-_dnp3,_60870-5_and_Related_Systems

212 Practical Modern SCADA Protocols: DNP3, 60870.5 and Related Systems
controlling stations. In these circumstances the originator address can be used to direct
command confirmations back to the particular controlling station that issued the command,
rather than to the whole system. The one exception to this is the originator address
of zero . This has the same effect as if there was no originator address. It is termed the
default address and its effect is that the message is transmitted to all stations. The use of
the originator address is discussed in greater detail under message addressing and routing.
COT
code
Cause of Transmission
0 Not used
1 Periodic, cyclic
2 Background scan
3 Spontaneous
4 Initialized
5 Request or requested
6 Activation
7 Activation confirmation
8 Deactivation
9 Deactivation confirmation
10 Activation termination
11 Return information caused by a remote command
12 Return information caused by a local command
13 File transfer
14–19 Reserved for future definitions
20 Interrogated by station interrogation
21–36 Interrogated by group (1–16) interrogation
37 Requested by general counter request
38–41 Requested by group (1–4) counter request
42–43 Reserved for future definitions
44 Unknown type identification
45 Unknown cause of transmission
46 Unknown common address of ASDU
47 Unknown information object address
Table 8.14
Cause of transmission codes (COT)