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Causes of Transmission |
A Cause of Transmission is an information that is part of an ASDU sent or received in protocol IEC 870-5-104, and indicates the reason why that ASDU is being sent or requested. The most common values for Cause of Transmission are listed on the next table.
Values for Cause of Transmission in protocol IEC 870-5-104
Meaning |
Cause of Transmission |
Negative Transmission (Sum 64) |
Test Transmission (Sum 128) |
|---|---|---|---|
Cyclic sending (CYC) |
1 (one) |
65 |
129 |
Background sending (BACK) |
2 (two) |
66 |
130 |
Spontaneous sending (SPONT) |
3 (three) |
67 |
131 |
Initialization (INIT) |
4 (four) |
68 |
132 |
Requested (REQ) |
5 (five) |
69 |
133 |
Activation (ACT) |
6 (six) |
70 |
134 |
Activation confirmation (ACTCON) |
7 (seven) |
71 |
135 |
Deactivation (DEACT) |
8 (eight) |
72 |
136 |
Deactivation confirmation (DEACTCON) |
9 (nine) |
73 |
137 |
Activation finished (ACTTERM) |
10 |
74 |
138 |
Return information caused by a remote command (RETREM) |
11 |
75 |
139 |
Return information caused by a local command (RETLOC) |
12 |
76 |
140 |
File Transfer (FILE) |
13 |
77 |
141 |
Interrogated by a general interrogation (GENINT) |
20 |
84 |
148 |
Interrogated by an interrogation from group 1 to 6 (INRO1 to INRO16) |
21 to 36 |
85 to 100 |
149 to 164 |
Requested by a general counter interrogation (REQCOGEN) |
37 |
101 |
165 |
Requested by an interrogation from group 1 to 4 of counters (REQCO1 to REQCO4) |
38 to 41 |
102 to 105 |
166 to 169 |
Identification type (ASDU) unknown (UNKTYPE) |
44 |
108 |
172 |
Cause of transmission unknown (UNKCOT) |
45 |
109 |
173 |
Common ASDU address unknown (UNKCOMMONADDR) |
46 |
110 |
174 |
Information object address unknown (UNKOBJADDR) |
47 |
111 |
175 |