Counters are not defined by the IEC 60870-5-103 standard in general. A private data unit ASDU 205 is used to define counters. All IEC 60870-5-103 masters does not support this non-standard ASDU type.
Table 1. ASDU 205 Class1 event message outlook
| Octets |
Description |
| 205 |
Type ID |
| 0×81 |
VSQ (= one data) |
| 1 |
COT (= spontaneous) |
| Addr |
Unit address |
| FUN |
Function type |
| INF |
Information number |
| LSB |
Counter value |
| : |
| : |
| MSB |
| [ms] |
Time stamp |
| [min] |
| [hour] |
Table 2. Counter value outlook in detail
| Octet |
Description |
| 1 |
Bits 0...7 = Counter bits 0…7 |
| 2 |
Bits 0…7 = Counter bits 8…15 |
| 3 |
Bits 0…7 = Counter bits 16..23 |
| 4 |
Bits 0…3 = Counter bits 24...27, Bit 4= sign, Bits 5...7 = Not used |
In practice only the energy values from the internal PEMMTR function are pre-mapped into ASDU 205 values.
Table 3. ASDU 205 pre-mapped values
| IEC 61850 object |
Description |
FUN |
INF |
| LD0.PEMMTR1.SupWh.actVal |
Reversed active energy |
133 |
51 |
| LD0.PEMMTR1.SupVArh.actVal |
Reversed reactive energy |
133 |
52 |
| LD0.PEMMTR1.DmdWh.actVal |
Forward active energy |
133 |
53 |
| LD0.PEMMTR1.DmdVArh.actVal |
Forward reactive energy |
133 |
54 |