The energy counter values are frozen and propagated as ASDU 205 Class1 events with timestamp-based on a send criteria, that can be freely defined.
Freezing and sending
The EC_FRZ binary inputs can be seen in the I3CLPRT function blocks through the Application Configuration tool in PCM600. When a function block detects a rising edge "1" on the EC_FRZ input, it freezes and latches the defined counter values among the present IED real time. Thereafter ASDU205 counter events are created into Class1 buffer.
Some alternatives for EC_FRZ activation
- A common alternative for the operation is that counters should be frozen and transmitted cyclically, once a minute. This can be achieved in Application Configuration tool by defining a 1 minute timer that creates a pulse to the EC_FRZ input. If required it is possible to define other values for the timer, for example, 10 minutes, 15 minutes, 60 minutes and so on.
- If there are several IEC 60870-5-103 units in the network that should transmit ASDU 205 values, freezing can be done at the same moment. The timer signal in one of the units can be connected to a physical binary output signal and wired to physical binary inputs into the other units. Thereafter, the freezing pulse can be synchronized in all the units.
- Freezing can also be triggered from the IEC 60870-5-103 master unit. The IED contains generic control objects like SPCGAPC that can be written from the master. A generic control object is defined as pulsed type and connected to the EC_FRZ input with Application Configuration tool. If the generic control object in parallel can be connected to a binary output and wired to other units, a broadcast freeze can be achieved.