13 appendix, 1 structure of the system network, 2 principle of the communication network – SMA POWER PLANT CONTROLLER User Manual
Page 57: 3 scaling of the analog measuring channels
SMA Solar Technology AG
13 Appendix
Operating Manual
PPC-BE-P7-en-13
57
13 Appendix
13.1 Structure of the System Network
Two networks can be connected to the Power Plant Controller. This means that the output values can be transmitted to
two PV system networks.
The Power Plant Controller delivers the output values for the Cluster Controllers and the output values for the
Sunny Centrals via separate LAN interfaces.
To ensure the correct transmission of the output values, the following rules must be observed:
• If Sunny Centrals and Cluster Controllers are installed in the system, we recommend that they are organized in
separate networks.
• If the Sunny Centrals and Cluster Controllers have to be operated in the same network, only one network can be
used for transmission of output values. In this case, the time interval for transmitting output values is extended to at
least the time interval determined for the Cluster Controller.
13.2 Principle of the Communication Network
The Power Plant Controller communicates with the connected devices, with the network analyzer, the grid operator, and
the SCADA system via Modbus protocol.
The Modbus protocol is a communication protocol that is based on a client-server architecture.
Figure 16: Principle of the communication network of the PV system with Power Plant Controller (example)
13.3 Scaling of the Analog Measuring Channels
The Power Plant Controller can process both analog and digital measured values.
If a network analyzer is used, the measured values are scaled automatically.
Analog measured values are measured at the point of interconnection and converted by a transducer into values that the
Power Plant Controller can process. Since the transducer can deliver values for active power, reactive power, voltage or
frequency, the input values at the Power Plant Controller must be scaled. This is the only way that the
Power Plant Controller is able to convert into technical values and continue processing the measured values from the
values supplied by the transducer.
For scaling, the possible range of the converted values and the range of the measured values must be entered in the user