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 interface (see Section 7.9 "Selecting the Signal Source and Adjusting the Scaling of Measured Values", page 34).
The range between x0 and x1 refers to the converted values. This range is dependent on the measurement signal used and on the analog input to which the converted values are supplied.
The range between y0 and y1 is the range into which the Power Plant Controller scales the converted values. This is equivalent to the measurement range.
Within the measurement range is the range in which the valid measured values occur. The lower valid measured value corresponds to yMin, the upper valid measured value corresponds to yMax
Measurement signal Analog input Measurement range of
the analog signals Range of the converted values
Standard signal voltage Onboard ‒10 V
10 V x0 = ‒8,192
x1 = 8,192
Standard signal voltage Onboard 0 V
10 V x0 = 0
x1 = 8,192
Standard signal current Onboard 0 mA
20 mA x0 = 0
x1 = 7,367 Standard signal voltage Bus coupler ‒10 V
10 V x0 = ‒32,768
x1 = 32,767 Standard signal voltage Bus coupler 0 V
10 V x0 = 0
x1 = 32,767 Standard signal current Bus coupler 4 mA
20 mA x0 = 0
x1 = 32,767
Example: Scaling of analog input values
Analog voltage signals in the range from ‒10 V to +10 V are received at the analog input. The analog-to-digital converter of the Power Plant Controller uses this to generate a digital signal in the range of ‒8.192 to +8.192. The measured value processing in the Power Plant Controller calculates the reactive power value from this signal, and then limits it to the permitted range from ‒15 MVAr to +15 MVAr.
Lower value for the range of valid measured values:
yMin = ‒20 MVAr
Upper value for the range of valid measured values:
yMax = +20 MVAr Lower signal value supplied by the transducer:
x0 = 8.192
Upper signal value supplied by the transducer:
x1 = 8.192 Lower value of the measurement range:
y0 = ‒15 MVAr
Upper value of the measurement range:
y1 = +15 MVAr
SMA Solar Technology AG 13 Appendix
13.4 Output Value Specification Under Fault Conditions
If transmission of the setpoints under fault conditions is not possible via Modbus protocol, the Power Plant Controller uses a substitution value or the last transmitted value. This is set for each specific system by SMA Service.
Basically, three communication errors are possible:
Once the error in transmitting the setpoints of the Power Plant Controller via Modbus protocol has been eliminated, transmission of the output values calculated by the Power Plant Controller to the devices of the PV system automatically recommences.
13.5 Directive for Secure Passwords
To protect the Power Plant Controller from unauthorized access, you must select a secure password.
SMA Solar Technology AG recommends choosing the password in accordance with the following directives:
• The password has at least five characters.
• The password consists of letters, at least one number, and at least one special character.
• The password does not contain umlauts.
13.6 Type Label
The type label clearly identifies the product. There are two type labels attached to the Power Plant Controller. The type labels are located on the right-hand inside panel and on the right-hand outside panel of the Power Plant Controller.
You will find the following information on the type label:
• Device type
• Option code
• Serial number
• Production version
• Device-specific characteristics
You will require the information on the type label to use the product safely and when seeking customer support from the SMA Service Line.
The output values are calculated with the last valid setpoint or with a substitution value.
Parameterization is carried out at the Power Plant Controller.
Actual values from the network analyzer are not received by the Power Plant Controller.
New output values cannot be calculated. The controller switches to manual operation and transmits the last valid output value or a substitution value.
Parameterization is carried out at the Power Plant Controller.
Output value transmission to the
devices is disturbed Depending on the parameterization, the connected devices work with the last valid output values received or with a substitution value.
Parameterization is carried out at the connected devices.
Symbols on the Type Label
Symbol Explanation
CE marking
The product complies with the requirements of the applicable EU directives.
Degree of protection
The product is protected against interior dust deposits and splashing water from all angles.
WEEE designation
Do not dispose of the product together with the household waste but in accordance with the locally applicable disposal regulations for electronic waste.