• Gantner Data Logger Q.reader central

Q.reader central / Power Plant Controller PPC

Effective PV Monitoring requires constant, solid and traceable PV Plant monitoring data in order to determine actual performance and fulfil owner/investor expectations. Operators are interested to identify errors and losses in a reliable way to trigger appropriate actions for maximizing energy harvest during the total system lifetime.

The “Q.reader” is a data logger which can make the logging and control of all required PV plant information:

String level (current, voltage), inverter data, meteorological data from weather stations, grid measurements and other state variables (switch gear, transformer status). At the same time, it also acts as the power controller for the grid operator.

This accurate data acquisition and control concept is inverter independent and gives feedback about losses due to inverter malfunction, soiling, shading, PV Module degradation etc. .

The Linux based platform can control up to 100MW plants with just one controller and fulfils all international requirements as the IEC 60870 (communication protocol for supervisory control and data acquisition) for reactive power, ramp rates, etc. or Germany’s BDEW (“Erzeugungsanlagen im Mittelspannungsnetz”). Data collection can be down to one second or more, which is often required by utilities to zoom for grid impacts tests.

Signal conditioning, data storage and transfer, compressing, and communication in many ways are the strengths of this flexible data solution. For communication industry standard Modbus protocols for easy and fast integration is used which enables reliable data exchange within the network. For longer communication distances fiber optic technology is used.

Data transfer is possible by cable (Ethernet/ LAN) or wireless (GPRS/3G or 4G, WiFi) – the loggers meet all standard security requirements (SSL) with lowest power consumption.

The data acquisition system grows with the requirements and distributed Q.series measurement modules can be integrated at any time.

Q.reader- Power Plant Controller PPC Features


       Absolute production constraint
Absolute production constraint is a controlling function which serves to limit the amount of active power generated by the plant at the point of connection

       Power gradient constrain
To prevent disturbances on the network, the power gradient constraint enforces a gradient at which the plant must ramp its active power to the desired set point.

       Voltage Control
The voltage control function is mutually exclusive with reactive power control and power factor control and serves to regulate the voltage at the point of connection.

       Reactive Power Control
Reactive power control is mutually exclusive with voltage control and power factor control and serves to regulate the reactive power at the point of connection

       Power Factor Control
Power factor control is mutually exclusive with reactive power control and voltage control serving to regulate the plant at a constant power factor at the point of connection

       Frequency Control
Frequency control as defined in the grid code considers both under frequency and over frequency conditions

Key features

Power Up to 100 MW of logging and control per device
Control According to world wide grid codes
Analog and digital inputs and outputs via I/O modules z.bloxx or Q.bloxx up to 24 bit resolution, sample rate 0.1 s up to 24 h
 4 x RS485 fieldbus interface Up to 115.2 kbps
Ethernet interface for configuration and data transfer TCP/IP, UDP, FTP server and FTP client functionality configurable functions
Grid interaction based on IEC 60870, DNP 3, Modbus RTU/TCP
Connectivity Protocols from all leading inverter manufacturers are integrated I/O devices (e.g. weather stations, medium voltage parameters)
Data memory with individual logging interval 8GB flash, 0.1 s up to 24 h, individual per channel
Configurable monitoring With auto-alarming via e-mail or SMS, local arithmetic functions
Data access Direct link to the gantner.webportal for worldwide data access
Operating system Linux

Functional Scheme


Data logging and control
Logging interval 8GB industrial flash
Data memory 8GB industrial flash
Grid control, interaction IEC60870, DNP 3, others
Operating system Linux
Communication Interface
RS485 4
Ethernet TCP/IP 2
Protocols Modbus-RTU, Modbus TCP, inverter protocols
Number of devices on the bus Max. 250
Data transfer FTP server and FTP client functionality
Data format Selectable (e.g. csv, json)
SCADA Integration Via OPC-Server
Connection 0.25 mm2 - 1.5 mm2 push-in spring-cage connection
Power supply
Power supply 10 up to 30 VDC, overvoltage and overload protection
Power consumption approx. 6 W
Operating temperature -10 °C up to +55 °C
Storage temperature -40 °C up to +85 °C
Relative humidity 5 % up to 95 % at 50 °C, non-condensing
Case Aluminum
Dimensions (L x H x D) (69.1 x 169.5 x 127) mm
Weight approx. 1700 g
Mounting DIN rail mounting (EN 50022)