• string.bloxx 116 (16 channels)


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.
With the monitoring of PV Module strings, design and production errors will be recognized on the DC side with high resolution down to PV Module level.

Using DC shunts (vs. Hall Effect sensors) the string.bloxx provides current measurements typically 10 times more accurate and not susceptible to temperature variance. This equates to higher accuracy measurements and better understanding of true system performance. In addition, string voltage (up to 1000V) and DC power on every string can be continuously monitored ensuring maximum system productivity.

Continuous measurement of both cabinet and panel temperatures, along with overvoltage monitoring and main switch control greatly and improves system diagnostics.

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

The string.bloxx communication uses industry standard Modbus protocols for easy and fast integration and reliable data exchange with the data logger. For longer communication distances fiber optic technology is used.

Key features

Connection for strings Up to 32 PV strings
Analog input for current measurements 16 channels
String current ± 26 A string current (calibrated), ± 416 A summary @60°C
Analog input channel for voltage measurement 1 channel, 0-1000 VDC string voltage
Input channels for temperature 2 channels, panel and switch cabinet temperature
Digital inputs 3 inputs, monitoring of overvoltage protection and main switch
Integrated LC display Display of all readings, configuration
Mounting DIN rail or wall mounting according to DIN 50022
Digital output 1 output, actuation of main switch
Signal conditioning Calculated DC Power, linearization, mean value, scaling, alarm
RS485 fieldbus interface Up to 115.2 kbps: Modbus-RTU, ASCII (optional OEM protocols)
Connectivity Data logger (e. g. Q.reader) and gantner.webportal for worldwide access or other 3rd party applications
Electromagnetic Compatibility According to EN 61000-4 and EN 55011
Power Supply 10 up to 55 VDC

Functional Scheme


Input Current
Max. Number 16
Range ± 26 A
Accuracy 0.25 %
Connection 0.25 mm2 - 6 mm2 push-in spring-cage connection
Current measurement
Max. 416 A
Connection M8 bolt connector for cable ring terminals
Voltage measurement
Number 1
Range 0-1000 VDC
Accuracy 0,2 %
Connection 0.25 mm2 - 6 mm2 push-in spring-cage connection
Input Temperature
Number 2
Type Pt1000, 2- and 4-wire
Range -40 till +160°C
Accuracy 0.5 %
Connection 0.25 mm2 - 1.5 mm2 push-in spring-cage connection
Digital Inputs
Number 3
Input State
Connection 0.25 mm2 - 1.5 mm2 push-in spring-cage connection
Digital Output
Number 1
Output State, alarm
Contact Relay change
Load 30 VDC/1000 mA (ohmic load)
Connection 0.25 mm2 - 1.5 mm2 push-in spring-cage connection
Power Supply
Power supply 10 up to 55 VDC, overvoltage and overload protection
Power consumption approx. 1.5 W (0.4W at 30 seconds sample rate)
Connection 0.25 mm2 - 1.5 mm2 push-in spring-cage connection
Communication Interface
Standard RS-485, 2-wire
Data format 8n1
Protocols Modbus-RTU, ASCII: 19.200 bps up to 115.200 bps
Number of devices on the bus max. 250
Connection 0.25 mm2 - 1.5 mm2 push-in spring-cage connection
Operating temperature -20°C up to +60°C @ max 384 A current
Operating temperature -20°C up to +75°C @ max 192 A current
Storage temperature -40°C up to +85°C
Relative humidity 5 % up to 95 % at 50°C, non-condensing
Case Polycarbonate
Dimensions (W x H x D) (305 x 128 x 55) mm
Weight approx. 600 g
Mounting DIN EN-rail or wall mounting