String Monitoring Box (SMB) is an advanced combiner box that aggregates multiple solar PV string inputs into a single DC output while monitoring real-time performance data.

Technical Specifications

§  DC Input Voltage: 
Commonly rated for 1000V DC or 1500V DC systems.

§  String Inputs: 
Scalable from 8 to 32 strings per unit.

§  Current per String: 
Typically monitored up to 15A, 25A, or 30A depending on the shunt or sensor type.

§  Measurement Accuracy: 
High-precision monitoring often achieves ±0.5% to ±1.0% full-scale accuracy for current and voltage.

§  Power Consumption: 
Low-power design, usually less than 3W to 5W for internal electronics.

§  Enclosure Rating: 
Minimum IP65 or IP66 for outdoor protection against dust and water ingress.

§  Material: 
Often constructed from UV-resistant Polycarbonate, GRP (Glass fiber reinforced polyester), or Powder-coated MS.

§  Operating Temperature: 
Rated for extreme environments, typically -20°C to +70°C.

§  Protective Components: 
Includes gPV fuses (10x38mm or 10x85mm), Type 2 DC Surge Arresters, and a lockable DC load break switch.

Monitoring Features

§  Parameters Tracked: 
Individual string current, busbar voltage, internal cabinet temperature, and the status of fuses, Surge Protection Devices (SPD), and DC isolators.

§  Communication Protocols: 
Standard RS485 Modbus RTU is the industry norm for interfacing with SCADA systems or data loggers.

§  Auxiliary Inputs: 
Optional ports for ambient temperature (PT100/PT1000), irradiation sensors (0-10V/4-20mA), and wind speed sensors.

Standard

§  IEC 61439-1&2

§  IEC 60364-7-712

Brands

§  Novatric 

Common Application

§  Solar Installations | Commercial | Industrial solar Installation | Grid Tied System | Agricultural Solar System