Openable multichannel device for external environment, suitable for string-current measurement in photovoltaic plants

Actually, all the solutions in commerce are open-modules or devices with a low humidity protection degree, which were projected for working within closed and waterproof electrical boards. In addition they occupy considerable space: their large dimensions don’t make possible an installation into electrical boards pre-existent. With the actual devices it’s almost impossible monitoring an existing plant without replacing the parallel electrical boards for the existing strings. In many cases, the large volume of the new boards may make impossible the installation.

Easy 4 Hall offers the following advantages:

• • Inconsistent impact plant
  • Essential for the re-certification of the existing parallel boards
  • Easy to install
  • Small size
  • Isn’t necessary to stop the plant when inserting the module
  • It’s possible to get an accurate and reliable data-reading without stopping or disconnecting any string or tighten the
    clamps
  • Each module can monitor up to 8 strings
  • Integrated Modbus communication module
  • The lack of physical connections and terminals on strings eliminate any needs for preventive maintenance
  • It can be used externally without the integration of other waterproof cases
  • No electrical contacts with existing circuits, maximum electrical security and low electromagnetic susceptibility
  • The most simple and economic solution on the Market
  • Patent application registered

The device is made of two rectangular “half-shells”; in the first half-shell ( bottom ) some comb-shaped grooves were made and, by means of them, it’s possible to insert and keep the pose of the cables carrying the currents to be measured. In addition, in this shell are hosted half of magnetic circuits of the sensors, made of ferrite elements, supported and guided so as be coupled very accurately to the remaining part of magnetic circuits (with a controlled pressure force), located in the second shell. This second shell is divided into two compartments: the first of them contains some magnetic elements having a thin air-gap and, within it, there’s a magnetic field sensor for measuring the flux induced by the conductor under test and directed by the magnetic circuit.

In order to get the requested degree of impermeability, magnetic and electronic circuits in the first compartment of the shell are embedded in epoxy resin, instead the accessible side for sensor connection and data output is protected by trimming and by an appropriate mechanical design of the case.

• • It can measure up to 8 string current, without cutting off the connection
  • Current reading by means of Hall effect sensors and a 14 bit analogic/digital converter
  • Internal temperature measurement (Celsius degrees), from -30°C to +80°C, accuracy 1°C
  • 16 bit micro-controller technology
  • Power supply: 12/24 Vdc, 500 mA max
  • The data concerning Temperature and Current values are sent through RTU Modbus on insulated RS-485 serial port
    (possibility of internal termination with jumper)
  • It’s possible to select the readings carried out and the parameters of Modbus protocol (baudrate, parity, address, stop-bit)
  • It’s possible to enter “Config mode” by laying on the case a magnet (supplied), for a time of 5 seconds. This modality is accompanied by an acoustic signal. Modbus parameters can be selected by writing into special registers
  • The case “custom”, printed in plastic material, the double cable-gland PG9, passivation with insulating resin and the O-ring on the lock, make possible the IP65 certification of the device
  • Read current range: ± 10A ; Minimum accuracy: 100 mA
  • External dimensions (without cable gland): 244x64x37 mm