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The MODBUS 485 RTU converter called "M-Box" is a digital signal conditioner to convert the Voltage output of a solar radiation sensor, PT-100 or 10kΩ NTC temperature sensor into a MODBUS 485 RTU output. The converter can be used with all passive EKO radiometers or any other mV sensor to be connected to data loggers or inverters with a MODBUS 485 RTU input channel. By using the signal conditioner the sensor cable can be easily extended over long distances without any signal loss or potential electromagnetic interference in noisy industrial environments. With MODBUS up to 100 different sensors and converter units can be addressed and connected in parallel.

The mV signal of the solar sensor will be converted to irradiance 0 - 1600 W/m2. In this case the sensitivity factor of the solar sensor will be set to the converter. With the optional USB controller and EKO Sense software (Multiple languages) the converter settings can be freely changed. This tool will be needed in case the sensor sensitivity might need to be changed after a periodical solar sensor re-calibration.

For practical installation, the converter is placed in an IP65 Aluminium box with universal cable glands. It has robust input/output screw terminals, which can be easily connected to the signal cable that leads to the measurements system at the installation site. EKO can pre-connect the solar sensor cable to simplify your process.


  • Universal MODBUS 485 RTU Converter
  • For Solar Sensors, PT-100, NTC 10kΩ
  • Up to 100 units in parrallel
  • Easy menu settings
  • Advanced sensor temperature correction and linearity functions
  • IP65 All weather enclosure
  • Optional USB contoller and EKO sense control software to change settings
Signal Converters


Characteristics Details
Input Range 1 DC 0 to 100mV
Input Range 2 PT-100 (2W / 3W* / 4W*) / NTC 10kΩ
Output Digital (Modbus 485 RTU)
Outpt parameters W/m2 / Temperature (°C, K, F) / Sensor parameters
Resolution <5μV / <0.1°C
Input Impedance >10MΩ
Temperature Response (-20 to 50°C) < 0.2%
Response Time < 1s
Non-Linearity < 0.1%
Zero Offset <5μV
Operating temperature range -40 to 80°C
Power Supply DC 12~24 V ±20%
Power Consumption <0.3W
Dimension φ45 × 27.1mm
Weight 0.03kg

* 3W / 4W PT-100, combined inpt terminals 1 and 2.

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