Indoor Sensors Sewi Modbus - temperature, humidity and CO2 measurements

The Sewi AQS/TH Modbus and Sewi TH Modbus indoor sensors measure the temperature and humidity indoors and measure the dew point temperature. The Sewi AQS/TH also measures CO2 concentration levels.

The devices are Modbus-Slaves with RS485 interfaces and an RTU protocol. Modbus masters such as the SPS or MC can use the "Function 04h (Read Input Register)" function to evaluate the values of the Sewi Modbus indoor sensors.

Functions of the Sewi TH Modbus indoor sensor:

- Temperature measurement
- Ambient humidity measurement
- Calculation of the defrosting point temperature

Functions of the Sewi AQA/TH Modbus indoor sensor:

- Measurement of the CO2 concentration in the air
- Temperature measurement
- Ambient humidity measurement
- Calculation of the defrost point temperature

Indications for the calculation of the defrosting point:

Sewi Modbus sensors calculate the defrost point temperature of the ambient air.
of the ambient air. This value can be used to control the defrost point. In addition, a second sensor is required to collect the surface temperature data from the wall or pipe. In addition, the freezing point monitoring (temperature comparison) must be carried out in Modbus master mode.

By means of the monitoring, a possible formation of condensation on the surfaces can be foreseen and appropriate measures can be taken in time to prevent it.

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