Measuring temperature 29.02.2020 08:46 29.02.2020 08:46

The interior temperature is usually measured by a temperature sensor mounted on the wall of the room.

The highest quality of the measurements is achieved if you comply with several principles:

 

Placement of the temperature sensor

Temperature sensor should be mounted about 130 ÷ 150 cm high, always on the wall, which is not affected by other sources of heat or cold.

It is not desirable:

  • to put the sensor on an external wall with no thermal insulation
  • to put the sensor too close to the door and other places with variable draft
  • to put it close to air-conditioning vents
  • to put it above the sources of heat (the fridge, TV, a light source)
  • to install it in a place where cold air flows - openings in the ceiling, draft to put it in unsealed pipes with cables to the sensors, etc.,
  • to locate it in the corner or some other place with limited natural air circulation of the air in the room.

 

In large rooms it is not recommended to locate the sensors too far from the "point" sources of heat (panel radiators, etc.), because even though the temperature will be regulated accurately at the location of the sensor, it can fluctuate by several degrees Centigrade near the heat source. Then the temperature fluctuation depends on typical places where the residents spend most time and on its distance from the heat sources and from the sensors. .

 

Selecting the sensor.

The spatial room temperature can be measured in several ways. It depends on the requirement of the design of the measuring element itself, on the fact if you simultaneously measure the floor temperature, whether you prefer the bus elements distributed around the house (CFox, RFox) or direct temperature sensors connected with cables to the analogue input of modules in the control panel. The spatial temperature is measured simultaneously by the heating controllers and temperature sensors, which can be connected to the CFox wall-mounted controllers (“switches”).

 

Measurement accuracy.

The sensors measuring the interior temperature usually achieve a resolution of 0.1 to 0.3 °C, the measurement accuracy (excluding the sensor location) is about ± 0.3 ÷ 0.6 °C; some sensors (e.g. the NTC) measure with a larger absolute error, which could be corrected by a programme (offset of the measured temperature in the module configuration, etc. ).

Due to the potential effect of the sensor placement (which cannot always be influenced) on its accuracy, it is appropriate in some cases to add a service temperature correction, which should be done after the system has been installed and all temperatures stabilized with the help of an external thermometer. Some combined modules (a backlit display with a temperature sensor, etc.) also influence the measured temperature to a certain extent due to their own electronics heat dissipation. Therefore, the system should be stabilized before reprogramming the measured temperature.

The temperature measurement and control of its accuracy must always be done when the system is stabilized - after being turned on, the heating must function for at least one hour; the room must be in a stabilized state (warm, with minimum movement of people). A greater movement of people has a significant impact on the temperature and the relative humidity changes in the room; this should be taken into account when conducting an inspection of the accuracy or a software compensation of the sensor.