How to perform wireless temperature monitoring on 1000 nodes?

We have introduced the scheme of data acquisition and recorder to collect and read data remotely. This article mainly introduces the scheme of wireless temperature measurement in a wide range and multiple nodes.
This solution uses a wireless module + temperature measurement module layout, which can read temperature data in a wide range through multiple nodes.


Then why choose such a scheme?
First of all, the wireless module, take the selected LM400T as an example. LM400T is an industrial-grade LoRa networking transparent transmission module. At present, the characteristic of LoRa is that it can transmit over long distances to meet the needs of a large application range. The industrial field environment is generally harsh. In the case of large-scale data transmission, LM400T has strong anti-interference ability, low power consumption, and requires maintenance. The cost is less.


       The LoRa networking transparent transmission module is embedded with an ad hoc network transparent transmission protocol, which supports users' one-click ad hoc networking. For conventional industrial sites, the area covered by the test points is generally larger, and more test nodes are needed. Using the self-organizing network function will avoid tedious operations on configuration. In the ad hoc network mode of the module, the master module will automatically select the unused physical channels and modulation parameters around to form an independent network, and can automatically assign a local network address to the slave module. The slave module is using After enabling the self-organizing network function, there is no need to perform any configuration operations, and the slave module can communicate with the host after joining the network.


Figure 3 Ad Hoc Network Topology
LM400T provides dedicated meter reading protocol, CLAA protocol and LoRaWAN protocol, users can directly develop applications without spending a lot of time on the protocol. LM400T supports secondary development, built-in MCU, and can develop application layer through interface functions, such as temperature data collection.
Where does the temperature data collected by LM400T come from?
TPS02R, is a small module that integrates MCU and ADC acquisition circuits. Compared with the data acquisition recorder we have introduced before, which has rich collection, operation and storage functions, this module may seem ‘thin’. However, the module adopts an ultra-small volume design, which is easier to integrate into the temperature measurement system. In industrial sites, large-scale placement of acquisition equipment or miniature acquisition systems, volume and power consumption are issues that have to be considered.


It can support 2 thermal resistance sensors, and the measurement accuracy is as high as ±0.2℃. For some industries, TPS02R has a built-in 2500V electrical isolation circuit, which can effectively suppress the ground loop interference during temperature measurement.
Of course, what the front end of this solution needs is a thermal resistance sensor. For temperature testing, thermal resistance and thermocouple are very familiar accessories, and there are different models to choose from in different test environments.


The above is a brief introduction to the current large-scale multi-node wireless temperature measurement. In general, it is to use the function of supporting secondary development of the LM400T in the LoRa module, with a smaller temperature acquisition module, supplemented by peripheral circuits, and the thermal resistance The temperature is collected and then sent wirelessly.