Installation of temperature and humidity sensors in explosive (Ex) environments
14-04-2021
We installed temperature and humidity sensors in the adhesives and chemicals warehouse.
In operations with an increased concentration of explosive vapours and gases, the measurement of temperature and, where appropriate, relative humidity must be ensured using devices that are specially designed so that there is no risk of explosion during their operation. These devices must not generate high operating temperatures or sparks that could occur in the electrical circuit. Even a small spark could cause ignition and explosion.
In our case, it was a warehouse for adhesives and chemicals. The customer pointed out several non-standard requests.
- Requires temperature and relative humidity measurements.
- The device must be designed for explosive atmospheres (Ex).
- The record of measured values must be transferred to the company's Ethernet network.
Solution:
- For recording temperature and humidity, we used an intrinsically safe sensor manufactured by Comet system s.r.o. T3110Ex with built-in temperature and humidity sensor. The sensor shows the measured values on the display and sends the measured data to the converter using the current output 4 - 20 mA. This sensor is ATEX certified and is therefore suitable for this purpose.
- Through the passage in the wall, the cable was led to the next room, where the wiring box was mounted.
- The output from the sensor passed through the zener barrier MM 7087+, which is suitable for current loops 4 - 20 mAh.
- Subsequently, the P2520 web sensor converts a 4 - 20 mA current loop into an Ethernet network.
- The customer can view the measured data on a computer or other device that is connected to the network. All you need is a web browser or from ModbusTCP, SNMPv1, SOAP, XML.
- The record can be transferred to the Comet Database or its own database using the above communication protocols.
- If Internet access is provided, WebSensors can also transfer data to the Comet Cloud Internet storage.
