Measure Factory Conditions with Turnkey Environmental Wireless Sensors

Every industrial facility, whether it’s a factory or office building, requires networked sensors for monitoring industrial processes as well as current environmental conditions. Atmospheric conditions that need to be monitored can vary and can include simple measurements such as ambient temperature, or more complex conditions such as monitoring for gas or particulate contaminants.

Usually, the atmospheric sensors are part of the equipment being monitored, but often sensors need to be standalone devices that monitor one specific parameter. Common solutions involve building an Industrial Internet of Things (IIoT) node that specifically senses the desired parameter; however, this can be an overly complicated solution. What is needed is a simple turnkey sensing solution that can be quickly configured and installed.

This article discusses IIoT sensing conditions and requirements, and then introduces and shows developers how to use one such turnkey sensor monitoring system from RLE Technologies. The system requires minimal configuration and transmits basic sensor data using a proprietary and secure wireless protocol that does not interfere with the facility’s Wi-Fi network. The article then shows how these remote sensors can easily connect over this secure wireless network to a central sensor manager that collects the sensor data.

Sensing ambient conditions in industrial facilities

In order to optimize and reduce operating costs, industrial facilities are pushing for increased energy efficiency across all operations. This includes not only the efficiency of the machines and equipment used in the facility, but also for the increased efficiency of the working environment including heating, ventilation and air conditioning (HVAC), as well as air flow for the operator’s work environment and air flow around some equipment. This requires the use of sensors to measure these conditions and report back to a host computer.

Facilities managers are also looking to reduce equipment downtime and ensure operator safety. This can require sensing some areas for conditions that can lead to a potential fire hazard. For example, non-plenum areas in a factory or office building that should not allow air to circulate can have air flow sensors installed. In case of a fire, a non-plenum area may be designed to intentionally not allow oxygen to circulate. Unwanted air flow can cause a fire to spread over a greater area, hindering automated fire equipment from extinguishing the flames, or preventing the fire from dying out due to lack of oxygen. In these cases, supplying external power to air flow or temperature sensors may be either impractical or forbidden, requiring battery-powered sensors to be installed.

Also, sometimes a sensor needs to be placed in a remote or hard-to-access location, again requiring the use of battery power for the sensor. One example is a differential pressure sensor for a filter that needs to remove contaminants from an operation; or more common is the sensing of pressure on both sides of a remote HVAC filter.

In all such cases, the goals for designers are extended battery life for the sensing nodes, as well as simple, low-cost deployment.

Wireless ambient sensor networking

One solution is a WiNG wireless environmental sensor network based on a proprietary wireless interface technology from RLE Technologies that operates in the 900 megahertz (MHz) and 868 MHz bands. WiNG devices have a range of up to 100 feet (ft.) through multiple walls or 600 ft. line of sight.

Each sensing node can be easily configured to deliver temperature, pressure, and air flow data. Up to 250 WiNG sensors can be monitored and controlled by the WiNG WiNG-MGR wireless network manager (Figure 1). This simplifies the configuration of the sensor network by not relying on or interfering with the industrial facility’s existing Wi-Fi network. For larger facilities, a range extender extends the range to 1,000 ft. and allows up to 400 sensors to connect to the WiNG-MGR.

Figure 1: The RLE Technologies WiNG wireless network manager can easily connect up to 250 WiNG wireless sensors with a range of 100 to 600 ft. depending on obstacles. Range extenders can expand this to up to 400 sensors as far away as 1000 feet. (Image source: RLE Technologies)

Technicians should test the sensor range with full staff and equipment before committing to a sensor layout to ensure reliable wireless transmission.

The WiNG network manager regularly polls the sensors to collect data and to ensure the sensors are functional and can properly communicate with the network manager. It is designed to function in hostile industrial environments, operating over temperature extremes of 0°C to +60°C and at up to 95% humidity (non-condensing).

Wireless temperature sensing

For wireless temperature readings, RLE Technologies provides the WiNG-T wireless temperature sensor (Figure 2). The temperature sensor and transmitter are housed in one unit for ease of installation. It measures 7.1 centimeters (cm) x 2.8 cm x 2.8 cm and can operate over a wide sensing temperature range of -25°C to +85°C and up to 90% ambient humidity (non-condensing). It is specified to operate for up to five years using a 3.6 volt lithium battery, making it suitable for harsh industrial environments such as near furnaces and engines, with high reliability.

Figure 2: The WiNG-T temperature sensor is only 7.1 cm x 2.8 cm x 2.8 cm and has a sensing temperature range of -25°C to +85°C. It supports mounting using magnets, screws, or zip ties, and can also be mounted on a mini-DIN rail. (Image source: RLE Technologies)

If only sensing at room temperatures, battery life can extend to 12 years, but may be limited by the actual lifespan of the battery. The sensor can fit in most crawl spaces, including the awkward confines of plenum and non-plenum spaces. It can also be conveniently mounted in areas near furnaces, air ducts, and inside HVAC equipment using magnets attached to the back. It also supports screw and mini-DIN rail mounting, as well as zip tie mounting using slots in its housing.

The WiNG-T temperature sensor is polled at random intervals between 10 and 20 seconds. Random polling reduces the chance of network collisions with other WiNG sensors, increasing the reliability of the sensor network.

Wireless airflow sensing

For sensing airflow in difficult to reach places, RLE Technologies provides the WiNG-AIR4 wireless high precision air velocity sensor (Figure 3). It can sense air velocity from 0 to 4 meters per second (m/s) with an accuracy of ±5%.

Figure 3: The RLE Technologies WiNG-AIR4 is a high precision air velocity sensor that can detect air flow velocity from 0 to 4 m/s with an accuracy of ±5%. The air velocity sensor is remotely positioned away from the transmitter by a six-foot cable. (Image source: RLE Technologies)

The WiNG-AIR4 air velocity sensor is different from the temperature sensor in that the air velocity sensor is remotely positioned from the transmitter using a six-foot sensor cable. This allows the small air velocity sensor to be discreetly mounted in the target area, while the transmitter is mounted in a location where it does not impede air flow.

With an operating temperature range of -25°C to +85°C, it is suitable for most heating and air conditioning equipment, not only in the duct work but also inside the equipment.

Like the temperature sensor, it transmits its data to the WiNG network manager at a random polling rate between 10 and 20 seconds to prevent data collisions. With a 3.6 volt lithium battery, the battery life is between four and seven years depending on use and conditions. It can be easily screw mounted or attached using zip ties.

Wireless differential pressure sensing

For differential pressure sensing, RLE Technologies provides the WiNG-DAP differential pressure sensor (Figure 4). It can sense pressure differences from -500 to +500 Pascals (Pa).

Figure 4: The RLE Technologies WiNG-DAP differential pressure sensor can sense pressure differentials from -500 to +500 Pa and includes three feet of flexible polyurethane tubing that extends from the transmitter to the target area to be sensed. (Image source: RLE Technologies)

Like the previous sensors it transmits its data to the WiNG network manager at random intervals between 10 and 20 seconds. The operating temperature range is -25°C to +85°C, with a battery life from five to 12 years using a 3.6 volt lithium battery, depending on use conditions and battery specifications.

The WiNG-DAP differential pressure sensor can be used for measuring pressure on both sides of an air filter, where too great of a pressure differential could indicate a dirty or blocked filter, reducing the efficiency of the system. The sensor is also appropriate for measuring pressure differentials in small airways to monitor and validate air flow exchange.

Conclusion

Sensing ambient conditions in industrial facilities can be critical to ensuring the proper operation of equipment and a safe work environment. As shown, RLE Technologies turnkey sensor monitoring systems allow convenient monitoring of ambient conditions with minimal maintenance, while increasing efficiency and improving safety.