Controlled environment horticulture has been used in different forms for many years. In fact, residues of greenhouses dating back as early as AD79 have been found in the city of Pompeii.
The modern greenhouses, on the other hand, are believed to originate in the 13th century in Italy. Greenhouses (Figure 1) are used for growing vegetables and flowers in individual gardens and commercial garden centers. Most people will be familiar with irrigation systems that are utilized for supplying water to these greenhouses as well as the use of heaters for controlling the temperature, all of which extend the growing season.
Figure 1. A typical greenhouse
Contemporary systems have been designed for controlled environment horticulture to further improve the growing conditions, with advanced computer-controlled sensors coupled with sophisticated software models that are capable of controlling the temperature, water, light as well as the level of pH, humidity, carbon dioxide and nutrients.
Plants need energy to grow. This energy is acquired from light energy during the photosynthesis process, which changes water and carbon dioxide into oxygen and glucose. In huge glass houses where many number of plants are grown, the atmospheric carbon dioxide can become depleted and this in turn can slow down the photosynthesis process and ultimately lead to carbon dioxide enrichment. Sometimes, systems are provided to artificially improve the carbon dioxide available to the plants.
According to a study conducted by Tremblay and Gosselin in 1998, increasing the level of carbon dioxide in greenhouse settings from 350ppm to 700ppm can increase crop yield by as much as 33%. Therefore, advanced control systems developed for controlled environment horticulture include carbon dioxide sensors, which help in controlling the release of carbon dioxide into the controlled greenhouse environment.
Earlier in 1956, Edinburgh Instruments’ founder published a paper on the design and development of infrared band pass filters, which form a critical component of contemporary IR bench sensors. This technology was commercialized by Edinburgh Sensors over the last four decades, resulting in a reputation for long term stability, precise, reliable and low maintenance gas-sensing solutions. These products are widely used across the globe in carbon dioxide enrichment systems for plant growth.
Edinburgh Sensors’ Gascard NG is an advanced OEM sensing solution (Figure 2) designed for measuring carbon dioxide. It allows ease of integration and is available with a 0-3000ppm range for carbon dioxide. The sensor includes functions such as extensive temperature compensation and on board barometric pressure correction that are essential in greenhouse environments.
Figure 2. Gascard NG OEM gas detector
The Gascard NG sensor comes with different interface options, such as true RS232 communication, analogue 4-20mA/0-20mA/0-5v, and optional on board LANsupport, allowing easy interface to dedicated computer control systems as well as conventional programmable logic controllers. In addition, the board includes a serial interface for interfacing relay alarms. In case a local display is required for specific application, a modern graphical display or a conventional 4 segment LCD can be controlled with the help of the Gascard NG sensor.
OEM Evaluation and Support
Edinburgh Sensors offers an evaluation kit for OEM development. This kit contains a Gascard NG sensor, a relay board and a sophisticated graphical display interface (GUI), enabling easy assessment of the Gascard NG functions.
Besides OEM gas sensors, Edinburgh Sensors has been offering gas monitors, which are built on its proprietary infrared sensor technology, for a number of years. In fact, innumerable gas monitors have been deployed across the globe. As a result, these products are extensively used for monitoring and controlling the carbon dioxide level in greenhouses.
Edinburgh Sensors’ new Guardian NG gas monitor (Figure 3) is being assessed by several customers for use within this market. This wall-mounted sensor comes in a rugged IP54 enclosure with a sample pump and an integral power supply. These features make it possible to collect samples remotely from more than 30m away. The gas monitor can determine 0 to 3000ppm of carbon dioxide.
Figure 3. Guardian NG gas monitor
Other features of the Guardian NG gas monitor include a precise pressure and temperature compensated measurement of the gas concentration through 4-20mA (or 0- 20mA) and RS232 interface, and a GUI with password protection. The GUI not only shows the compensated gas measurement, but also displays control of the gas monitor alarm functions and calibration.
Edinburgh Sensors supplies advanced sensor products that provide fast, precise, reliable and continuous measurements day after day. The company’s engineers provide technical support and one-to-one customer service during the entire assessment and system integration process.
This information has been sourced, reviewed and adapted from materials provided by Edinburgh Sensors.
For more information on this source, please visit Edinburgh Sensors.