subject: Choosing a Remote Monitoring System for your Greenhouse [print this page] Choosing a Remote Monitoring System for your Greenhouse
The controlled environment of a greenhouse extends the growing season of vegetables, flowers and trees and allows plants to thrive in unusual places. Poinsettias can bloom in Maine in time for Christmas and Southeast Asian bamboo can be cultivated in Georgia. Maintaining the right balance of temperature, humidity, light and soil moisture is critical to optimizing growing conditions in a greenhouse, and so is being notified if levels deviate or something goes awry. This article advises greenhouse growers on how to choose a remote monitoring system that can track important conditions in their greenhouse; allow users to call in at any time for voice status reports; and also send out timely alerts if there are extreme fluctuations, equipment failures, or power outages.
There are a variety of remote monitoring devices on the market with a range of capabilities, including many good options that can be installed yourself. Selecting the right system for your greenhouse depends upon these key factors:
The communications capabilities at your site
The form of alarm delivery you prefer (phone call, text or email)
Your notification contact list (how many people, phone numbers or computers to be contacted)
The number of conditions you want to monitor
The number conditions you want to control
Need for wireless or hardwired sensors
Your budget
Communications Methods
Selecting the right remote monitoring system starts with examining how your greenhouse is wired or situated for communications. A monitoring system will use one or more of these communication methods:
1) Landline telephone
2) High-speed Internet
3) Cellular telephone
4) Satellite
Basic remote monitoring systems communicate via a conventional landline phone connection. These systems are generally the least expensive and many growers find them perfectly adequate for their needs.
If you want a remote monitoring system that can communicate with a PC and is capable of sending out email or text message alerts, you need a web-based device. Note that these systems require installation of a high-speed Internet connection in the greenhouse.
Many greenhouses are built in remote locations where landline phone service and high-speed Internet are not available. Here a fixed wireless terminal (or "cellular terminal") can be added to provide a dial tone for a phone-enabled remote monitoring system. Or, you can purchase an all-in-one remote monitoring system that has the cellular communications capability built in. Note that for either option, you'll need to make sure that there is reliable, consistent cell phone service at your location and that the unit is compatible with the transmission bandwidth used by your cellular carrier.
In extremely remote locations without landline, Internet or cellular service, a satellite-based remote monitoring system can be used. These sophisticated systems are fully-featured and provide 100% coverage "anywhere you can see the sky" throughout the U.S. as well as in many other countries. Not surprisingly, satellite-based systems are also the most expensive.
Alarm Delivery Options
If the temperature in your greenhouse were to suddenly drop below freezing and your entire inventory of ornamental plants were at risk, how would you like to alerted? Depending upon the type of remote monitoring system you choose, you can be notified by phone call, text message to your cell phone, alpha-numeric message to your pager, fax, or email to your computer or smart phone. Most systems can send out a voice alert to multiple phone numbers and some systems even allow you to record your own custom voice message. However, only Internet-based systems communicate via text messaging or email. Unexpected events can happen at anytime and have dire consequences, so it is important to pick the type of alarm alert that you and your staff are most likely to receive and respond to, 24/7.
Notification Contact List
Remote monitoring systems are persistent. Equipped with an autodialer, they will send out alarm notifications to your programmed list of contacts until acknowledged and proper action is taken. Standard remote monitoring systems can be programmed with four or eight landline or cell phone numbers. More advanced systems will call as many as 64 phone numbers. Web-based models send out text messages or emails to a distribution list you create. In selecting the right model, consider how many people, phone numbers, or PCs you want your remote system monitoring system to notify when there is an emergency.
Conditions to Monitor
Controlling growing conditions in a greenhouse is essential to a successful harvest. Temperature, relative humidity, CO2 levels and power status are some of the key variables that greenhouse growers need to continuously track and adjust. The most basic remote monitoring systems for greenhouse applications will monitor temperature and three other conditions. More advanced systems typically have inputs for up to eight sensors to detect smoke, zone water presence, motion and soil moisture, for example. Some high-end systems can be expanded to accept additional inputs.
Growers who want to track and view the history of growing conditions in their greenhouse can choose one of the more sophisticated remote monitoring systems with data logging capabilities. These systems store stamped records internally and allow either local or remote retrieval of the data, which can then be analyzed and graphed for a detailed view of the trends at the greenhouse site.
Create a list of conditions you want to monitor and choose a system that has an adequate number of sensor inputs. If having access to historical data is important to your greenhouse operation, consider investing in a higher-end system that offers data logging.
Conditions to Control
In addition to monitoring critical growing conditions, the majority of remote monitoring systems also feature one or more relay outputs that allow you to switch an external device, either automatically when an alarm occurs or manually via telephone or computer, depending upon the model. Adjusting the temperature remotely by phone is one popular use of this function. Some high-end systems are expandable, allowing you to increase the number of output relays so you can control additional devices at the site, such as turning on fans to cool down the greenhouse if the internal temperature gets too high.
Wireless or Hardwired Sensors
Basic remote monitoring systems will accept four or eight hardwired sensors. However, if you need to monitor critical remote locations such as multiple greenhouses, barns, garages, or any installation where running a long wire is not practical or convenient, choose one of the more advanced systems that also accept wireless sensors. Wireless sensors typically operate up to 300 feet (line-of-sight) away from the monitor, but that distance can be extended up to 4,000 feet (line-of-sight) by adding wireless repeaters.
Cost
The cost of a remote monitoring system relates directly to its features and capabilities, with landline telephone-enabled systems at the low end and satellite-based systems at the high end. List prices generally range from $400 to $2,500. Sensors are purchased as individual accessories. Many systems can be installed yourself and come with the additional benefit of no monthly service charge, a big savings over using a professional security company.
Summary
With the wide range of remote monitoring systems available today, you should be able to find a system that meets your criteria and fits your budget. Use this checklist in this article to guide your decision making process, beginning with the communications options at the site of your greenhouse. A thoughtful survey of the greenhouse conditions you want to monitor combined with developing a practical notification contact list will help you narrow down your choices. For additional technical and purchasing information on remote monitoring systems, go to: www.diycontrols.com.
