By Timothy A. Martin
Recent advances in technology have opened a whole new set of remote monitoring and control opportunities for the water industry. Developments in hardware, communications, and back-end management systems are giving users new visibility into the status of remote processes and equipment. Meanwhile, marketplace forces are driving costs to new lows, allowing users to look at monitoring applications that were previously outside consideration because of cost and justification challenges.
Basic Telemetry
Telemetry is defined as the measurement and control of remote locations and equipment. Every telemetry solution has four essential parts (see Figure 1):
• Sensors, probes, and control devices – These actually measure and control the desired physical phenomenaU tank level, flow rate, temperature, pressure, chemical concentration, pH, etc.
• Data aggregation – This device connects the sensors to the rest of the system. It can be as simple as a sensor transmitter, and as sophisticated as a PLC (programmable logic controller), intelligent RTU (remote terminal unit), or more advanced remote processor.
• Communications – This is how the data gets back and forth from each remote location. Communication methods can include hard-wired, telephone (POTS, or plain old telephone service), radio, cellular, satellite, etc.
• Applications – Human-machine interface (HMI) is how the data is turned into useful (and available) information. This can be a simple readout in a central location, a traditional SCADA (supervisory control and data acquisition) system, or a customized, managed application allowing "anytime, anywhere" access.
How each part fits together with the rest of the solution is critical to operation of the system – a faulty $200 sensor can render a hundred-thousand dollar system useless, likewise an intermittent radio link. Any system is ineffective if the HMI doesn't deliver information in a usable format, wherever and whenever it's needed.
Telemetry Project Justification
Telemetry projects are like anything else an organization does – they have to be justified based on the value they bring, and the difficulty (and cost) of implementation. Every project fits somewhere within a range of value and difficulty (see Figure 2).
A curve divides the chart; projects that fall above the curve get done, and projects below the curve can't be justified. The shape of the curve varies for every organization, and over time within organizations, based on budgets, priorities, and resources. Consider the example of two similar telemetry projects – monitoring equipment in pump stations – one in an easily accessible area, one quite a bit more remote. The value of monitoring those pump stations is the same (all things considered), but the cost of monitoring the more remote station pushes it below the justification curve. For the moment, it's simply too expensive to justify a monitoring project for that pump station.
Next Generation Advancements
Technology advancements are impacting each component of an overall telemetry solution, as well as having a major effect on which side of the justification curve projects fall. Enhanced technology has a two-fold influence on projects. First, improvements in technology capabilities increase the value of a project – more can be done, easier, better and faster. Second, costs are constantly being driven down. The combination of these forces is making more and more projects practical and justifiable (see Figure 3).
Telemetry project value is being driven up and costs driven down at each level of the solution. In several areas advancements have been revolutionary, enabling a whole new generation telemetry solutions that simply weren't practical until now.
New sensors and probes are delivering a wider range of monitoring capabilities. Lower in cost and more easily deployable, the expanding range of industrial sensors available is constantly adding new measurement tools for telemetry projects. Also, more equipment is being "telemetry enabled" with standard interfaces allowing automated control of equipment at a level previously not possible.
Data aggregation devices have seen a more profound impact from technology enhancements. Significantly more processing power is being driven to remote sites in smaller, more reliable, more cost effective packages. These new devices are capable of much more advanced local monitoring and control – far beyond what a simple sensor/PLC implementation can accomplish. Combined with advancements in communications, sophisticated control networks can be deployed quickly and easily. For example, consider a wastewater odor and corrosion control application. Many conditions are constantly changing throughout the treatment system – influent from a wide variety of sources, downstream H2S concentration, pH, weather, etc. New telemetry technology can continually monitor all these changing conditions in real time and can take immediate action to adjust treatment for peak effectiveness – all automatically, across the entire geographically diverse system. Dynamic, automatic control of the entire system adapts to dangerous and destructive odor and corrosion conditions where and when they develop while preventing costly over-treatment.
Going Wireless
Major advancements in communications technology allow these sophisticated yet cost effective telemetry networks to be built. For years, the only feasible way to get a telemetry signal from a remote location was to physically run wire (either dedicated or POTS) to the site or install a dedicated radio network – with the required towers, repeaters, etc. Both methods can be very expensive to install and maintain. Cellular data communications (CDMA 1XRTT, GPRS, EDGE) are becoming an increasingly attractive alternative. As the cellular carriers consolidate their networks and roll out new high-bandwidth data services, coverage, reliability, and throughput have soared. Intense competition for high volume corporate and industrial data customers have driven prices to extremely attractive levels. Further, the carrier is responsible for maintaining the network, offering significant reliability benefits and ongoing cost savings.
Another emerging communications technology that's newly practical for mainstream telemetry projects is satellite data service. Satellite remains one of the more costly communications methods, but newly available hardware and data service opens up many new "extremely remote" applications, where satellite offers the only viable communications coverage. And, also on the horizon for short and medium range telemetry applications are the evolving wireless broadband technologies based on WiFi/802.11 and WiMax/802.16 standards. Telemetry systems taking advantage of any of these enhanced communications technologies literally offer plug-and-play ease of deployment. All these factors again combine to deliver much more value for telemetry projects, much more cost-effectively.
Secure Solutions
Security concerns in our post-9/11 and Sarbanes-Oxley world are also driving the deployment of telemetry solutions to previously unmonitored sites, particularly with wireless communications. Companies recognize their growing security obligation and are looking to the latest in telemetry technology to better secure and control every facet of their operations. Besides the cost and reliability benefits of the latest cellular and satellite data networks, encrypted wireless communications can be significantly less vulnerable to tampering and disablement. Reliability can be enhanced further using multiple communications modes in the same system; for example, having satellite communications on automatic fail-over in the event primary cellular communications are compromised. Higher bandwidth and on-site processing power allow sophisticated security applications including intelligent intrusion and motion detection, video pattern recognition, and automated alert escalation. The lower cost and increased capabilities of next-generation telemetry solutions make all this practical with one system for both operational and security monitoring.
Bringing It Together
New HMI applications tie all the other components of the telemetry solution together, and have become increasingly powerful and accessible. Managed application technology allows operation from any location in the world 24 x 7 x 365 days a year, generally using any internet-connected device and a standard – web browser. Information can be displayed in a wide variety of formats, allowing users to design their own custom information display. They can also interface with existing SCADA systems for easy integration into existing monitoring and control networks. Users also have the ability to download reports of all monitored data for import into spreadsheets, databases, and other applications. Monitored conditions can be tracked and thresholds can be set to issue alarms in the event conditions require attention or manual intervention. Alarms can be delivered to the user's support, maintenance, and management teams via any combination of email, PDA, fax, pager, or telephone. This "anytime, anywhere" capability of new applications increases a telemetry project's value tremendously, bringing the information to the user where it's needed, rather than forcing the user to go to the source of the information. New application development technology can cut customer development and deployment time to a fraction of what it's been in the past – speeding project rollout, cutting costs, and eliminating the risks of a long-term development project.
Conclusion
It's possible to take advantage of these new remote monitoring and control applications easily and quickly, without long capital approval cycles and costly surprises. Lower solution costs translate into instant return and benefit. Because next-generation telemetry solutions are so cost effective and easy to deploy, they make sophisticated management and control practical for equipment and locations that simply weren't possible before. Justification is simple and immediate – saving just one trip per month to a remote site to read a tank level or make a chemical dosing change can pay for an entire solution. Users see immediate savings in manpower, chemical usage, leak detection, and process efficiency, to name just a few of the potential benefits.
About the Author: Timothy A. Martin is manager of telemetry solutions at Altivia Corp., of Houston. Altivia's specialized chemistries, technologies, and services are utilized in municipal and industrial water and wastewater treatment, and environmental remediation, treating 5 billion gallons of water in over 600 U.S. facilities every day. Martin can be contacted at 866-258-4842 or [email protected].
