Wireless Helps Municipal and Military Agencies Hang-Up on Hardwire Circuits
Paul Mercier, Manager of Business Development
Phoenix Contact, Inc.

Countless reasons exist for going wireless, recent fires in California have motivated several water utility agencies including Rancho Santa Fe Irrigation District in San Diego County, to move away from using hard-wired or telephone based communication for SCADA and Telemetry applications. Also, the military has been upgrading their infrastructure at bases like Camp Pendleton which is vast and sprawling complexes where maintaining and expanding wired infrastructure is costly and more labor intensive than going with wireless solutions. The purpose of this article is to compare and contrast traditional wired sensor and pump/valve controller applications with wireless alternatives for engineers, operators and maintenance personnel to consider as they face the challenge of migrating from old to new technologies.

Today’s engineers and specialized technicians are not as interested in the technology that makes wireless work, but rather in the proper application and use of radio technologies. In basic terms, “What do I use, where do I use it, and how do I use it?” are right up there in most frequently asked questions alongside “How far will it go?” and “Is it reliable, trustworthy and secure?”

Wireless technology is part of our everyday lives in the home and office. In recent years, this technology has made the logical progression from the home and office into the municipal and military facilities world, onto the treatment plant floor and into the field. It adds convenience, reduces installation time and provides solutions to common problems. Replacing or eliminating cables with wireless technology has many attractive features beyond the obvious installation speed (hours versus days/weeks) and cost savings (labor, permits, material). However, there is still an ongoing debate about the level of trust in using wireless products for a control-based application.

Wireless Reliability
Wireless modems and radio telemetry devices have been used in control systems of mission critical pumps for more than 30 years, yet fear of the unknown remains. There have been thousands of successful wireless SCADA implementations for water/wastewater, gas pipeline and utilities that require data delivered in an acceptable one to two seconds. It is important to note the difference between a deterministic, or time-critical, application and one that requires only high data reliability.

The nature of the RF environment dictates that there is no absolute guarantee that any given piece of data will successfully be transmitted and received over the air. However, a well-designed radio will have built-in error checking and retry capabilities that continue sending a piece of information until it is successfully received. This makes it possible to send important data over a wireless link, as long as the entire system can tolerate some amount of latency or delay.

Wireless Advantages
A wireless hybrid network, or combination of technologies like that used at RSFID can provide technical advantages and cost benefits for pump monitoring and pressure reducing valve control applications. Installing wireless systems to replace both communication and sensor signal cabling can reduce the time it takes to engineer and develop the expansion or construction of a pumping plant. The Witch Creek fire in North County took out phone lines into critical sites in the RFSID system leaving them without communication to check and control when needed most.

“We wanted to go wireless in numerous areas and applications so we would be autonomous from telephone company in case of wildfires and earthquakes,” said Eli Standing Warrior, RSFID Maintenance Supervisor.

Jim Gingrich, Lead Maintenance specialist at the District, stated, “There is a ROI of less than two years as each leased line to remote sites averaged $120 a month. We also saved over $15,000 using wireless over installing a fiber link to provide a LAN bridge of the SCADA HMI from the R.E. Badger Treatment plant to the district maintenance yard three miles away.”

The operators at the yard can now keep tabs on their critical pump stations, improving response times and maintenance efficiencies.
The up-front cost of a wireless system is often immediately lower than cabling and conduit costs, and the savings in labor and permits are enormous. A signal that previously took days to bring online using traditional wiring can now be commissioned within hours. With this time savings and flexibility, maintenance crews can deploy wireless nodes for temporary troubleshooting or adding stranded measurement points and streamlining asset management strategies.

To monitor and control pumps remotely, most companies communicate over fiber, copper or some hard-wired cable. Ideally, important sensors that monitor suction/discharge pressure, tank levels, system pressure, flow rates and temperatures can be tied back to the pump controller via wire. A hard-wired network of pump control panels is also ideal, if it can communicate cost-effectively.
But in a world that isn’t always ideal, wireless can be the next best thing to wire. In fact, many locations have found wireless connections provide a more reliable connection than a wired circuit.

Managing lift stations is one of the biggest problems water utility operators face. Lift stations are built-in remote locations spread out around cities and business areas. A lift station typically includes two pumps that pump sewage into massive underground tanks. Over time, clogging or infiltration can reduce a pump’s efficiency, until eventually the pump stops operating.

When a pump stops, the old-fashioned, flashing light system alarms the site, however, at this point, it might be too late. Diagnosing and repairing the problem might take too long, causing spillage to occur. Often the pumps do not completely fail, rather they lose efficiency. Older systems will allow the anomaly to go unnoticed until a spill is detected by residents or some other means. Spills reported by the public often lead to fines, lawsuits and even criminal charges for the wastewater engineer or superintendent.

Tougher EPA and Clean Water legislation have dramatically increased the need for the monitoring and control of sewage collection systems.
A spill occurs every day somewhere in America. It can cost $50,000 to $100,000, not to mention the seemingly irreparable environmental damage. The cost includes the price of pumping out the lift station, new pumps, rush shipping of parts, area cleanup, overtime and other ancillary charges. Wireless pump control products can prevent a spill altogether, which reduces down times and keeps a “lid” on a problem before it hits the headlines.

For example, Camp Pendleton faced a challenging data communications problem. The base has pumping equipment and wastewater units at approximately 129 unattended locations. It used chart recorders, obsolete RTU’s and a telephone link to a single computer to monitor and control all of these sites. Officials needed better information about the status of the remote facilities to prevent spills and protect the environment.

The base has begun to install a license-free, frequency-hopping spread-spectrum, radio monitoring system. This achieved the desired control and security. The system paid for itself by not only avoiding potential fines, but also by saving thousands of dollars in annual telephone expenses and associated field service trips.

Field instrumentation signals are hard-wired into a localized PLC or I/O system, and then sent to a central monitoring location or dispatcher via a telemetry link. The advent of wireless devices to eliminate the hard-wire to the field transmitters has made it possible to reduce costs even further in development, installation, engineering, mounting, startup and maintenance in this type of application.

Understanding the environment and application of the wireless network plays a crucial part in choosing what wireless technology will perform best. Many technologies, both vendor-specific proprietary and standards-based, have been developed and time-tested over the past decade.
Today, proprietary license-free radio devices are most commonly used in municipal and military wireless installations. The radio technology is unique to the device manufacturer and will not operate with another manufacturer’s devices, adding an element of security. Proprietary radios can be customized to fit a specific application, ranging from Ethernet connectivity down to sensor signals, making them suitable for both in-plant and remote site applications. These devices are often much more efficient at transferring data, as the radio platform is optimized for the types and quantities of data that it will transmit. The device can be adjusted to the maximum levels allowed by the local governing body (FCC, IC, etc.,), so longer range RF links can be achieved.

Licensed radios are proprietary systems that require a frequency license from the local regulatory body to operate on a single fixed frequency. The agency issues these licenses to mitigate interference. Licensed radios are considered high power, typically up to 5 watts. This power translates to a long transmission range, often up to 40 miles, that can be required in large facilities like Camp Pendleton which includes 125,000 acres of hilly terrain.

GSM/GPRS is commonly known as cell phone technology. It transmits process data via the cellular network infrastructure. A GSM/GPRS device works like a cell phone, requiring a SIM card and consequently, a monthly billing plan. With this technology, pump management systems can maintain communications even with locations on the opposite side of the globe.

Securing the Network
Despite the increasing acceptance of wireless technology, security is still a primary concern. While data encryption is often the top security concern, there are other security facets to consider.

Physical security is also important to prevent damage to antenna systems and radio equipment. A radio network is only as strong as its weakest RF link. RF security is possibly the most important, and most frequently overlooked, aspect of security. A well-designed wireless network will pay close attention to the types of antennas that are used and where they are mounted.

Implementing a Wireless System
The use of wireless technology in municipal, military and industrial applications will proliferate over the next five years, as will the variety of devices and technologies. There is not a “one-size-fits-all” wireless technology available. A variety of radio platforms exist for specific applications.

A careful analysis of the operational and maintenance requirements is very important before implementing any wireless project. A detailed feasibility analysis of the environment, application needs, security concerns and possible technologies will save the time, dollars and headaches later during the design and implementation of the project.

Paul Mercier is a manager of business development for Phoenix Contact, Inc. with a focus on wireless (Bluetooth, HART, WLAN, Cellular and 900 MHz proprietary) technologies. He has over 25 years experience in instrumentations and controls, spending the past 17 years with an emphasis on developing and applying wireless products and networks for mission critical applications. For more informaiton visit www.phoenixcontact.com.

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