Industry News Display
2011-02-28 Control Engineering
Tips & Tricks: Wireless technologies can improve supervisory control and data acquisition applications. Match technologies to your needs, reduce costs, consider a hybrid approach, and heed six more pieces of advice. See graphic, table.
By: Dan Steele, FreeWave Technologies Inc.
Industrial communications radios connected to I/O modules for supervisory control and data acquisition (SCADA) applications have become faster and smarter and their firmware easier to upgrade. More options and frequencies include 2.4 GHz for short range I/O and 900MHz for long range or for networks that have just a few sites requiring I/O connections, according to Dan Steele, FreeWave Technologies business development executive. Steele spoke at the 30th annual Colorado Rural Water Association Conference on Feb. 16, and he subsequently shared nine tips with CFE Media to improve SCADA-based network communications.
1) Assess technology options for the SCADA network, identifying needs, goals, and limitations. When it’s time to research technology options, observe what’s available today and what’s going to be available in the future, heeding the “buyer beware” saying. Communication products vary in many ways, and each manufacturer and/or technology has advantages and disadvantages. No single product—and likely not a single manufacturer—can meet all application needs.
2) Reduce costs. While some companies seek to continue to preserve existing investments of wired and wireless technologies, wireless options have clear advantages for SCADA systems. Most obviously wireless installations reduce labor and material costs by avoiding hardwiring remote assets. Speed of deployment adds savings. Wired systems can take days or weeks to be properly installed. Wireless networks generally require only the end points to be installed, saving substantial time and costs. Networks need to scale gracefully as the number of end points increases. After installation savings, scalability is the biggest advantage of wireless over hardwiring, including slow integration into wired systems as it’s implemented.
3) Consider hybrid benefits, tossing out old perceptions. If you need mobile SCADA network access, find somebody that offers it. If you have a microwave tower place, use it. Piggyback slower licensed radio networks with faster 902-928 MHz frequency hopping, AES encrypted networks. Know that you can install IO capable radios (analog and digital signal, 4 to 20 and 1 to 5) to relay contact closures or other data without adding a new PLC or RTU.
4) Maximize SCADA system value. With telemetry technologies, such as spread spectrum radio, the same radio used in remote telemetry units (RTUs) can act as a slave sending data back to the SCADA host, and as a repeater to other field devices or other RTUs. This allows almost limitless network expansion by using remote sites as a series of repeaters, and by using radios in the RTUs to poll the instrumentation. Polling the instrumentation creates a second network reporting wirelessly back to the RTU. This short-haul network is the equivalent of a local area network (LAN).
5) Don’t use a proprietary SCADA system. By using a nonproprietary SCADA system, users gain real-time access, control, and monitoring of their network (including all the devices and functions of their network). They can manage requirements of an ever-growing system allowing them to manage their network in real time with fewer bodies and hours invested. Security and safety improves with better monitoring. For instance, some industrial systems don’t contain a process for monitoring the cathodic integrity for corrosion (like in water/wastewater and oil and gas) to avoid disaster. But with deployment of a wireless system, they can. They can begin by monitoring simple things, such as pump stations at wells, using I/O radios communicating back to the central SCADA system to get up-to-date information on the tanks’ or pipelines’ status. End users can more quickly resolve an emergency wirelessly, instead of manually.
6) Seek SCADA system flexibility. Advanced flexibility of radio communications offers benefits to new SCADA system deployments and upgrades performance of existing SCADA systems. For example, in water/wastewater industrial applications, there need to be generation/distribution, lift stations, system monitoring, and treatment facility systems in place (or planned) to meet the expanding growth of a community’s population and/or service areas to meet future requirements. Each year, many industries deploy more spread spectrum SCADA solutions to help monitor and manage critical infrastructure. Several manufacturers (including FreeWave Technologies) offer spread spectrum radios capable of retrieving data from remote locations. And although wireless IO (input/output) has been available, only recently have both capabilities been offered in one communication solution.
7) SCADA can automate cathodic protection. It is very easy to install an automated cathodic protection system if a company has a SCADA system. However, it is not necessary to have one to implement remote monitoring of cathodic protection. Many companies own and operate their own SCADA network and can leverage their existing capital investment in SCADA through extending the data communication network further to include cathodic protection. For companies that do not currently own a SCADA system, small-scale cathodic protection SCADA systems are implemented with minimal investment in readily available software, off-the-shelf personal computers, and the services of internal or external local integration companies.
8) SCADA systems help the smart grid. As the need for reliable, real-time data communication in mission-critical SCADA systems to monitor and control distribution automation as part of the smart grid continues to increase, electric power utilities seek new and better ways to improve communications infrastructure, adding reliability and security. Broad, integrated solutions can meet the emerging demands in electric power, including frequency hopping spread spectrum (FHSS) serial radios that hop 500 times per second (“he who hops fastest wins”), along with I/O and high throughput Ethernet radios with encryption and easy-to-use interfaces.
9) Seek easy-to-use SCADA software. Field technician or utility operators implementing and using a SCADA network system for data communications want a simplified, rapid setup and easy management of a network. That includes ability to manage multiple frequencies and multiple networks within one system. A centralized storage and management center provides easy access to system configuration and diagnostics data. Technicians in remote or harsh weather environments need robust reporting capabilities. Software like FreeWave’s ToolSuite can manage data communication diagnostics and configuration.
Table: Wireless data comparison
Technology Fee Range Speed
UHF/VHF N 30 mi 9.6 kbps
CDPD Y Limited 19.2 kbps
IEEE 802.11 N 200 ft 11.0 mbps
Spread spectrum N >30 mi 115.2 kbps
Bluetooth N 50 ft 721 kbps
Licensed Y 20 mi 19.2 kbps
Microwave ? Many mi 300,000 km/s
Source: FreeWave Technologies and Control Engineering
Dan Steele is business development executive, FreeWave Technologies Inc., www.freewave.com.
Edited by Mark T. Hoske, CFE Media, Control Engineering, www.controleng.com.