Ethernet and wireless I/O can help improve network operability to help you make more informed decisions better see remote site performance.

By Curt Goldman, FreeWave Technologies

The way organizations do business has changed. New communication methods and real-time data transfers via EtherNet/IP™ are driving businesses to stay better connected and more informed about field operations. But to design an effective communication system for SCADA applications, you must first understand the objectives for the system. How much data is to be moved, how often it is to be moved, from where is it coming, and to where is it going? These are important factors.

Frequently, a company with geographically dispersed assets needs cost-effective, technically feasible ways to implement reliable, long-range data communications. In addition, critical sensor and polling data is needed back at a central location for real-time monitoring and control.

This is where EtherNet/IP can help. It uses TCP/IP for general information exchange services and UDP/IP for I/O messaging services for control applications.

These services help to automate data exchange, and to control and monitor application capabilities. EtherNet/IP connects computers, drivers, controllers, I/O, and more to enterprise network systems.

Benefits of Going Wireless

Figure 1. This image illustrates the communication pathway using wireless Ethernet and wireless I/O for water wastewater SCADA network applications.

Wireless data radio communication technologies can offer measurable engineering, installation and logistics cost savings. It also can improve the frequency and reliability of field data collection. For SCADA applications, wireless communication infrastructures using wireless Ethernet and I/O enable dependable access to real-time information for establishing and maintaining field operations (see Figure 1).

For example, Ethernet and Wireless I/O data radio solutions from Rockwell Automation Encompass™ Product Partner FreeWave Technologies’, combined with Allen-Bradley® programmable controllers from Rockwell Automation, can address remote monitoring and control issues previously deemed cost prohibitive, not technically feasible or lacking in sufficient reliability.

Wireless Ethernet data radios provide a high-throughput “backbone,” enabling field assets to be polled very quickly. This increases the data–collection frequency and maximizes efficiency. Wireless Ethernet units have excellent range and enough bandwidth to transmit high volumes of data, minimizing the number of repeaters needed to cover many miles.

Using high-throughput Ethernet radios as a backbone between repeaters enables IP addressability for all data traveling through the network. Greater interoperability exists between the hardware and software components within the network infrastructure. In addition, multiple users and applications can run on the same infrastructure.

Wireless I/O products provide more data to the user with less work, including scalable digital and analog I/O capabilities. This allows users to have multiple control and monitoring options for each device.

Figure 2. Programmable controller capabilities are extended with a wireless I/O expansion module via wireless Ethernet radio.

Adopting an expandable platform often is justified by additional monitoring mandated by the government, new process technologies that require more points for monitoring and control for higher process output, and for peace of mind knowing that more points can easily be added in the future. Wireless I/O also can integrate directly into a larger wireless SCADA network to connect the corporate office with field controllers, process measurements and control points (see Figure 2).

Ultimately, the benefits of wireless Ethernet and I/O are tied to maximizing the value of a SCADA system. By having more I/O points along the system and high-throughput Ethernet capabilities to bring the data back to a host SCADA network, users have more control and increased awareness of what’s happening in their operations.

Working with a Vendor

When selecting a technology for network data communications, work with a technology vendor committed to your organization’s success. This includes offers for free path study services, expert systems engineering capabilities and customer support and network troubleshooting services.

Many technologies can satisfy the needs for any particular SCADA application, but to implement a fully integrated system means working side-by-side with the vendor to ensure reliability, data security and stress-free manageability.

Other Factors to Consider

1. Assess your technology options for a SCADA network. When it’s time to research all of the options, learn what’s available now and in the future. “Buyer beware” is a popular saying for a reason. Talk with colleagues within your organizations, attend tradeshows and events, and proactively contact manufacturers. Not all manufacturers know your specific situation and needs.

Today’s communication products vary in every possible way. Each manufacturer and/or technology has advantages and disadvantages. It’'s also very important to remember that oftentimes a single product cannot meet all of your needs. This is why the most important starting point of creating a SCADA system network is to identify your needs, goals and limitations.

2. Reduce costs. While some companies will want to continue preserving their existing investments of mixed technologies, there are clear advantages for communication professionals in selecting wireless technologies over wired alternatives for SCADA systems. The most intuitive advantage is reduced labor and material costs required to hardwire remote assets. Installation costs are a growing concern for companies as labor rates continue to rise and labor pools decline.

• You can gain additional savings via deployment speed. Wired systems can take days or weeks to be installed properly. Conversely, wireless networks generally require only the end points to be installed, saving time and costs.
• Networks should scale gracefully as the number of end-points increase. Scalability is the second biggest advantage of wireless compared to hardwire after installation savings.
• You can implement wireless slowly over time and integrate it into existing systems.

3. Increase SCADA system flexibility. Wireless radio communications and their advanced flexibility offer technological benefits to new and existing SCADA systems. For example, water wastewater applications have generation/distribution operations, lift stations, system monitoring and treatment facility systems in place (or planned) to meet a community’s population growth and service areas to meet future requirements.

Better SCADA Operability

To successfully design and implement a communication system for SCADA applications, it’s important to know the objectives for the network. With proper planning, Ethernet and wireless I/O communications can effectively improve SCADA network operability and enhance the functionality of programmable controllers. This results in the ability to make more informed decisions on a real-time basis and increases awareness of how field assets are performing.

FreeWave Technologies, Inc., based in Boulder, Colo., is a participating Encompass™ Product Partner in the Rockwell Automation PartnerNetwork™. FreeWave supplies license-free and licensed radios.

Freewave Technologies, Inc.