November/December 2011
Cover Story

Finding the unexpected benefits of wireless

A solid wireless foundation supports a growing number of applications

Fast Forward

  • HollyFrontier's El Dorado refinery found several uses for its industrial wireless mesh network on top of its original pressure-monitoring application.
  • System flexibility has helped the refinery expand its network with far more ease than a wired infrastructure.
  • With the successful implementation of its network, HollyFrontier plans to expand the network to other areas of its facility.
By Andrew Nolan

When industrial wireless began inching its way into the process industries a few years ago, saving money by eliminating hard-wiring costs was probably the most talked-about benefit. Shortly after that, the enabling of a mobile workforce started becoming a bigger part of the conversation. Then, it evolved to include the ability to use information gathered from wireless to optimize operations.

cover1Truly, as wireless has taken a greater hold in plants, more benefits have revealed themselves to manufacturers. The latest of these appears to be flexibility; that is, many plant managers are finding the nature of wireless technology allows them to address applications other than those for which they were originally installed to improve operations.

One example of this can be found at the HollyFrontier's El Dorado refinery in southeast Kansas, which discovered several uses for its industrial wireless mesh network on top of its original application. Along with direct access to Cushing, Okla.-a major crude oil hub-the El Dorado refinery is one of the largest refineries in the Plains and Rocky Mountain regions.

The refinery originally implemented a network of wireless transmitters as part of an initiative to effectively monitor pressures across the facility's flare system. The plant's wired monitoring system could not cost-effectively reach remote monitoring locations for a facility spanning almost one square mile. As a result, plant personnel spent considerable amounts of time investigating equipment in their respective units.

The logical solution, of course, was to research wireless possibilities. Given the sheer distance that needed to be covered, eliminating the costs for hard wiring was the easiest way to make the project more feasible. But the El Dorado Refinery would also later discover the flexibility of a robust mesh network would translate into other benefits.

Laying the groundwork

The first implementation steps involved directly interviewing plant personnel from various units across the facility to determine where wireless implementations could make the most impact. The company developed an informational guide to help employees understand wireless capabilities and what the company hoped to accomplish with such applications.

Plant personnel developed estimates for wired and wireless engineering, equipment and installation costs, and broke down competitive wireless technologies from suppliers. The refinery diligently researched technologies, hosted on-site visits with vendors, and obtained customer testimonials to educate themselves on both of the technologies available to determine which one was the best fit for their situation.

Specific criteria were considered for their wireless implementation:

  • Cost - With future expansion in mind, its transmitters needed to have a low future capital cost as instruments were added to the mesh network. The incremental cost of each additional transmitter becomes significant as the network grows.
  • Network speed and expandability - The El Dorado refinery needed a network that would have little or no network latency but also one what would remain unified no matter how large it became. With data being sent back and forth constantly, speed and reliability was of the utmost importance.
  • Integration - The refinery had little time for compatibility problems and wanted its network to integrate smoothly with its distributed control system (DCS). Furthermore, the El Dorado refinery had a future vision of Wi-Fi-centered implementations, including mobile operator stations and live video cameras, which it wanted to have the ability to add to the network with no additional infrastructure costs.


After reviewing exactly what wireless implementation it would need and vetting its options, HollyFrontier's El Dorado refinery worked with Honeywell to implement a wireless mesh network across the refinery. Not only would installing wireless pressure transmitters allow the refinery to quickly detect pressure changes across the facility, it also allowed the company to save manpower and time while improving decision making at the refinery. The refinery's existing system architecture made the implementation and integration of the wireless network much simpler, considering the refinery already operated a Honeywell DCS.

The El Dorado refinery's wireless mesh network was formed with industrial wireless nodes, called multinodes, which self-discover to create an industrial mesh network within seconds and expand the process control network into the field. A self-healing system, each individual multinode communicates with two others in the event of interference or unforeseen error, with each transmitter doing the same. Additionally, the refinery saw the system's gateway as the single point of net­work instability and installed two units to promote redundancy and eliminate the potential of failure.

Before the implementation of the actual wireless mesh network, the refinery conducted a site survey to determine the best placement of multinodes, transmitters, and gateways, and to gauge appropriate signal strength. Using an initial implementation of eight multinodes, two gateways and 17 wireless pressure transmitters, El Dorado formed all of its operating process units into a single, seamless network.


The architecture is also multi-functional and supports Wi-Fi devices as well as wireless transmitters. With this functionality comes several direct benefits:

  • Engineers can connect ISA100 hardware compliant wireless I/O devices and Wi-Fi clients to the control system.
  • Network administrators can utilize communication between the DCS and wireless system to add, configure, and monitor wireless devices within the existing control system.
  • Native integration of the wireless system with the DCS reduces device commissioning time and improves reliability/scalability with built-in redundancy.

Project results and more unexpected benefits

After the system was installed, the El Dorado refinery saw numerous benefits including:

  • A reduction in the engineering time spent locating the precise source of increased pressure loads with the new wireless indications in place
  • A 50% reduction in the cost to install a wireless transmitter compared to traditional wired transmitters
  • A scalable infrastructure that is expandable to areas presently without coverage

But the infrastructure also has allowed for rapid, cost-effective responses to other monitoring requirements as they have since arisen. Personnel, for instance, can add indication-only transmitters in less than a day, even in remote locations like the tops of tanks or reactors, thus increasing the amount of measurement points in the facility.

Engineering time for expansion of its network has also diminished, and adding transmitters is no longer a significant time investment. In the past, adding a transmitter required an engineer walking out conduit routes and putting together wiring diagrams to map out a new installation. With wireless, the same engineer simply marks up a process and instrumentation diagram and issues a construction package in a fraction of the time.

System flexibility has also helped the refinery expand the network with far more ease than any wired solution could have offered. Since its initial installation, it has more than doubled the number of wireless transmitters in operation, with additional applications being considered every day. For instance, with the ability to connect multiple sensors like thermocouples or resistance temperature detectors to a single transmitter, the refinery is able to monitor separate process variables and save on transmitter costs.

One application in particular captures the ease and simplicity of wireless. The El Dorado refinery wanted to monitor temperatures on a 60-foot hydrogen line, which operators were concerned was getting too hot. In an implementation that took less than 36 hours from conception to installation, the refinery set up a system of four transmitters and 12 magnetic thermocouples that simultaneously measured the line temperature while wirelessly sending back data across the network. In addition to capital savings, the refinery mitigated the time and engineering oversight needed for the project.

The El Dorado facility now has 40 wireless transmitters installed, monitoring 60 points. And without having to add any additional multinodes, it is adding more applications to the wireless system at an impressive pace. While wireless has an initial capital investment cost, an inherent benefit is the more transmitters that are added, the more savings a plant realizes over wired transmitters. El Dorado, for instance, broke even on its investment at 40 transmitters and, given its fairly large size, the breakeven point for smaller plants is even lower.


Lessons learned

HollyFrontier's El Dorado refinery pulled several key lessons from the experience that have improved the operation of its wireless network and helped create best practices for future industrial wireless implementations.

In terms of installation, it is important to take multinode placement into consideration when estimating project costs. Oftentimes, the predicted point of installation may differ from the actual point of installation due to unforeseen problems like tower disturbances, which can alter installation costs. By moving further from a power supply, for instance, the cost of installation may end up being higher than anticipated.

It is also important to realize wireless certainly has its place, but is not always appropriate for every application. There can be instances at facilities where the costs of wiring a transmitter may actually be more cost-effective than installing a wireless transmitter. Allowing wired and wireless devices to work in tandem and giving thought to each installation will garner the most efficient and cost-effective solution for a facility.

But perhaps the most critical element that contributed to the project's success was the fact that the refinery began with a clear vision of what it wanted to accomplish. After starting with a modest application and realizing the time reductions and reduced engineering and capital costs associated with a wireless infrastructure, the El Dorado refinery quickly expanded its network throughout its facility and continues to plan for additional applications.

With the successful implementation of its wireless infrastructure, the El Dorado refinery plans to continue to expand its network and will extend its reach to areas of the El Dorado facility that are not currently covered. The refinery may also utilize its wireless network to further an energy-reduction initiative in which it must monitor the run status of hundreds of steam turbines plant-wide-a task that would be cost-prohibitive with a traditional wired system.

Finally, the refinery also sees an opportunity for its wireless network to make an impact when it comes to safety and security. As security requirements for plants continue to grow and become more stringent, it is necessary to improve capabilities in securing a facility. In particular, the El Dorado refinery sees an opportunity in monitoring its vast perimeter with wireless video capabilities and securing its fences by extending its wireless network.

What started as an application to improve pressure monitoring capabilities quickly turned into a refinery-wide solution that helps personnel improve overall safety, reliability, and efficiency-a theme that continues to manifest itself throughout the process industry. The value of implementing a wireless infrastructure is clear, but it is the flexibility and unexpected benefits associated with the addition that continues to drive the adoption of wireless in the process industry. Much like HollyFrontier's El Dorado refinery, facilities are finding broader applications for wireless technologies once they are installed and novel uses continue to reveal themselves. Industrial wireless has proven to be a flexible medium since its inception, and examples like HollyFrontier's El Dorado refinery illustrate a continued evolution of how it can be applied.


Andrew Nolan ( is the Americas sales leader for wireless at Honeywell Process Solutions and is based in the Atlanta area. In his Honeywell career, he has held technical, functional management, and project management roles.