When the Heat is on, Control with Wireless

Emerson’s Michael Pearson, a member of the Rosemount Temperature team, provides today’s guest post and highlights how wireless instrumentation can avoid issues with process-caused damaged wiring and other causes.

Many temperature measurement challenges exist when monitoring high temperature assets including heat damage, moving equipment, and high electromagnetic interference (EMI). North Star Bluescope Steel had all of these problems and more when measuring temperatures on their Electric Arc Furnaces. High temperatures and molten slag would destroy Thermocouple wiring on a regular basis. They measured 28 points on the furnace, most of which were used for control, and their only solution was shutting down the furnace often to replace the wire.

By implementing an IEC 62591 WirelessHART-based solution using Emerson wireless instrumentation, the steel manufacturer was able to reduce or eliminate all of these wiring and measurement challenges, resulting in greatly reduced maintenance costs, and additional throughput.

Wireless technology has had growing acceptance in the process industry over the last several years. Initially, some people were skeptical of the safety and reliability of wireless. Others had to weigh the pros and cons of the various communication standards, such as IEC 62591 WirelessHART and ISA 100.3. Others simply couldn’t think of useful applications for the technology. Now that the technology has been available for many years and proven its safety and reliability, it has become widely accepted in hundreds of applications in every major process industry sector. Wireless has had particular success in applications where traditional measurements were extremely difficult or even impossible.

Areas with high heat are one application where wireless temperature monitoring has been extremely useful. By mounting the transmitter close to the process, sensor wiring is greatly reduced or eliminated. This leads to reduced heat damage and less sensor drift and EMI interference. It also eliminates 100% of remote marshalling and junction boxes. Because of this lower installation complexity and ongoing maintenance, measurements are more accurate and downtime is reduced.

It’s also important to note that Wireless is not just for monitoring. Wireless can be and is used for control. WirelessHART is particularly well designed for control. By using self-organizing, mesh technology, utilizing multiple communication paths–99.9% data reliability is achieved. It also uses 128-bit data encryption to ensure data is securely transmitted. Additional reliability can be attained by installing redundant wireless gateways and controllers to ensure complete data redundancy.

Wireless technology has proven itself in the process industry. More and more process manufacturers are choosing to use it for tough applications as well as everyday applications. As North Star Bluescope Steel discovered, wireless technology can be particularly useful in areas with high heat. With hundreds of possibilities of monitoring and control applications, the question is not if, but rather where and how much your plant can deploy and benefit from it.

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Update: Here’s Michael’s presentation on the subject from the recent Emerson Exchange conference:

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