I read your article Users want an industrial wireless standard with enthusiasm since I’ve struggled with the promise of this technology in the workplace for several years. As I read through the discussion I realized that perhaps I’d missed the boat on wireless. Working with colleagues in house we’ve as much as dismissed that application of wireless as outlined for the very reason you eluded to – it’s just not mature enough at this time and we are too risk adverse to experiment with it. Instead we’ve focused on where and how wireless can help, and what protocol to use.
Our internal customers were asking us for a solution to allow high value information such as offsite analytical, or Marine Vapor Recovery Unit (MVRU) information to find its way into our data historian. Typically the cost to run traditional ‘conduit and wire’ infrastructure far exceeds the cost of the primary application (one example is an estimated cost of ~$300M in order to see the flow rate of purchased nitrogen into the plant from a skid at battery limits, later done for ~$5M using wireless). We began to see products aimed at these types of applications using FHSS (frequency hopping spread spectrum) radios. However, some of our own group found major objections to connecting these devices to our ‘control platform’.
Security is a major concern with not only our IT group, but our controls group as well. The idea of introducing an ‘external’ source of data onto our controls platform ran firmly into a brick wall, and that was okay as it turned out. As a group we agree that wireless isn’t ready to plug-in to our DCS or other controls networks. Since this is the primary way to make process data available to our data historian so that staff could view the data, we had to find another pathway.
Working with our IT group we placed the ‘gateway’ unit directly onto an Ethernet hub. The gateway is able to talk various protocols and ours was enabled to allow information to be available to our data historian (a driver was required for the historian) and data was made available to all with access to our historian. With the installation of the gateway unit additional outlaying equipment with ‘high value’ information became incrementally inexpensive to install. Additionally, our IT group has dedicated a fiber for this application providing isolation from other network devices and improved security risk.
Using this type of equipment and architecture we are now proposing the installation of a ‘maintenance network’ for our tank gauging and inventory control system. This would allow the technicians to troubleshoot and configure any device on the tank gauging network from their shop instead of in 100 degree plus heat or in the rain.
Additionally, our instrument technicians are now using a pair of FHSS radios for troubleshooting in place of the old locally installed chart recorder. This is for systems or applications where sufficient information isn’t available, or more information is desired. The receiving radio is set up in the instrument shop where data is recorded and analyzed.
The focus of your article is on the development and adoption of a wireless standard which can be implemented for process control. We will watch this development with interest in the coming years and perhaps even try it out at some point. For now we’ll continue to capture these high value applications our customers are asking for while balancing both security issues and our risk profile with the integration of wireless into our business.
Sr. Eng. I&PCR Group
Flint Hills Resources
Corpus Christi, Tx.