ISA100.11a at work
06 August 2010
The ISA100 Wireless Compliance Institute has installed a multi-vendor User Test of the technology at an Arkema plant in Crosby, Texas, demonstrating interoperability among devices from multiple vendors. Arkema is a €5.6B diversified global chemicals manufacturer with 80 industrial sites in more than 40 countries and six research and development centres.
Arkema’s site in Crosby produces liquid organic peroxides that are used primarily to produce plastic resins, polystyrene, polyethylene, polypropylene, PVC and polyester reinforced fibreglass, and acrylic resins.
The Crosby plant was built in stages beginning in the late 1960s, and has three different generations of technology. They need data from all of these systems in one control room.
ISA100.11a wireless is seen as a practical method of retrofitting sensors plant-wide into a diverse range of applications and presenting the data centrally. Most of the sensors are outdoors, where cabling for sensors can be very expensive.
Numerous applications for ISA100.11a were identified in a comprehensive review of the site and four applications were chosen for an initial User Test: A pressure sensor on a water tank, temperature monitoring in a cold storage area, a tank level sensor, and a gas sensor.
The system was designed to cover the entire site. Wireless coverage is envisioned over an area comprising more than 50 acres, with wireless sensors installed as needed throughout the operation, and the entire site is covered by two backbone connections.
An infrastructure was installed including two ISA100.11a backbone routers, which act as wireless access points covering the site. A WiFi connection between the backbone routers simplifies the installation, so that the remote backbone router does not need a wired connection back to the host. In the initial configuration, seven of the nine transmitters were able to establish strong connections directly to the backbone. The remaining two transmitters are remotely located and need to connect by sensor meshing through other transmitters. The sensor mesh provides redundancy and also extends coverage to the edges of the facility. All deployed transmitters at Arkema have routing capability, so as more transmitters are added the number of possible mesh connections will increase exponentially.
All transmitters installed at Arkema have been tested for ISA100.11a compliance using a noncommercial version of the Wireless Compliance Institute’s Device Interoperability Test Kit. This hardware/software tool uses XML scripts to emulate the operation of an ISA100.11a system manager in a transparent and vendor-independent manner.
To demonstrate the concept of plant-wide coverage from two access points, the initial transmitters are installed toward the periphery of the operation. The backbone routers were placed based on a visual inspection of the site, without a radio survey of any kind. Radio ranges of 100-200 meters are being achieved as expected. The infrastructure components are intended to cover the entire facility, with a third backbone router planned to the south of the other two. This will provide full coverage of the entire site, with many areas of interest having two direct backbone connections. The meshing capabilities in the ISA100.11a standard will provide redundancy in locations where only one direct connection is available, and network access in the few locations where a direct connection is unavailable.
The system has been operating at Arkema since 19 September 2009, ten days after the ISA100.11a standard was ratified. The parallel development of the standard, stacks, transmitters, infrastructure, and compliance tools made it possible to install a useful, interoperable, multi-vendor system in this very short time.
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