By Dan Hebert, PE
The phone rings in the middle of the night. It's the third shift operator, telling you that there's been a process upset. Do you get out of bed, dress and drive 25 miles to the plant? No, instead you use your Blackberry and check what's happening, make a few changes to process setpoints and watch the system recover. Far fetched? Not at all.
Mohawk Fine Papers instituted such a system. On a Sunday afternoon at home with a single click of a Blackberry, a Mohawk engineer can tell that the paper machine is up, running at a particular speed and consuming so much energy. This is part of the "Information Everywhere" project that Mohawk implemented in 2009.
"Information everywhere is an important part of our continual improvement efforts," says Ben Whitaker, manager of enterprise process reengineering at Mohawk. "This project has played an important role in Mohawk's overall 2009 improvement in machine output, customer satisfaction and energy consumption." (To read more about Mohawk's mobile application powered by Transpara (www.Transpara.com), see the "Information Everywhere on a Blackberry") at the end of this article.
Working with Wireless
While it may not work from home, Novartis, a biotech manufacturer in Huningue, France, uses a different kind of mobile workstation to provide the flexibility needed to control their manufacturing processes.
Novartis has been using wireless since 2000. In 2008, when migrating to version 9 of Emerson Process Management's (www.emersonprocessmanagement.com) DeltaV system, the company added integrated Wi-Fi and wireless security. In 2009, Novartis expanded the wireless architecture with additional Wi-Fi access points, implementing a complete mobile wireless solution. "The most recent developments to Emerson's DeltaV system have enabled us to implement a plant-wide wireless solution," says Philippe Heitz, head of engineering.
The wireless network includes 17 mobile operator stations (see Figure 1) and 100 DeltaV controllers spread over two systems. The first system controls the upstream process of cell cultivation and harvesting, and the second controls the downstream phase of purification and freezing. Both systems will soon be interconnected using DeltaV ZONE, a software and hardware solution for connecting two automation platforms.
To meet the standards required for sterile zones, the mobile operator stations each have a stainless steel enclosure that houses the central processing unit. The devices are equipped with a USB connection to the usual keyboard, monitor and mouse for this type of environment. Each station connects to the network via Wi-Fi access points.
Operators can move from one level to another with their mobile station and still maintain an overview of the process. This has not only significantly improved operator efficiency, but also has made it possible to reduce the number of required workstations by 50%. A further benefit is that when a new product is being launched or a recipe changed, the mobile stations can be moved throughout the plant, obviating the need to install new operator stations.
"Because of the wireless network, we don't need to systematically invest in new control stations, even if production requires a change to the plant equipment or layout," explains Patrick Boschert, automation expert, at Novartis. "Thanks to wireless technology, Novartis cut in half the number of operator workstations required for the production area."
Another type of wireless solution doesn'- mobilize the worker, but instead the asset that is being monitored. Yokogawa (www.yokogawa.com) has implemented a wireless mobility solution for a life sciences client using 900 MHz meshing I/O radios. Their client has thousands of identical refrigeration units on a large campus. Two or three analog inputs plus a digital input are monitored on each unit.
The existing system hardwired these inputs into local data acquisition hardware, which was then collected via Ethernet over the corporate LAN by a SCADA monitoring system. These units were frequently relocated, which required rewiring of inputs and manual reassignment of tags within the SCADA database.
In the new system, a 900 mHz I/O radio is mounted with each process unit, allowing analog and digital inputs to be terminated directly on the process unit. Using the wireless network, inputs are then transmitted to centrally located wireless gateways and data concentrators. The inputs are then collected via Modbus TCP by the existing SCADA system.
Refrigeration units can now be moved anywhere on campus without making changes to the wireless network or the SCADA system database. The 900 MHz mesh network is self-organizing and self-healing, making network management more efficient.
Table PCs are the Writing on the Wall
Honeywell Automation and Control Solutions (http://acscorp.honeywell.com) has two installations where tablet PCs are being used as HMIs. Neither customer can be named, but the examples are illustrative of how the technology can be used to improve process plant operations.
The first is a refinery in Big Spring, Texas, that uses wireless to allow operators to access their operating console directly from the field via a tablet PC. Wireless also allows the plant's mobile workforce to send data collected during rounds to the automation system via handheld devices.