A World Without Wires?

Aug. 30, 2005
The future is now for process monitoring via wireless instrumentation, while wireless process control looms.
By Paul Thomas, Managing EditorThe general public has grown accustomed to wireless technology through the use of cell phones, wireless PDAs and WiFi-enabled computers. Meanwhile, pharmaceutical manufacturers are just beginning to dip their toes in the wireless waters. Only now are wireless technologies becoming practical and robust enough for adoption on shop floors and in warehouses.But there is little consistency of equipment offerings. “Most vendors are utilizing a scattershot approach to target any and all industries showing interest in wireless,” says Jake Millette, an analyst with Venture Development Corp. (Natick, Mass.). “Pharma-specific trends or vendors concentrating only on this market have just not materialized yet.”From the manufacturer’s perspective, validation and collecting and integrating wireless data with current IT systems are real concerns. Regulatory prodding and high-profile applications have ushered in the era of Radio frequency identification (RFID), a wireless application for product track and trace purposes. But for ambient monitoring or process monitoring in the plant, the wireless explosion has yet to materialize. For process control, adoption is much further off.In 2004, the pharmaceutical industry made up just 4.3% of total purchases in the as-of-yet small — $154.1 million — market for wireless monitoring and control products in discrete and process manufacturing, according to Venture Development. However, that figure is expected to increase to 5.1% of a total $419.3 million market in 2007, and rise measurably thereafter.“We’ll see an accelerated acceptance of wireless in the pharmaceutical industry,” says Frank Williams, VP of Elpro Technologies (Brisbane, Australia), a provider of wireless modems, I/Os and other devices. Elpro specializes in monitoring valves, remote temperatures and tank levels, and has done applications with Merck, Pfizer, Pharmacia and Roche, Williams says. “There’s always a gestation period that must occur with new technology,” he adds, but more aggressive manufacturers are truncating the typical two- or three-year implementation cycle to 18 months.“We’re not really doing anything with wireless right now,” says one pharmaceutical process control specialist. “But I see us making the leap to wireless fairly soon, probably for monitoring remote areas for materials storage.”A hodge-podge of pharma applicationsIndeed, for remote storage areas and large warehouses where wiring is difficult and “line of sight” is easy, wireless makes sense, especially for ambient temperature and humidity monitoring.But wireless sensors can also keep close tabs on pharmaceutical processes, particularly those that involve rotating or mobile equipment. And as the industry moves toward modular construction and nimble manufacturing practices, ready-to-move wireless equipment will gain more appeal. Wireless technology will enable many process analytical technologies, and dovetail nicely with FDA’s PAT initiative.Manufacturers are experimenting with unique in-process uses, and vendors are diversifying their products:
  • Abbott Laboratories suspected that an accumulation table on one of its packaging lines was causing slight damage to bottles and vials. Abbott sent samples of the containers to Sensor Wireless, Inc. (Charlottetown, P.E., Canada), which made an acrylic replica embedded with tiny accelerometers on a circuitboard. Abbott ran the replica through its bottling line, and took readings using handheld devices to measure the impact of bottles jostling against one another. Abbott used the data to adjust its line speed and correct the problem, says Tammy Wall, Sensor Wireless’s VP of operations.

  • Mathis Instruments (Fredericton, N.B., Canada) recently unveiled a wireless version of its thermal effusivity sensor for monitoring powder blend uniformity. AstraZeneca studies showed that the sensor could operate reliably transmitting up to 50 feet and through three different walls, says company president Nancy Mathis. Mathis envisions that companies will use the device for process control as well as monitoring — stopping a blend when the end point has been determined, for instance. “The control stuff is there in terms of our capabilities,” she says. “But it’s not quite there for users’ readiness.” Companies need time to come to trust wireless sensors and measure them against other control devices, she says.

  • Accutech (Hudson, Mass.) markets a wireless ultrasonic sensor for clean-in-place monitoring. The sensor resides on the outside wall of a vessel, and creates an “ultrasonic signature pattern” of the interior that indicates whether cleaning has been done properly. The company also makes a self-contained temperature probe that is mounted on rotating dryers for measuring batch temperatures, which can then be correlated to the dryness of the cake inside. It also has a line of wireless sensors to monitor safety showers and eye-wash stations.

  • Honeywell offers a light-induced fluorescence sensor that mounts on rotating blenders, and has installed 17 units at various drug facilities, says Ted Dimm, Honeywell business director. The sensor measures the degree of fluorescent light emanating from a blend to determine when mixing is complete.
The need for networksSensors are typically deployed as individual nodes that transmit point-to-point with radio receivers, often linked to company PCs or PLCs. Many sensors are battery-powered and self-transmitting, though the most cost-effective means for wireless transmission is through wireless I/O devices and modems rather than through all-in-one devices.Entire networks of similar or dissimilar devices all transmitting to one or a few antennae are the holy grail. This would allow not only for the easy collection of data and more centralized process monitoring, but also for additional sensors and applications to be installed on an as-needed basis.Wireless “mesh” networks, in which the devices send and receive radio signals among each other, will allow for increased redundancy and a greater likelihood that each piece of data will reach its ultimate destination. Simple networks of like devices are coming on line as manufacturers realize their benefits, one being that they’re easy to install. Veriteq Instruments (Richmond, B.C., Canada) recently conducted a survey among validation service firms and pharmaceutical manufacturers, comparing the time and labor requirements of temperature mapping using thermocouple-based systems and wireless systems. For a 32-point mapping (i.e., 32 sensors were placed) of a 2,000-square-foot room, wireless implementation took an average of 70% less time and labor. Sensor placement, for example, was just 15 minutes, as compared to 43 minutes for the thermocouple system. Post-calibration was 30 minutes, versus 90 minutes for the traditional system.Can they do control?But networks of dissimilar devices or mesh networks require large amounts of bandwidth and power, and interoperability among devices — wireless instruments from different vendors, even if they operate on the same frequency, do not always work together. Add to this the fact that wireless equipment is slow to transmit data in comparison to wired, and that radio transmission is subject to interference and interrupted transmission, you begin to understand manufacturers’ wait-and-see approach. This is especially true when it comes to using wireless as a means of process control. “Radio is not 100% reliable,” says Kevin Bull, CEO and cofounder of Veriteq, a maker of wireless data loggers for temperature and humidity. “It’s a very conservative industry, and there’s a justifiable reluctance to have wireless in a process control loop.”“A good portion of our customers that would like to do wireless control in the next few years,” says David Kaufman, a business development director with Honeywell. In order for that to happen, the speed, reliability and security of data transfer will need to be greatly improved. But it will happen, says Kaufman. “There are a lot of smart people out there working on this,” he says.Increased standardization of protocols for equipment and transmission frequencies may address some of these flaws. Standard protocols for wireless transmissions have been developed by industry standards groups comprising vendors and users. Bluetooth and WiFi are two of the better known, yet these are seen as better for voice and graphics applications. ZigBee is a low-power, slow-data standard that has many supporters for remote monitoring. Predictable, long-lasting power is key for wireless monitoring, and ZigBee supports battery life of 1,000 days or more.Members of IEEE, ISA and WINA are currently working together on standards that they hope will gain acceptance by IEC. Just last spring, a new ISA standards committee, ISA-SP100, was formed to further standards and technical documentation in the automation and control arena. Project teams have formed to focus on issues such as education, guidance documentation, and interoperability of sensor networks within the industrial environment.Frequency hoppingNot everyone believes standards are needed. FCC has already designated license-free bandwidths for Industrial, Scientific and Medical (ISM) instrumentation use, and this should be enough, says Gene Yon, president of Adaptive Instruments/Accutech, Inc. “We don’t need a standard in industry,” says Yon. “What’s holding wireless back is that a lot of people are using a lack of standards as a retrograding factor.”Accutech favors FHSS, or frequency hopping spread spectrum, which utilizes a range of randomly-patterned frequencies to improve the quality of signal transmission and make it more difficult for outside parties to “listen in” on a given frequency. ZigBee, for instance, is unreliable and unsafe, Yon argues. A standards debate? “It’s pretty well resolved in our view,” says Yon. But with the rise of wireless networks and the need for improved interfacing between equipment, standards will be critical. They just need to be kept in perspective, says Bull of Veriteq, which developed its own proprietary protocol. “There was no off-the-shelf protocol to handle what we needed,” he says. “Standards are always a good thing, but they often don’t address unique requirements.”The day will come when roving bands of miniaturized “motes” or smart sensors will monitor pharmaceutical processes from within, transmitting blend characteristics as compounds are mixed, or measuring hardness or moisture content as tablets are pressed. Until that day, wireless instrumentation could serve as an inexpensive and effective means of ambient and on-line process monitoring, paving the way for the wireless world of tomorrow.

Cutting the Cord for Temperature Monitoring

Roche Diagnostics has created a wave new world in its Indianapolis warehouses

By Paul Thomas, Managing Editor

Two years ago, Roche Diagnostics decided to upgrade the temperature monitoring in the warehouses of its Indianapolis facility. It wanted a reliable, networked system of sensors that could be installed quickly and automatically stream data to a central process control system for optimal monitoring and archiving.

Site managers had considered a wired application. After all, the manufacturing area had recently been equipped with an integrated system of electronic temperature and humidity monitors, which was working well.

But wireless won out for the warehouses because it could change with the facility. If, for example, Roche wanted to reconfigure its warehouse operations or move equipment or coolers, wireless instruments could move, too. “We needed to design for flexibility, not just optimization,” says Chris Upwards, director of distribution at the facility.

Roche turned to Honeywell, which it had partnered with on an Experion Process Knowledge Systems installations to control operations at the site. A decision was made to install another Experion platform for warehouse operations, and to allow Honeywell engineers to provide a temperature solution for the warehouses that would link to Experion.

The cost would be higher than initially expected, but management approved it based on the fact that the system could grow with the facility and serve as a model for future applications. A 10-member team of Honeywell experts, an outside validation consultant, and key Roche IT and operations personnel was set up to tackle the project.

Easy does it

Sensor installation may have been the easiest part of the implementation—requiring roughly half a day for each warehouse. Roche installed nearly 100 Honeywell XYR500 wireless temperature sensors, as well as some strategically placed humidity sensors made by third-party manufacturers, among the three warehouses. Most sensors weigh less than a pound and were affixed to interior walls with simple mounting brackets.

Some of the sensors were mounted inside coolers, which must be kept between 2° and 8° C. For freezers requiring temperatures consistently well below zero, to prevent sensor damage transmitters were placed outside and connected to internal probes. “We extended the wiring from the outside of the freezer where the transmitters are mounted,” says Larry Mills, senior project leader, service operations for Honeywell. “The probes are plug-in. If one of them were to go bad, we could unplug it very easily and replace it pretty quickly.”

Temperature probes were also used for one room designated for hazardous materials storage. “The toughest part was just pulling the wire through the conduit to connect the sensor to the wireless transmitter,” says Mills.

Each building was equipped with base radios receiving transmissions from the network. Like any radio communication, sensors and bases require short distances, line of sight and permeable materials to communicate. One 90,000-square-foot warehouse sectioned by concrete walls required three bases.

Honeywell’s wireless equipment transmits by “frequency hopping,” in which sensors and bases communicate through randomly alternating frequencies—in this case, the 900 MHz range. Frequency hopping is a common industrial practice that makes it nearly impossible for outsiders to tap into a frequency and steal data, and it reduces the likelihood that interference upon any given frequency will block transmission. The wireless community is currently engaged in debate over what frequencies are optimal for the transmission of radio frequency data in industrial applications, and whether or not clearer standards are required.

Can you hear me now?

To date, transmission at Roche has been clear and uninterrupted, Mills claims, even for sensors located down long corridors or around corners from their bases. “Even in the warehouse, with all the metal shelving, it still seems to be fine,” he says.

Another issue was making sure that the system would work without interruption, such as might occur during a power outage. The Honeywell sensors are each equipped with standard 3.6-Volt lithium batteries, ensuring that they’ll work even when the power grid is down.

To guarantee information redundancy and constant uptime for the system, the base radios were connected by coaxial cables to Kingfisher remote transmission units (RTUs), manufactured by RTUnet, an Australian firm specializing in supervisory control and data acquisition (SCADA) applications. When power is restored following a plant shutdown or rare outage, the RTUs send a history backfill to the corporate network.

The RTUs pass data to Experion along Roche’s local area network (LAN). “Usually the process control systems have their own LAN,” says John Atwell, Honeywell senior account manager. “But since there are buildings all over this large campus, we used their existing LAN that connects the entire site.” Having to install another network to connect these buildings, with more coming on in the future, would have been cost-prohibitive.

The equipment was installed quickly, but validation took much longer. Because the system was on the Roche LAN, “we needed Roche’s approval and involvement, and had to validate the computer system first,” says Atwell. “Then we had to show that the software, the controllers, sensors and the whole system was operating like it’s supposed to.” Still, the implementation and validation process, which began in August of 2004, was completed by the end of the year.

Up and running

The system now essentially runs itself. The base radios send data each minute, as programmed by the RTUs’ ladder logic. The Honeywell base radios can handle up to 50 floating point values (whether temperature, humidity or other values), which conforms to Distributed Network Protocol (DNP) standards. “We’re looking at actual values and taking them into Experion every five minutes,” says Mills, one of four technical experts from Honeywell working on-site for Roche in Indianapolis.

There are plenty of “behind-the-scenes” applications that operators can access and manipulate, Upwards adds. The system monitors not just temperature and humidity, but also sensor battery life. Should temperatures move out-of-spec, or should a battery run low, a pop-up alert appears on control monitors logged into Experion. Whenever an alarm situation arises, the RTU signals off-site Honeywell security, who notify key Roche personnel on a designated call list.

The wireless system has been up and running less for than a year, but Upwards says the benefits are clear. First of all, there are no more paper charts to be managed, freeing up employees to attend to more pressing concerns.

Another benefit is that any operator can easily access critical warehouse data, and do it from anywhere via a PC. An Experion E-Server linked to the main server helps ensure that information is continuously available in managers’ and supervisors’ offices, and in any remote location.

The system’s web functionality paid off when a warehouse experienced a heating system malfunction over the New Years holiday last year. Operators monitored key parameters from home. “We were able to maintain data, and the quality folks went back in after and were able to demonstrate with peace of mind that none of products fell out of required storage temperatures,” Mills says.

Even when pressed, Upwards says there have been no problems with the wireless system. Roche has tweaked the Experion system to adapt to the wireless implementation, he says, but has not had to touch the sensors. “We know that we have a system that complies with regulatory requirements and provides us with the ability to generate data when we need to,” says Upwards. “The people on our quality team find this a very useful tool.”

If anything, Roche’s wireless monitoring has proven so dependable that “it’s now taken for granted,” Upwards says. “The novelty has worn off.”