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1 April 2002

Wireless Speeds Up Just in Time

Increased efficiency can save time, money.

By Ray Wright

Manufacturing operations of all sizes and sectors—from heavy to light industries and from process to flow plants—are under intense pressure to increase efficiency. Their frequent goal? Just-in-time (JIT) manufacturing, complete with high output and low production costs.

Most modern manufacturing plants make heavy use of a robust network infrastructure, and the dynamic and results-driven nature of manufacturing facilities places unique demands on their communications architectures.

To support JIT manufacturing, employees are constantly on the go, moving throughout the office, warehouse, and production areas. Yet they often need quick, convenient, and secure access to centrally housed information. At the same time, the manufacturing environment is continually changing, often requiring various adds, moves, and/or changes to production machines. Rewiring and reprogramming machines is frequently costly and time consuming. To ensure the highest level of productivity, network resources must be fast, flexible, and always available.

Today's IEEE 802.11 standard-based wireless Internet protocol (IP) technologies offer a high level of adaptability that can benefit the entire enterprise striving for manufacturing excellence. Wireless IP technologies can reduce costs, save time, and improve efficiencies when dealing with everyday supply and demand challenges.

Importantly, wireless can deliver the security, flexibility, and mobility that manufacturing operations require for JIT production needs. From the front office to the back office and from the shipping dock to the production floor, wireless technology helps manufacturers increase workflow, improve production yields, and solve problems more quickly.

WHERE WIRELESS WORKS

There are many areas where wireless networking can work in a manufacturing environment. Laptops, desktops, printers, scanners, terminals, and other handheld devices can all be equipped with wireless technology to connect manufacturing to the corporate infrastructure.

Wireless technology enables engineers and technicians to access technical drawings while roaming the production floor and also enables maintenance crews to quickly communicate with the central office for scheduling and emergency repairs.

An integrated wireless network on the production floor enables workers to use their time more efficiently and better manage supplies, inventory, and products as they move in and out of the factory.

It is not uncommon for manufacturing operations to maintain two separate networks: one for general business use and another for engineering operations. Standards-based wireless and networking technologies allow manufacturers to meet the needs of both user groups with one integrated network.

By deploying a standards-based integrated system and configuring it for the individual user needs of the business, manufacturers can simplify the complexity and lower the costs of network administration. A single integrated network would also free up information technology resources to work on other, more strategic initiatives.

Wireless vendors are now addressing early concerns over wireless security. Rapid key regeneration, 128-bit encryption, and policy-based management help ensure today's wireless installations are as secure as their wired counterparts, and the combination of wired and wireless access provides the flexibility manufacturing employees need. Management, engineers, and technicians access the information they need, wherever they are in the plant.

DOWNTIME REDUCED

When plant equipment is down, so is productivity. A wireless network helps technicians be more efficient and undertake changes, maintenance, and repairs more quickly. Technicians can access technical drawings while roaming the production floor, streamline communications with central office staff, and reach machine manufacturers online for programming or repair instructions, manuals, and online help.

Wireless also eliminates the need to maintain a PC near production machines, saving space and lowering costs.

Wireless networking is particularly suited to operations where manufacturers need to rearrange machines on a frequent basis or where the cost of reprogramming machines that are occasionally moved is prohibitive.

In many plants, network specialists are not readily available. When a line needs reconfiguring, many organizations contract with outside specialists to reconfigure the production network, including cabling and reprogramming. This can be both expensive and time consuming. The resulting downtime and loss of production capability may well justify, all by itself, investment in a wireless solution.

Using a wireless network allows manufacturers to relocate machines with no impact on the underlying network. This means no rewiring, no network reprogramming and no network debugging.

For environments where operations are continually making changes to accommodate JIT manufacturing, wireless adapters can be interfaced with production machines to provide a wireless connection to the network, reducing time and expense normally associated with moving them. By integrating wireless technology with connected production machines, staffers can quickly reconfigure the shop floor network without impacting the cabled network, simultaneously improving their ability to manage adds, moves, and changes and fixing previously nonnetworked production machines.

REAL-TIME INVENTORY CONTROL

Integrating wireless solutions with various mobile devices (bar-code scanners, personal digital assistants (PDAs), printers, and terminals) throughout the manufacturing environment is becoming critical to supporting JIT manufacturing. Today's technology can support everything from the nonnetworked production machines mentioned above to pick order processing with wireless bar-code scanners to placing shipments on trucks using forklifts with wireless terminals and printers to monitoring valves and pipelines with wireless cameras in process manufacturing plants.

For indoor applications, wireless access points and antennas are designed to provide coverage up to 300 feet, with buildingwide coverage achieved by deploying suitably placed multiple access points. Properly equipped employees have instant access to information when they need to process an order or pull inventory on the fly.

Typically, for warehouse and terminal deployments, laptops and PDAs with wireless cards will communicate through ceiling- or wall-mounted access points strategically located to provide the best coverage. In this way, wireless connectivity helps provide real-time inventory and production control by feeding production requirements directly to dispatching or ordering systems wirelessly connected to forklifts or truck drivers.

This eliminates several steps, such as printing orders and having drivers stop to pick up printouts, and helps make JIT manufacturing a more achievable goal.

LINKING MULTIPLE BUILDINGS

Outside, directional wireless antennas provide for point-to-point and multipoint configurations spanning distances up to several miles. With line-of-site connectivity, 802.11 wireless links provide high-speed connectivity among plant buildings on the same or nearby sites. By eliminating telecommunications costs and reducing installation costs associated with laying cable, manufacturers can achieve significant savings. Wireless technology allows manufacturers to bring all of a plant's facilities online, including buildings they did not network before. In addition, wireless links are frequently faster than affordable terrestrial links.

Typically, telephone companies install a T1 or digital subscriber line link for short distances. These come with a price tag of $200 per month or more and operate at 1.5 megabits per second (Mbps) or lower. Depending on distance, wireless links usually operate at 2 Mbps or higher. For companies with existing links, wireless can also be a backup link to maintain constant communications in case disaster strikes.

WIRELESS LIMITATIONS

Factory environments are not always highly conducive to wireless operation. Some waste management sites experience corrosive air quality that can be detrimental to all electronic equipment. Other plants may suffer significant electromagnetic interference.

For example, plasma arc welders generate magnetic impulses that may cause radio frequency (RF) concerns. Most production facilities have their share of RF issues caused by electric machinery, construction materials in the walls and ceilings, or nearby sources of interference from outside the plant.

Similarly, the success of vehicle-mounted wireless applications is determined in part by warehouse construction and vehicle speed (802.11 is not currently suited to high-speed vehicle applications). To be successful, all 802.11 wireless IP applications should begin with a thorough site survey undertaken by a trained and competent supplier.

The site survey should determine the optimal location of wireless access points to maximize signal propagation, connection speeds and coverage areas while minimizing the effects of RF interference.

Site size and number of users will also be factors in determining the viability of wireless networking. Wireless spectrum is a shared medium. For sites with a large number of wireless users who transmit high data volumes, a combination of flexible wireless access with fixed (wired) access points may be the most cost-effective approach.

INITIAL COSTS HIGHER

In general, wireless systems have slightly higher capital costs than their wired equivalents. However, lower installation costs in many plant environments, wide-area telecommunications savings, benefits of staff mobility, and lower production line configuration costs often make wireless a more cost-effective overall solution.

Additional benefits for manufacturers also include improved safety in hazardous material areas by reducing cables and ease of upgrading to higher speeds as 802.11-based wireless technology develops. Already, access points are available that support the existing 802.11b (11-Mbps) standard and the newer 802.11a (54-Mbps) standard. By changing the pocket-sized 802.11b wireless cards inserted into dual-mode access points for 802.11a cards, manufacturers can increase the speed and efficiency of their network by up to 500%.

Just-in-time manufacturing is something most manufacturers are reaching for. The wireless technology available today enables them to get there faster and prepare for higher levels of automation coming in the future. IT

Behind the byline

Ray Wright is vice president of industry marketing for Enterasys Networks, a worldwide provider of communications infrastructures exclusively tailored for enterprise-class customers.

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