Monitor and Control on the Move: The Next Evolution in Factory Automation

For discreet and process manufacturers alike, the production line is the heart of the business. And at the heart of the production line is your automation system — the Programmable Logic Controllers (PLCs) — the ‘brains’ that control the production machinery. All day long, operators and supervisors on the manufacturing floor are in motion. Operators move back and forth to a desktop computer that is located in or near their station to interact with your automation system, entering and accessing data— from inspection information and alarm codes to performance indicators and maintenance schedules. And your supervisors leave the production floor to return to the office to access email, ERP and other business applications to make adjustments to shop floor orders (such as alternate routing or component materials) and to maximize human and equipment resources.

But with mobile technology in hand, operators and supervisors no longer need to leave the production line to perform business tasks. Instead, information can be delivered to the point of work — where and when decisions are made that will impact production, quality and safety. This white paper explores the logistics and benefits associated with extending mobility to the factory floor – and how mobility can help you leverage and enhance your investment in the factory automation system.

The challenge: Limitations of fixed manufacturing automation systems At the heart of manufacturing operations are the Programmable Logic Controllers (PLCs) that control the many functions of production-related machinery on the factory floor. The PLCs form the foundation of the manufacturing automation system. Layered on top of the PLCs is the SCADA system, the ‘control room’ that enables control of the machinery and recording of the vast amount of production related data. The ‘control panel’ into the SCADA system is via a Human Machine Interface (HMI) application, such as the Manufacturing Execution System (MES).

Together, the PLCs, SCADA system and HMI applications form the lifeblood of the manufacturing operation, providing the data and control over the manufacturing process required to protect throughput, quality and profitability. Through this system, the manufacturing enterprise can:

  • Determine if machines are optimized according to Key Performance Indicators (KPIs)
  • Respond to exceptions that require immediate action to protect against the manufacture of unacceptable product
  • Guard against unplanned downtime
  • Ensure safe operations

And it is this system that houses the critical production-related, real-time and historical data.

Today, operators and supervisors monitor, control and access the information from the real-time PLCs on a desktop PC, imposing a series of restrictions as a result of this architecture:

Footprint Additional physical space must be available to accommodate desktop PC stations on the manufacturing floor — pricey real estate that could often be much better utilized.

Flexibility In order to remain competitive, today’s manufacturing environment must operate in a highly flexible manner. As the demand for customized products increases, so does the need for maketo- order. The need to expand product offerings to meet customer requirements often means the production of multiple SKUs on a single production line — translating into rapid change-overs. In addition, production lines must be reconfigured regularly to accommodate evolving product lines or new regulatory requirements. When inflexible wired workstations are installed, these changes can be very costly, impacting the overall agility of the business — and the ability to meet changing customer and government-related demands.

Productivity Whether businesses choose to install one PC workstation for each piece of manufacturing equipment, or whether a single workstation serving a number of pieces of equipment is installed to conserve space on the manufacturing floor, operators are required to turn away from the manufacturing process to:

  • Enter information such as: inspection data on the equipment or product; classification of an event or alarm code and transactional information, such as the operator id, order number, raw material lot ids, order start and stop commands
  • Obtain information such as: performance indicators, for example, to ensure tolerances are within guidelines; real time event and alarms; historical information to analyze performance; and crucial maintenance information to help protect machine uptime

Quality control vulnerability When a PC is the bridge between the PLC and the operator, the operator’s input of critical operational information may be subject to errors or delays.

The solution: Monitor and control on the move In the manufacturing world, every second counts. If operators are required to turn away from a process for even a few seconds, a critical event could occur at that machine that might not be noted in time to prevent the manufacture of defective product. But when you move from a wired to wireless automation system, you can put the power of PLC access in the literal palm of your operators’ and supervisors’ hands via handheld mobile computers. Now, the mobile computer replaces the desktop PC as the information bridge between the machine real-world network and your transactional business systems, such as Enterprise Resource Planning (ERP), MES or EAM (Enterprise Asset Management). As a result, your operators are now closer to real time, closer to your machines, and closer to the product that is being manufactured — increasing control over the manufacturing process and overall profitability.

In addition to direct real-time automation system access, the same mobile devices can also help automate and error proof data entry through the ability to rapidly scan a standard UPC bar code, DPM (Direct Part Mark) or RFID (Radio Frequency Identification) tag.

The benefits of enabling mobile access to the automation system Mobility is the next evolution in manufacturing automation, the next logical step in utilizing today’s technology to connect plant operators and supervisors to information. When you choose to mobilize your automation system, the many benefits include:

Increased productivity — and staff capacity

When the PLC system is mobilized, operators no longer need to waste time traveling to and from the PC workstation to enter and obtain critical data. In addition, automated data capture capabilities such as bar code reading eliminate non-value added manual keying in of data. As a result, workers are more productive, and can spend more time actively monitoring the machines for which they are responsible.

A recent 2007 survey documents the productivity impact associated with mobilizing task-related applications in the manufacturing enterprise: nearly one-third of the manufacturing workers surveyed reported a gain of 50 minutes per day, directly attributable to the mobilization of organizational processes.

In addition, mobility combines with the productivity increase to pave the way for staff to act as true work-cell operators with responsibility for multiple machines. The manufacturer no longer needs to observe a 1:1 ratio of people to machines to ensure maximum quality control. Now, less staff is capable of running the manufacturing floor — with increased control over the machines.

Improves lean manufacturing score Lean manufacturing is a crucial manufacturing initiative designed to maximize profitability while ensuring consistent high quality of product. The elimination of time wasted walking to workstations and manually entering data can boost the impact of the company’s lean manufacturing initiatives.

Significant increase in data accuracy The machine operator is responsible for capturing a wide variety of information, such as the order number, the machine number, the employee number, the quantity of units that arrived and more. If data entry is manual —information is either entered directly into the computer, or onto a form via paper and pen first and then entered into the computer — the opportunity for errors in the data entry process is high. Mobile devices offer an alternative means of data capture. The ability to scan a bar code or read an RFID tag, or DPM enables the automatic capture of accurate data. Now, operators can simply scan:

  • A DPM to capture the identity of the machine
  • A bar code on the company ID badge to capture operator identity
  • An RFID tag for the raw materials or subcomponents to automatically document and verify accuracy of materials utilized

Now, the opportunity for many costly data entry errors is virtually eliminated. For example, if the wrong material was introduced into the process but inadvertently entered as the right material, the end result could be a recall — a very costly event. Washington State University estimates the average cost of a recall at just over half a million dollars. And in the pharmaceutical and food & beverage industries, a single Class 1 recall event can reduce shareholder value by as much as 1.5 to 3 percent.

Inaccurate entry of an order number can result in an unnecessary waste of production time and raw materials. And if a data entry error credited a machine downtime event as a raw material shortage instead of the actual overheating of a bearing, lack of visibility into the need for emergency maintenance on the machine could result in a shutdown of the production line — an event that can easily cost tens to hundreds of thousands of dollars.

Improve reaction time A mobile real-time data window provides the operational visibility required to improve reaction time to better protect assets (the manufacturing equipment) and the product that is being manufactured. The ability to ensure that maintenance is scheduled on a timely basis to address machine issues enables the identification and resolution of issues before they have a chance to threaten performance — or uptime. And the ability to more tightly monitor KPIs enables a more rapid response to any alarms — improving quality control and product saleability.

Ensure accurate inventories and job costing The improved integrity of data and the velocity in which data is available greatly assists the manufacturing enterprise in improving the accuracy of inventories as well as job costing. The real-time inventory can support initiatives that can dramatically reduce capital expenditures, such as Vendor Managed Inventory (VMI) or just-in-time inventory that can substantially reduce stocking levels. And more accurate job costing prevents under or overpricing of product — scenarios that can either affect the ability to compete or profitability.

Reduce costs With mobile PLC access, the heavy capital expense associated with the purchase, design and buildout of the PC workstations is eliminated. This will typically save a mid-sized manufacturing facility $500,000 to $750,000, while a large manufacturing facility with 500 stations could save in excess of $5 million.4

Improves supervisor productivity Mobilizing the automation system also improves supervisory capabilities. Supervisors now have all the information and tools they need right at their fingertips throughout the work day — from PLC, SCADA and MES data to applications such as email and instant messaging. And the real-time data supports real-time event management, allowing supervisors to respond more quickly to issues that can affect quality or result in material shortages that could shut down the line or cause the late delivery of an order. Not only are supervisors more efficient — they are more effective, and able to proactively act to reduce costs and protect profitability.

How it works There are four methods of connecting a handheld mobile computer to your automation system — the option that is right for your manufacturing enterprise is dependent upon your existing infrastructure and budget:

Industrial Ethernet — the direct PLC connection: Designed for newer PLCs with Industrial Ethernet A direct connection to PLCs with industrial Ethernet is the most robust and preferred option available. Since all nodes, PCs, PLCs and mobile computers are connected to the main industrial Ethernet network, the mobile computer can easily access all PLC data via standard XML, APIs and client applications. All devices that need to access the PLC data must be equipped with an Ethernetbased driver, preferably OLE for Process Control (OPC)-compliant. This option is most compatible with large companies that have an existing IT infrastructure and strategy as well as PLCs with industrial Ethernet capabilities — otherwise the cost to upgrade to industrial Ethernet-based PLCs may be cost prohibitive.

HMI as a mobile bridge:

Designed for companies with a fairly sophisticated HMI server

In this scenario, an HMI client on the mobilecomputer connects directly to an HMI serverthat is in turn either: connected directly to aPLC; connected to the PLC via a client bridge; orconnected to the same network as the PLC.

Dedicated card in PLC rack:

Designed for companies with a compatiblePLC rack

This option enables companies to more fullyleverage an existing PLC rack. A special card isplaced in the PLC rack that enables the bridgingof data from the PLC to the network. The mobilecomputer can then access the PLC data via XML.This solution usually requires more advanced andmore expensive PLCs.

Wireless client bridge:

Designed for older PLCs

For companies with older PLC models or PLCswith only serial communications, an access pointor access port can act as a client bridge that canbe utilized to enable real-time PLC access from themobile device. The access point/port must haveeither an RS232 or USB serial connector, which isthen connected to the PLC’s serial port. The clientbridge then broadcasts the information in 802.11standard formats that are easily received by themobile devices. In order to interpret and utilize thedata, the handheld device must be equipped eitherwith a standard driver or client, or a small customapplication. This option is the least sophisticated, anddoes have several pitfalls. The primary disadvantageis that the client bridge adds another point of failureto the network, increasing rather than reducing ITvulnerability. In addition, this connection tends to beless secure than an organic Ethernet connection.

Summary

On the manufacturing floor, your operators are responsible for remaining with their machinery for the majority of the workday. These seemingly stationery workers may not be the first candidates considered for mobile applications in your enterprise due to the close confines in which they work throughout the day. But nowhere else in your operations can a span of time as small as a minute have so much impact on your profitability.

When an operator is required to turn away from an operation in process to interact with the desktop computer attached to your PLC system, a critical event may occur that can result in the manufacture of defective product. And whether that defect is caught prior to shipment or after product has been released to your customers, the cost of that error is high — from the hard cost of wasted inventory and man hours to the soft costs associated with late delivery of a shipment, the delivery of defective product, and reduced customer satisfaction levels. In addition, when your operational supervisors leave the production floor, utilization of machine and human resources can be reduced.

It is mobility that can connect your employees wherever they are most effective: operators can remain focused on processes and supervisors can remain on the production floor. And by removing the waste associated with operator travel time to and from the desktop computer-based PLC portal, you are able to further lean your manufacturing operations. The result is a sharper competitive edge and a healthier bottom line through:

  • Faster reaction times that protect revenue
  • Automation of processes that increases productivity and reduces errors
  • Reduced costs through tighter inventory management
  • Improved profitability through better job planning and costing

About Motorola Motorola’s rugged mobile computing products combine with advanced data collection capabilities and wireless networking to provide a unique opportunity for manufacturers to move HMI and machine monitoring and control to the actual point of activity. With Motorola, you can count on a real-time connection to your automation and HMI systems that will eliminate the need for operators to move back and forth to fixed stations to enter and access machine information, improving productivity, quality and control over the manufacturing process.

Motorola offers true end-to-end mobility solutions for manufacturers and more that include: a comprehensive portfolio of mobile devices with extensive wireless communications capabilities; a portfolio of private wide area and local area network infrastructure; a partner channel delivering best-in class applications; and a complete range of pre-and post-deployment services to help get and keep your mobile automation system solution running at peak performance every day of the year.

And as an industry leader, Motorola offers the proven expertise and technology you need to achieve maximum value and a fast return on investment — as well as first hand experience in the application of lean manufacturing principles. In fact, Motorola was awarded the coveted Shingo Prize in 2003, in recognition for achieving world-class manufacturing status through the application of lean manufacturing principles.

To find out how Motorola’s mobile automation solutions can help you achieve real-time PLC access in your manufacturing plant, please visit us on the web at www.symbol.com/manufacturing. For inquiries in North America, please call 1- 866-416-8593, or for international inquiries, access our global contact directory at www.symbol.com/contact