Machine Control Integration Produces Savings

Plants are relying on new generations of more fully integrated control technology to run smaller, faster and more efficient machines.

Opto 22 first implemented its machine and control technology on its own line. At its Temecula, Calif., factory, this automation supplier produces its G4 modules—single-point input/output (I/O) modules used mainly for applications involving the sending and receiving of digital signals. To ensure that the modules will live up to their lifetime guarantee, the modules are put through the G4 handler for testing. The test includes current load tests as well as inductive, capacitive and resistance tests.

The handler moves large trays of 50 modules back and forth, and left and right while the machine puts each module through several tests.  The company recently rebuilt its handler for greater movement accuracy and smaller size.

The company also wanted to consolidate all I/O functions into a single platform. “You don’t need multiple devices or components to handle typical digital points—like a machine’s limit switches—and then another system for recording analog readings—like machine temperatures—and then a third system to execute the machine’s motion control,” says Ron Schmidt, the Opto22 manufacturing engineer who built the handler. “Now, all the interfacing of sensors and components is performed by a single system, and all functions are defined using a single development environment.”

Welcome to the new world of motion control, where machine information and control are consolidated. “Everyone wants something simpler. So it’s an advantage having motion control as part of your normal programming environment,” says Schmidt. “You want to keep everything under one umbrella.”

The new handler is also more efficient, easier to use, and takes up less space than previous methods used by Opto 22, while all the controls are also more accessible. “Before, we had the old brick system, which had the controller and different brains—we had six racks with six different brains,” says Schmidt. “We got rid of the controller and put it in one brain. It shrunk the machine big time. We’re talking less than a quarter of the space. There’s really big energy savings there.”

The data link to the machine also supplies information from the machine to Opto 22’s enterprise system. “We can see the pass/fail rate, we can track throughput and we can keep test time to a minimum,” says Schmidt.

Motion control is benefiting from integration with control technology. The goal is to bring motion data into the control system, so machines are easier to program. The result is to ability to use smaller machines, smaller and more efficient motors, and the ability to change machine configuration on the fly. Plant operators are also deploying simulation technology to work out the bugs and make adjustments to the machines that allow for quick changes from product to product.

One of the advantages of combining motion control with the overall control systems is that operators can make machine adjustments without deep knowledge of motion programming. “Demanding motion-control applications that require high-performance precision can be fully tested out with their phase compensation feature estimated, so the programmer does not need special knowledge of the system components to do it,” says Bill Faber, senior manager, application engineering, Motion Control Division, at supplier Yaskawa Electric America Inc., Waukegan, Ill.

Using integrated automation to run machines also allows machines to do more. Grenzebach Corp., in Newnan, Ga., builds high-speed stackers, including a machine that stacks glass on a float glass line. Float-glass stackers have long been plagued by slow throughput and displacement that causes breakage. Yet it’s an important production stage for machine operation, as this is the most labor-intensive part of glass production. “Our customers have been demanding a better solution for stacking the many different glass sizes that they manufacture,” says Gerald Haas, technical director at Grenzebach.

Grenzebach engineers went to work with Alphareta, Ga.-based vendor Siemens Industry Inc. to produce a new line of glass handling equipment that features integrated control systems to provide a fully automated stacker. Every function of the cold-end line is being integrated into one control automation platform—including take-over of the glass from the lehr (a kiln used for glass annealing), cutting the glass ribbon into sheets of optimum size, glass snapping, rejection of faulty glass sheets, sorting according to size, and stacking into glass racks with robotics.

Throughput booster

By bringing these functions into one complete and integrated control system, Grenzebach has been able to reduce production costs and increase throughput. With the integration of the stacker into the control system, the new stacker provides transparency at all levels and reduced interfacing requirements. It also provides interoperability of the controller, human-machine interface (HMI) and drives with the process control system, reducing the complexity of the plant’s automation.

The net result is lower engineering costs, higher machine performance and the elimination of time-critical interfaces between individual components. It also means simple, uniform and transparent programming and diagnostics for the entire machine with a single tool. The greater control over the machine also provides enhanced safety and employee productivity.

As machines come under integrated control, they also require less space. “Physical size reductions are around 15 percent to 25 percent with each product version release,” says Yaskawa’s Faber. “The motor frame size reduction came from the high level of integration between the controller and servo. This evolved as a response to customer needs for one-stop-shopping of motion technology.” He notes that the integration also provides improved safety, start-up ease and improved time-to-market requirements.

Once the machine control is integrated into the overall control system, a manufacturing execution system (MES) system can be used to configure machine operation. “As an MES provider, we also have to provide machine control solutions,” says Torsten Werneke, chief executive officer of Germany-based Itemic. “The MES system has to have a high degree of configurability so you can change the product and change the complete manufacturing line.” Having machine control integrated with MES also lets plant operators map the entire production line and transfer it—with all its efficiencies—to another plant.

Simulating performance

Simulation is also being incorporated into machine control for greater precision and also to allow engineers a simpler programming environment. The simulation has moved beyond prototype testing and into overall production testing. “Simulation is not just computer simulation to build that first prototype,” says Todd Walter, senior product manager for industrial and embedded at National Instruments Corp. (NI), the Austin, Texas-based test and controls vendor. “It takes the algorithms and gets a prototype up and moving in production.”

The integration of the motion control with overall system control also allows the control operator to run simulated tests and work out the bugs before engaging the machine. “Some mechatronic systems require precise motion or machine-control sequences to insure expensive equipment is not damaged from a mis-applied move profile,” says Yaskawa’s Faber. “To prevent unintended crashes, motion-control vendors provide technology to run simulated motion in the control system. This allows the programmer to initiate move sequences from the controller to the servo amplifier through the network without even having a motor attached. The servo amplifier simply feeds back the commanded position as the simulated actual position.”

Using simulation, control engineers can also generate more complex motion profiles. “Simulation software enables the machine OEM (original equipment manufacturer) to develop and test PLC (programmable logic controller) and motion systems at the desk,” says Karl Rapp, segment manager at supplier Bosch Rexroth Corp., in Hoffman Estates, Ill. “The OEM and end-user can verify production cycle times prior to building the machine or production line.”

Reducing power consumption is another goal that drives the integration of machine control with the overall control system. “A lot of the power consumed is used to spin motors. With more motor control, you can design the system to run more efficiently,” says NI's Walter.

As well as controlling the motor, a control system integrated with machine control can help operators determine the most efficient motor for the system. “They’re bringing motor sizing to another level by looking at energy efficiency, heat and volumetric issues,” says Sal Spada, research director, ARC Advisory Group Inc., Dedham, Mass. “They’re completely automating it, so motor selectors are going through a wide range of motor selection.”

With greater technology connecting the machine to control, plant operators are bringing down costs in engineering time as well as energy. The integration also allows for a greater number of sensors that can alert operators to problems before the machine breaks down or slows the line. The machines can also be fine-tuned for improved speed and energy efficiency.

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