How suppliers are creating better machine control systems
Today's machines communicate with rest of your plant equipment.
Is your aging packaging line an island of automation? Do you know its OEE score? When something goes wrong, how long does it take to find the problem, fix it and get it running again? Do you know how many products you ran through it today and how many rejects you had?
- PLC or PAC: Does it really matter what it’s called?
- PackML evolution
- PackML gets a little help from OPC UA
- Machine safety: Hardwired E-stop not dead yet
- Remote monitoring vs. security
- Sidebar: Weihenstephan Standards define communications between machines and MES
- Sidebar: Machine HMI design issues: Engineer, artist, linguist?
Today, machine builders are creating hardware and software that communicate with the rest of your plant equipment plus your shop floor MES and ERP systems. When something breaks, chances are the machine can tell you exactly where the problem is and how to fix it. If that’s not possible, your machine builder can log onto the machine and find the fault within minutes—no travel time and no expenses. You’re back up and running. Back at headquarters, senior staff has been following the event, and immediately knows the impact on production and can adjust accordingly. Futuristic? Not really—it’s available right now.
FE talked with machine builders, system integrators (SIs) and component suppliers to get a handle on what food and beverage processors can expect with the latest and future generations of machine controls. It turns out that several improvements in technology have been occurring at every level, including faster processors, cheaper and more dense memory and industry-standard machine programming and communications protocols. With these improvements, machine safety has been evolving from hardwired switches and separate safety controllers to integrated safety systems. And cybersecurity is as good as your bank’s.
Dating back to 1999 and founded and developed by the Technical University of Munich (TUM), Chair of Food Packaging Technology, the Weihenstephan Standards (WS) are popular in the beverage filling & packaging industry (WS Pack), and increasingly in the food processing industry (WS Food), and provides the link between the production management level and the machine level. WS consists of standardized data using WS production data and the WS communication protocol (WS-proprietary commands used with the TCP/IP protocol). Additionally, WS supports the ISA TR88.00.02’s (OMAC PackML) mode manager and state model.
Per the Weihenstephan Standards website: “The Weihenstephan Standards (WS) define a universal communication interface for the connecting machines to higher ranking data acquisition systems or MES (Manufacturing Execution systems). They also define the data which must be provided for acquisition. Data points and contents were defined for individual industrial sectors. Up to now libraries for bottling and packaging plants (WS Pack) and machines for food processing (WS Food) have been realized.”
Communication via a plug-and-play principle is made possible by automated parameterization via a device description file. Moreover, the Weihenstephan Standards give recommendations for the data evaluation (e.g., traceability, calculation of efficiency identification numbers, technical reporting) and for the approval and the safe operation of MES implementations.
Source: Siemens Energy.
The heart of any machine is its controller(s), which used to be the PLC. In many respects, the PLC has evolved, and the result is a single device, the programmable automation controller (PAC), which not only handles standard logic (off/on) functions, but also can provide motion/position control, robotics supervision and process control while connecting to Ethernet networks and real-time sensor/actuator networks. These capabilities are provided within an architecture, often resembling a PC, and either exist on the “motherboard” itself or through the use of plug-in cards.
“This convergence of automation and IT technologies provides all the functionality needed from a PLC, while adding a wealth of other features in one programming environment,” says Bob Trask, Beckhoff Automation senior systems architect. These features include integrated motion control, kinematics, condition monitoring, programmable safety and HMI.
“In the near future, we see vision and predictive maintenance functionality being implemented,” Trask adds. “[Our] TwinCAT3 automation software adds programming in Visual Studio, maximized performance for multi-core PC-based controllers and IoT [Internet of Things] solutions for easy-to-implement connectivity to the cloud.” The tools are already there, and Beckhoff is working hard to implement these IoT tools in such a way that the user does not need to be an IT expert.
Has the PLC given way to the PAC? While there are applications that are better suited to either the PLC or PAC, demand for the PLC has not wavered nor has the technology been forsaken, says Bill Dehner, AutomationDirect application engineer. “In fact, a better question to ask would be: Has the PAC given life to the PLC? To that, I’d say absolutely. Many of the features desired with a PAC are now being incorporated into the industry-proven PLC. Advanced PLCs today have bigger user memories, more communication, more data storage, more integration, more remote accessibility, and are more reliable than ever before.”
“PAC features are permeating the PLC world,” says Don Pham, IDEC product manager. “For example, even micro PLCs now include features that were only found in PACs as recently as a few years ago.” IDEC’s MicroSmart FC6A PLC provides PAC power with fast programming speeds, high-capacity programming and data memory—and an ability to handle up to 126 analog I/O. IoT capability is provided with custom web pages that can be configured for remote monitoring and control.
“One solution for easier integration and decreased time to market is a single, scalable control platform that supports the requirements of complex, batch manufacturing processes and high-speed packaging equipment,” says John Dart, Rockwell Automation senior industry consultant. “Manufacturers should look for machine controls that can be applied across a wide range of equipment types and complexity, and integrate across a plant-wide network. This scalability and consistency can help manufacturers increase productivity and reduce ongoing operating and maintenance costs.” Rockwell’s iTRAK system controls, for example, provide mechatronic solutions to packaging systems that allow for flexibility and independent control of multiple movers on straight and curved paths.
“Siemens controllers met all the requirements of the PAC long before the PAC name was created,” says Tim Parmer, factory automation - marketing, Siemens Industry. “Therefore, we have chosen to continue to refer to our hardware/software components as ‘controllers.’”
The SIMATIC range of controllers comprises basic, advanced, distributed and software controllers, offering scalability and integration of their functions. # SEW-Eurodrive’s controls portfolio contains PACs, which are called “MoviPLCs,” says Rainer Neufeld, electronics manager. These PACs are available in different performance levels.
“We combine optimally scalable controller hardware with easily programmable motion control software. Our continuous control program covers extensive motion functions: from single-axis positioning and electronic cams to robotics,” adds Neufeld.
Whatever you call it, the move to open architecture systems is on, and machine builders have enjoyed the benefits of a wide range of controls.
“We use open architecture software, such as Allen-Bradley, to allow for easy integration with other line components while giving plant technicians the ability to support and own their system versus ‘black box’ systems,” says Greg Jacob, general manager at Allpax Products, maker of retorts. However, he adds, PLC systems are still the preference, primarily due to plant history and support comfort level.
Polytron, a member of the Control System Integrators Association (CSIA), provides hardware and software as part of a turnkey system, though it’s not a controls product distributor, says Scott Richards, senior project manager.
“We work with many of the major automation platforms, including Rockwell Automation, Bedrock Automation, Wonderware, GE Proficy/iFIX, Siemens, Omron and others. Most PLCs would now be referred to as PACs due to their increased capabilities and features.”
Bühler Aeroglide makes convective conveyor thermal processing equipment, e.g., dryers, ovens, roasters, impingement ovens or coolers, etc. According to Pei Li, senior electrical engineer, “We provide a range of machine control hardware options to control our equipment. This includes common PLC platforms, which interface to Windows-based industrial PCs. We also offer more traditional HMI/PLC solutions as necessary. In our machine control area, we have not seen a demand from our clients for PAC. Furthermore, we believe the PAC is more complex and not as robust as PLCs.”
For JLS Automation, builder of robotic-based picking solutions for primary and secondary packaging applications, advanced PLC control has made design simpler. President Craig Souser notes, “We are migrated to what I call a complete machine control—PLC/Motion/HMI all running on the same platform within the same program. Advancements in motion control have made us comfortable in elimination of a standalone robot control system.”
HMI graphic design is really an art form. To make a good HMI, one needs to think about the true user of the machine, the operator, and how he or she interacts with that machine every day of its life.
First, engineers program the machine. They know every technical nuance in the machine and have intricate knowledge of how the machine works. So the engineer often creates an HMI for himself and not the machine’s operator. The result is a lot of buttons and technical jargon that make perfect sense to the engineer, but go way over the operator’s head.
Second, most engineers are not artists. There is an entirely different set of skills needed to understand graphics, layout, color schemes—even the type of button that should be used for a certain action. Most engineers will use whatever the HMI software’s defaults are for a button or a color because that is the easiest and fastest way to complete the project. Engineers are very reliant on the HMI software vendor. If that software is not well designed, or it’s difficult to use, the programming effort may end with a sub-par HMI. The result—HMIs that all look similar in appearance. As a test, visit PACK EXPO this year and see how many HMIs use a dark blue button with white text.
Third, there is a matter of time and cost. I can say first hand, that I can easily spend more time working on an HMI than I will in writing the PLC program. If an engineer wants to make nice graphics, he or she should be prepared to spend a lot of time working in a graphics program tweaking icons, scaling graphics and picking colors that work well for a specific machine. I also believe that every error of a machine should be brought out to the HMI with enough information for the end-user’s team to be able to fix the machine. One of our goals at Axon is to never force someone to access code because they cannot figure out a problem with help from the HMI.
Finally, using multiple languages in an HMI can be very challenging. As the language changes (say, from English to Spanish), the text size and length vary and cause readability issues. Typically, an engineer doesn’t have the benefit of knowing abbreviations in a foreign language if he isn’t fluent in it. So, during the course of the design project, an engineer will go back and forth between languages for every screen, making sure everything fits and works. At Axon, we work with a translation company that specializes in machine translation. This is important because a lot of words, like “HOLD” for example, could mean to carry something or to pause the machine. Working with a translator that understands these differences and nuances helps to ensure language translation makes sense to the end user.
—Christopher Thomas, Axon Corp.
Today, it’s all about communications and getting important operational data to those who need it. “It’s hard to go a day without hearing the words, Internet of Things or Industry 4.0,” says Christopher Thomas, director of controls technology at Axon Corp., a division of ProMach. Axon builds shrink and stretch sleeve packaging machines. “At the heart of these initiatives is the desire to access the wealth of data that is available in PLC- and PC-based machines and turn that data into actionable information,” adds Thomas. Lately, the use of Industrial Ethernet on the plant floor is bridging the gap between the operational technology (OT) and IT networks. Ethernet is available on almost any controls, which makes machine-to-machine and line control easier to implement. As this trend continues, Thomas says the ease to integrate machines from different technology vendors will increase.
“In the food and beverage industry, we expect to see less reliance on specifications naming a sole source vendor and instead more emphasis on specifying an interface [such as PackML] to connect machines,” adds Thomas. “We believe that this trend will drive innovation, better machine design and reduce cost for the end user.”
“We have seen a tremendous global growth with customers—OEMs, SIs, EUs [end users]—requiring ISA TR88.00.02 [OMAC PackML]-based solutions,” says Mike Pieper, industry manager - packaging, Siemens Industry. “This is due to the demand of global EUs [i.e., Procter & Gamble, Unilever, Nestlé, Arla Foods, etc.] requiring operational consistency between all OEM machinery [consistent programming modes and states, common naming of KPI tags] and higher-level systems [line overview, OEE, MES, etc.] with OEMs looking to harmonize their various machines, reduce engineering cost, leverage reusable and modular code and minimize commissioning.”
“Forward-looking machine and equipment builders see their products lasting 10 or 20 years,” says Richard Clark, InduSoft Wonderware Schneider-Electric application and process engineer. “These builders are actively pursuing PackML as a machine/process standard so their machines can interface and integrate into larger process environments as the customer’s production grows.” What are the alternatives for not pursuing PackML? Clark says either manually modifying and integrating the old, non-standard equipment into the larger automated production process or obsolescing the old equipment.
“PackML can mitigate complexity and establish standards-based machine operation,” says Beckhoff’s Trask. “A benefit of PackML is the PackML state machine, which defines standard modes of operation within the manufacturing process. The PackML state machine, when properly implemented, provides a common look and feel to the basic operation of a machine,” adds Trask. “This is a proven benefit to the OEM and the end user. What is the machine doing? Why is it in this state? The OEM does not have to create this [code] from scratch, and the end user does not have to figure out what the OEM has programmed.”
“In the four years that I have been working with PackML, I personally have seen a continuous growth and interest in PackML on the part of machine OEMs and end users,” says Thomas. One drawback is the current lack of an implementation guide to help those interested in PackML to get started on a project and to know what the main deliverables should be for a PackML machine. Fortunately, there is a guide in the works from the OMAC group, which got its start with automation standards in 1994.
“PackML is a terrific development,” says Mike Grinager, VP of technology for Brenton Engineering, a Pro Mach business. Brenton makes end-of-line packaging equipment such as cartoners, case packers, palletizers, etc. “However, it is a development that will take its own time and path through the packaging industry, and it will evolve.” There will not be, strictly speaking, only one PackML. For example, a number of Brenton’s Fortune 100 customers have their own internal versions of PackML. These versions could be described as dialects of PackML, which are optimized for these large companies’ environments.
“PackML has a number of positive attributes for OEMs in terms of lowering engineering overhead and allowing the OEM to be more productive,” adds Grinager. “Customers may not even be aware when they receive a machine [where the] PackML standard was utilized.” While PackML is not a monolithic development soon to be on everyone’s shop floor, it is a powerful tool to be used when and where it is most appropriate.
“While PackML provides a common look and feel to a machine or production process, getting this information out to the decision-makers and plant personnel requires a secure, vendor- and OS-independent transport mechanism such as OPC UA [Unified Architecture],” says Beckhoff’s Trask. OPC UA, as a transport mechanism on top of TCP/IP, moves key data to decision-makers and plant personnel.
“OPC UA offers built-in security and data encryption, and is ideal for exchanging data both horizontally with other machines on the floor and vertically into the cloud for access anywhere in the world,” adds Trask. “This adds valuable and tangible benefits for concepts such as ‘Smart Factory’ and ‘Industry 4.0.’”
The biggest challenge today with PackML is the lack of a standard communication protocol defined to allow communications with a machine no matter what control system is being used, says Axon’s Thomas. While a machine has an Ethernet port, this doesn’t guarantee any level of compatibility. Most major technology vendors have their own specific protocol, which typically doesn’t cross over to other vendors. This is where a universal protocol like OPC UA is needed.
“We are watching closely the development of OPC UA in the industry and believe OPC UA will be the great equalizer for manufacturers as it addresses so many pressing needs and is not specific to any vendor,” adds Thomas.
Travis Cox, co-director of sales engineering at Inductive Automation (provider of Ignition software), sees the interoperability issues with equipment and software as a really hot topic of concern.
“If the device is proprietary and requires specific software for programming or visualization, it will become an isolated silo of data. Devices should use open standards, such as OPC UA or MQTT, which allow interoperability.”
MQTT (fka MQ Telemetry Transport) is an ISO standards-based, publish-subscribe system, which is a lightweight messaging protocol for use on top of the TCP/IP protocol stack. MQTT requires a message broker, which is responsible for distributing messages to clients requesting a specific message topic—e.g., a certain process temperature or reject info.
Machine safety is, of course, a big deal. No one wants a warning or fine from OSHA. It used to be that an E-stop switch was hardwired such that hitting it would stop a machine, or an interlock switch would stop a machine or immediate section of it when a door or panel was opened. It also used to be that a parallel controller or PLC known as a “safety PLC” would run in conjunction with the main process controller, being able to shut down the equipment when a process or machine was progressing towards dangerous limits. Today, E-stops and interlocks are moving away from hard wired power interrupters to safety-based software solutions that receive a signal from a sensor, switch or other computed value, then shutting down the correct apparatus. But now a safety PLC can potentially reside on the same rack, chassis or board. How safe are these changes? What is the design philosophy for safety-rated systems? Can operators be prevented from “cheating” the interlock system?
“The large manufacturers are now beginning to standardize to Category 3 safety requirements, which include a special ‘safety PLC’ to provide redundant back-up controls and emergency stop scenarios,” says Allpax’s Jacob. “In addition, fencing with OSHA-approved gate permissive controls for entry, light curtains and physical machine guarding continue to evolve in required specification scope documents.”
For systems where E-stops or interlocks are activated via a touchscreen, there’s a method to protect people from getting their hands into operating machinery, says Tim Donaldson, Progea North America sales manager. “Multi-touch with two buttons on a screen to [stop] it. This will ensure both hands are not inside the machine.”
“We design safety as an integral feature in all of our systems,” says Polytron’s Richards. “We also offer safety risk assessments and safety mitigation for existing equipment. A properly designed safety system will be very difficult for an operator to override; at a minimum, such bypasses would be documented and alarmed. Modern safety systems utilize software as well as redundant wiring. We make no distinction that software-based systems are somehow less safe. If that were the case, we would never use them.”
“Software-based solutions can actually [ensure a] higher level of safety as it’s more difficult to override if implemented properly,” says JLS Automation’s Souser. “Drive-based safety is much faster and more distributed so that makes for a safer solution.”
“Machine-based risk analysis and mitigation plans are critical to engineering safety,” says Doug Beloskur, automation manager at Bühler Aeroglide. “Based on our mitigation strategy, we can design safety systems to lower the risk of personnel injury and machinery damage. In mind of simplicity, we utilize hardwired interlocking for electrical means of risk mitigation. We make efforts to design out major hazards up front to eliminate the need for safety PLC systems.” Beloskur also says that providing as much safety-related information to operators as possible, which can be accomplished through audible and visual warnings, is extremely important. Operator training is an absolute necessity so the right safety decisions can be made to protect operators and machinery, and this also includes well placed safety labels on all equipment.
“Lastly, regarding software-based emergency stops,” continues Beloskur, “we do not believe this is reliable enough or yet acceptable by our customer standards.”
Remote access/monitoring would seem to be at odds with security, but if implemented properly, remotely viewing operations or equipment can bring dividends—both from production and maintenance (remote troubleshooting) standpoints. “Operations personnel want remote access because it means faster, easier problem resolution,” says Brenton’s Grinager. “The IT department typically does not want to grant remote access because so much in the plant is linked back to the MRP system. It is a big problem, and both sides have valid points.”
“Maintaining line efficiency is super critical for plants to hit their budgeted goals for line production,” says Allpax’s Jacob. “Monitoring machines to report efficiency and resolve downtime scenarios is very valuable. Line efficiency gains typically far outweigh monitoring costs and make ROI justification an easy decision.”
Some processors are still reluctant to allow monitoring and servicing remotely on their machines, but this has been slowly changing over the years, though it’s still an uphill battle for machine builders.
“It is our belief that most customers want the technology, but there is a lot of concern over security and the awareness of friction with the IT department anytime these requests are made,” says Axon’s Thomas. Axon offers a remote monitoring and service package called ProTech by Pro Mach with its machines, which allows troubleshooting without sending a technician to the site, incurring further costs. This gets customers back up and running faster.
“It is our hope that as the use of Industrial Ethernet grows, the IT and OT networks will begin to work much better together, and this will open the door for remote monitoring and access,” says Thomas.
Today, OEMs have the technology to make remote monitoring safe. “We depend on the security of the plant network to safeguard individual machinery,” says Bühler’s Pei Li. “However, we understand the need for remote access of our machines from time to time. In these cases, we utilize VPN connections to gain access.” For further security, this OEM’s equipment offers customizable user-level security to suit each client’s needs.
JLS Automation takes monitoring beyond just the typical equipment sensor data. “We equip all of our machines with remote access and are offering cameras to monitor lines. We work with the end customer to help them troubleshoot, and in more and more cases, this is the operator and not maintenance. We are looking to embed videos in our HMI to facilitate the training of new operators to a machine.”
While you might think security issues only concern themselves with hackers breaking in and destroying equipment, probably the more relevant concern is leakage of intellectual property—and not necessarily through hacks. SEW’s Neufeld explains: “There is still an acceptance problem when it comes to letting other companies supervise production equipment. On one hand, everyone wants the quick support and in-time diagnosis; on the other hand, no one wants fact(s) such as production speed or quality to be known outside the company. SEW understands this dilemma, and our answer has been to offer diagnosis that can be used remotely—but only if the operator allows it.”
Finally, at the plant level, a tiered password structure maintains security. At the network level, the OEM and the processor’s IT department need to coordinate so that both groups understand the needs and requirements of the other, says Grinager. Virtual private networks (VPNs) linking only the machine, or an island of machines, back to the OEM is the current state of the art. Are VPNs secure? “Some VPN hardware and software combinations mirror the same high level of security one finds in the banking industry,” says Grinager.