Discrete Manufacturing - Control Engineering

Learning Objectives

Control system upgrades are inevitable, but manufacturers can make the process easier.
Manufacturers should ask whether this upgrade will prevent obsolescence and improve overall system flexibility.
Picking the right communication protocol is also important.

Equipment and controls upgrades are an important, inevitable and often painful part of maintaining effective operations in any industry and especially in fulfillment and parcel applications. These upgrades are important in ensuring the highest performance, guaranteeing equipment can keep up with increasing demands. Controls upgrades also provide the latest operational effectiveness and functionality, ultimately protecting and extending equipment investments and even the technology itself through the Industrial Internet of Things (IIoT) for Industry 4.0 initiatives.

While controls upgrades are inevitable due to lifecycle considerations for electronics and processors, the pain associated with controls upgrades is not. Engineers can mitigate headaches with good planning and sound decision making and eliminate the rip-and-replace scenario that so many companies cringe at when deciding whether to extend the life of a piece of equipment.

Upgrading control platforms can protect against future obsolescence, increase system flexibility, enhance technology or meet budgetary or cost-of-ownership requirements. Courtesy: Beckhoff Automation

Explore four key questions when upgrading machine controls

When planning a controls upgrade, first consider goals for the upgraded system. Is the company trying to protect against future obsolescence, increase system flexibility, enhance technology or meet budgetary or cost-of-ownership requirements? Also consider available downtime for the controls upgrade. All of these aspects can play a key factor in choices about enhancing system characteristics and the overall solutions for the upgrade.

1. Will your control system upgrade protect against future obsolescence?

This comes first for an important reason. Considering the architecture of the control platform and even the history of a control supplier’s lifecycle can ensure control application won’t face another controls upgrade in just a few short years. The architecture of the control platform also plays a key factor in the flexibility of the system, which is important to ensure equipment can flexibly adapt to industry trends and changing consumer demands. When choosing a replacement control platform, companies should look for:

Ease of future replacement/upgrades of processors to eliminate the vicious cycle of re-engineering, added costs and future downtime associated with processor and system obsolescence
Scalability and portability of the control software for future extension of functions and support across the current and future controller portfolio to further eliminate engineering effort when a processor reaches end-of-life
Connectivity of local inputs/outputs (I/Os), reducing cost and labor associated with replacing local I/O and re-wiring all sensors when a processor reaches end-of-life
System openness that supports legacy protocols, which may be present in the current control solution, as well as support of many modern protocols required for both horizontal communication with other equipment and sensors, as well as vertical communication to support digitization and IIoT initiatives.

In general, identify all of the current control platform’s limitations. This includes the fieldbus as well as any control platform and fieldbus being considered for the upgrade. Any limitation can become a weak link in the chain of current and future systems, so carefully considering limitations is crucial to avoid costly mistakes.

When looking at a controller’s limits, consider performance, number of devices that can be connected to the controller or fieldbus, the topology supported by the fieldbus and the fieldbus and controller’s connectivity to other open protocols required for horizontal and vertical communication. Also consider local data acquisition (DAQ) capabilities, available RAM and even analytics if that fits into predictive maintenance goals.

2. Are you increasing control system flexibility?

When evaluating gains in control system flexibility, a key area to explore is distributed control capabilities versus non-distributed, or centralized, which is where fieldbus evaluation becomes even more critical. I don’t mean the distribution of control code via multiple programmable logic controllers (PLCs), but instead the distribution of I/Os, drives, scanners, cameras, robots and other devices in the control system. Careful evaluation of the fieldbus should eliminate distributed PLCs from consideration, which just bolsters fieldbus and PLC limits.

A distributed approach with a central integrated controller offers the highest amount of system flexibility and protection from obsolescence. However, if the current control system is hardwired back to the main control cabinet, the budget and tolerance for downtime to convert to a distributed approach should be evaluated.

A fully integrated system architecture provides optimal protection against obsolescence and protection of investments. The basis for such a flexible architecture should be the wide scalability of PLCs and industrial PCs (IPCs) ranging from micro-controllers to powerful many-core machine controllers with up to 40 cores. Look for vendors that ensure their controllers support a standard automation software platform that integrates all control system functions. This platform should be able to run on one powerful integrated machine controller, even on next-generation controllers, and support separating PLC tasks in separate cores of the powerful multi-core machine controllers.

Single-purpose “black box” controllers are no longer necessary for hosting separate functions of the control system, which create a circulating end-of-life cycle throughout the system. Instead, one powerful machine controller can synchronously execute all functions: PLC, motion control, human-machine interface (HMI), robotics, vision, safety, speech, measurement, analytics, machine learning (ML), condition monitoring and even mechatronic solutions such as linear transport and levitating planar motion technology. This all-in-one philosophy enhances the control system and eliminates the brutal re-engineering required by traditional control platforms.

With support for all open communication protocols, TwinCAT software establishes secure data transfer to the enterprise level or the cloud. Courtesy: Beckhoff Automation

3. Are you trying to enhance control system technology?

Companies make investments in new controls technology for many reasons. These include, but are not limited to:

Eliminating performance limitations
Adding integrated safety functions
Incorporating Industrie 4.0 concepts and predictive maintenance
Improving diagnostics for maximum uptime
Appending the system with robotics and vision systems
Improving the machine’s operator interface, such as extended HMI graphics and animations, tablet and mobile phone interface, cloud and web connectivity, etc.

Accomplishing these goals requires flexible controller hardware, but it also needs more open software and networking solutions. To achieve this connectivity, the automation software platform should support all open legacy and modern fieldbus protocols as well as all open vertical protocols for easy connection to enterprise systems, warehouse execution and warehouse control systems, and even cloud systems. OPC UA, MQTT, AMQP, HTTPS/REST, Real-time TCP and Modbus TCP are a few of the optional protocols the software should support. The same goes for industrial networking: The control platform should support all open fieldbuses, industrial Ethernet systems such as EtherCAT from Ethernet Technology Group, EtherNet/IP from ODVA and Profinet from PI North America and device-level networks also. This ensures easy integration into an existing system being upgraded or a new system in a modern facility.

The benefits of the integrated system approach go even further, in terms of flexibility and stability for technology enhancements.

Integrating industrial communications, safety, I/O

EtherCAT, when used as the basis for fieldbus communication, also can integrate all legacy and modern fieldbus protocols into the EtherCAT network. This improves the performance of the fieldbus.

EtherCAT also improves upon system flexibility with the growing importance of machine safety. Fail Safe over EtherCAT (FSoE), an international standard according to IEC 61784-3, enables e-stops, limit switches, safety mats and other safety devices to be wired into EtherCAT safety I/Os and communicated across the same Ethernet cable that connects with all other standard machine sensor and drive signals.

An integrated control architecture can use EtherCAT as the communication for all local and remote I/O racks instead of proprietary backplane protocols used across the industry. The use of the open EtherCAT communication for the backplane protocol reduces cost, improves performance, greatly increases diagnostics and extends the topology possibilities. Further, some vendors offer the same I/O hardware for both remote I/O racks as well as for the local PLC racks. This eliminates the rip, replace and re-wiring that is common with other control platforms when the local PLC I/O becomes obsolete as the PLC processor reaches end-of-life. In those other platforms that means a significant amount of re-wiring during a controls upgrade. As one final point, users should check that the vendor makes all firmware backwards compatible, so replacement of an I/O terminal requires no firmware upgrade in the controller, even if the I/O terminal supports a newer firmware than the one being replaced.

EtherCAT offers the optimal industrial Ethernet fieldbus for communication across mixed networks in brownfield applications. Courtesy: Beckhoff Automation

4. Are you trying to meet control system budgetary and ownership cost requirements?

A straightforward approach to the integrated control system architecture and EtherCAT helps ensure the system supports current and future machine requirements with system openness and protection from obsolescence. It also helps with the budget for the upgrade by eliminating many CPUs and switches. Expenses for software engineering tools, phone support and online training can factor heavily in cost of ownership associated with many controls platforms. However, it doesn’t have to be this way; some vendors offer these for free.

Drive technology selection also can aid in the upgrade of existing systems. Some vendors’ EtherCAT drives support the control of existing third-party motors, so motor replacements are not required in the controls upgrade, significantly reducing cost and upgrade time. These drives can also be effectively used to control varying types of motors, including servos or induction motors. And with FSoE safe motion functions integrated into the EtherCAT drive technology, further advances in machine safety are possible while reducing the significant cost of contactors, wiring and additional safety I/Os. Intuitive drive technology furthers the ease of an upgrade, reduces cost and required downtime, and helps modernize the machine’s safety functions.

So whether a company is planning a controls upgrade or considering a next-generation control platform, an integrated control architecture with EtherCAT provides significant advantages and protection from obsolescence.

With the flexible architecture and support for all legacy and modern protocols, a graduated migration of the field-installed systems and your new equipment is possible. This mitigates risk and advances the team’s learning through the evolution of the control system towards the complete benefits of a fully integrated platform.

Doug Schuchart, material handling and intralogistics manager, Beckhoff Automation LLC. Edited by Chris Vavra, web content manager, Control Engineering, CFE Media and Technology, [email protected].