How to Select the Best Machine Controller for Your Application

With the growing number of controller choices available to automation engineers, separating the chaff to find the best device for their particular application can be difficult when evaluating multiple platform types. Industrial PCs (IPCs), Programmable Logic Controllers (PLCs), and Programmable Automation Controllers (PACs) all perform essentially the same function: equipping machines with control and automation capabilities. However, one should always heed the “good, better, best” scale when evaluating machine controllers.

So how do engineers differentiate between these choices and make the correct decision for specific applications? When designing projects from scratch, it is best to begin with, this question: Will the application remain the same and never require an upgrade over the entire life of the machine? If so, then a lower-cost PLC or PAC may be an option.

Realistically, most companies will need to improve, upgrade and customize their applications to suit changing plant requirements not just at some point but repeatedly over the course of a machine’s lifecycle. IPCs from Beckhoff Automation offer the most advanced, powerful, and forward-compatible choice. PC-based control platforms provide flexible alternatives for integrators who demand both a manageable migration path and higher levels of power and precision from their control system.

Smart hardware and software enable flexible machine control.

The flexibility and upgradeability of IPCs come from the way they implement machine control. With PC-based control, functions previously handled by dedicated hardware are created in automation software, such as TwinCAT 3 from Beckhoff, as function blocks or other code forms. The function blocks and code can be easily moved, changed, upgraded, or altered to meet the system’s evolving needs.

Replacing or upgrading hardware units is a similarly simple process with IPCs. The software-based PLC project can simply be downloaded onto the new machine controller or changed by swapping Cfast cards, bringing the machine back up after modification or service in minutes. Further expandability for machine control is assured via PCIe, PCI slots, and multiple hard drive disk (HDD) slots with RAID-enabled motherboards. All of this gives controls engineers the ability to have one powerful IPC run an entire machine in a centralized control architecture.

PC-based control software also brings many unique features when paired with the IPC hardware. The multi-core and many-core technologies in IPCs and Embedded PCs can handle tasks on one CPU that may have required many separate controllers in the past. With the core-isolation mode in TwinCAT 3, users can harness the full power of multi-core and even many-core technology.

Core isolation enables numerous computation-intensive tasks to be handled by one powerful hardware controller without overburdening the CPU by assigning specific primary control functions and tasks to specific cores. In a quad-core system, for example, a machine builder can set the PLC projects to run on CORE 0, a motion control system on CORE 1, the HMI software on CORE 2, and a vision system on CORE 3. In addition, the PC-based control software efficiently distributes functions across processor cores if the user does not do so independently.

IPCs offer engineering advantages by consolidating software into one environment.

An added benefit of PC-based machine controllers is that any remote access, setup, and connection to the IPC through a secure, encrypted Internet connection requires no special features, programming, or hardware. The IPC brings a wealth of connectivity tools that are much more difficult and expensive to implement with a PLC or PAC. Beckhoff, for example, leverages protocols such as OPC UA so manufacturers, machine builders, and integrators can immediately create cloud-based databases and implement a robust Big Data management system – all standard with a PC-based control platform. No managed hardware or dedicated “black box” equipment is required to make this happen.

These features of PC-based control positively impact production by dramatically reducing the need for scheduled downtime and the frequency of unplanned downtime. Once again, this shows how IPCs offer unparalleled power and flexibility for automation.

Hardware PLCs and PACs perform useful functions, but they are narrow and difficult to change or upgrade. By moving to a platform based on scalable, robust IPCs and PC-based control software, controls engineers gain access to all the benefits and features available from a PLC or PAC. However, engineers can also add flexibility to cost-effectively change and upgrade systems as plant demands necessitate by leveraging PC-based control.