Human-machine interfaces (HMIs) are graphical interfaces that allow interactions between humans and machines. In the industrial sector, HMIs are used to control manufacturing lines and industrial equipment. Traditionally, programmable logic controller (PLC) modules are connected to an HMI to carry out a command once it is implemented on the HMI device. However, there are inherent shortcomings to using HMIs with PLCs, which is leading engineers to consider alternative options.
The biggest shortcoming with HMI and PLC systems is that they are highly specialized and lack flexibility. PLC modules can only carry out simple commands, so many devices are needed to implement different functions. Furthermore, a critical component of modern control systems is the collection of data – if there is a network outage, PLC modules are unable to transmit vital operational data.
Panel PCs can also be utilized as an HMI with the right software. Unlike traditional PLC modules (which are usually configured for one highly specialized task) a PC can control many different functions at one time. If the PLC module fails, a replacement device must be found that is configured for that task or must be configured at that time, which can cause extended operational downtime. With an industrial computer this isn’t necessary because it can be preprogrammed and swapped in immediately.
PCs require less equipment to fulfill the same computing operations, since one panel PC can be used to carry out all the different parts of a process. When using PLC modules, differently configured devices must be used for each task, which greatly increases the number of access points in a facility, taking up valuable space. The large amount of PLC modules necessary for a complex process can be consolidated with a few panel PCs capable of the same job.
The growing trend: Panel PCs
Increasingly, professionals are turning to panel PCs as an HMI because of their flexibility and versatility. As software develops and becomes more complex, better technology is needed to fully take advantage. Panel PCs are capable of storing data locally, unlike the traditional HMI/PLC systems that need to transmit data to servers. They also have much higher computing power and thus are able to manage complex tasks more easily.
Another huge advantage of the panel PC is the built-in toucscreen. The entire production line or equipment process can be controlled from one central point. Instead of handling a control panel with an array of confusing switches and buttons, users can easily utilize a touchscreen interface that has the entire control system visually mapped out. There are different touchscreen types available depending on the application, like resistive if employees need to wear gloves or projected capacitive if they need screens with more than one touch point. This gives these PC systems more versatility.
A panel PC also allows for better visual representation of a control system and provides real-time data acquisition. They increase productivity by providing an extremely user-friendly interface, so as screens get larger and have higher resolutions, users can more clearly observe the equipment. Panel PCs often employ a fanless cooling system, which means that they have a long usage life, low failure rate, and high system reliability. Built with industrial-grade components, industrial panel PCs can be placed in hazardous or harsh environments and last far longer than commercial-grade computers.
Industrial and manufacturing processes are only going to get more complicated. To keep up with the changing technological landscape, companies must be sure that they are leaving outdated control and supervision systems behind. Moving from specialized HMI and PLC modules to more flexible PC solutions is a major benefit as software continues to evolve.