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Product Selection and Applied Technology Handbook 2021
How to Select HMI Software
How to Select HMI Software In addition to assessing developer tools and changing user requirements, OEMs must also now take into account remote access concerns when deciding which HMI software to use.
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arc Andreeson, co-founder of Netscape and the venture capital firm Andreesen-Horowitz, once talked about “software eating the world.” He was referring to the criticality of software to modern businesses and software’s role in overturning established industry structures. And it’s just as true for HMI software. That’s why the decision-making process surrounding HMI software options is so critical. And the first step in this process is making sure the HMI software you want to use can work with the type of display panel used on the machine. Historically, HMIs have been all-in-one units consisting of hardware and software. As a result, OEMs are always looking for ways to make them more cost-effective. The tradeoff is a functional limitation in the software to achieve a balance economically. That’s why more OEMs are now looking towards a decoupled approach, where they can get a relatively inexpensive panel PC or touchscreen computer and pair it with the latest and greatest software. More importantly, software that has management services built in allows a user to centrally manage HMIs by checking health and diagnostics, synchronizing projects, and performing periodic remote upgrades. In this scenario, if the HMI fails, a user can install a new panel PC of any brand, install the same software, remotely send down the application, and be up and running in no time. It is a much simpler approach and much more economical. In some cases, it may not be easy for OEMs to ascertain beforehand the number of required displays and the complexity of each. This issue can be addressed by selecting a supplier with one HMI programming software package that works with their entire family of displays. Also, instead of buying the HMI hardware up front, and possibly choosing the wrong model, it may better to select the programming software you prefer first and create the displays as needed. OEMs can work with a local distributor and download the displays to different target HMIs to make the best selection.
DEVELOPER TOOLS The development environment should be included with an HMI. It shouldn't be separate, meaning that a user would need to download the development environment separately and potentially li-
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cense it separately to be able to connect to the HMI and configure it. OEMs should also provide a way for users to connect the HMI to a central management system. That way, rather than having several hundred isolated HMIs, the user can centrally manage them. Another option is to set up the HMIs to operate independently if the network goes down so that operations can still continue. However, having a centralized management system can help with scalability and maintenance. Having the ability to connect to a centralized management type system to make area-wide changes is powerful. The information technology (IT) side of an HMI system, including mobile apps, email, and access to files in the cloud or on a network, are all common tools used every day in modern Internet of Things systems. An HMI must have these features to ensure data and information is available locally and in a cloud-based platform. Mobile apps for Android and iOS devices provide two-way access to HMIs via Wi-Fi, allowing users to monitor PLC parameters or change set points or other variables. These apps provide dialog interfaces to monitor or control most data variables. These apps should also include features to limit the parameters monitored and controlled. Some of these apps can also upload and download programming software or even delete data from internal memory or external memory devices such as a micro SD card. Because of the increasing need for this type of connected access, cybersecurity practices, such as limiting users and including a robust username and password, must be followed. Good mobile HMI apps can include more than data logs, pictures, and similar files. HMI screen shots, alarm log files, and recipe files can also be uploaded and downloaded. In some systems, if an HMI is connected to a PLC, the HMI can download an updated PLC program, eliminating the need to use programming software to complete the task.
CHANGING USER REQUIREMENTS While the IT side of the system is critical to getting data and information to the right places and people, the operational technology (OT) side plays an important role in controlling the machine or process. Because HMIs communicate with controllers, HMIs are often the first devices to touch the data that comes from a sensor, a digital
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