What is Human Machine Interface (HMI) Software?

Human Machine Interface (HMI) Software Functionality

The functionality of Human Machine Interface (HMI) software can vary considerably.  Many software packages are HMI clients used with a variety of control products, such as DCSs, PLC, PACs or PC-based data acquisition systems.  In addition to performing visualization functions, many of these HMI client software packag-es are also used for performing monitoring functions, such as alarming, as well as for data storage and printing management reports.  Some of the more sophisticated packages also perform control functions.  ARC considers script language programming to be an inherent function of an HMI client software package, rather than control and programming. 

This analysis also includes sales of related control and programming modules by the Human Machine Interface (HMI) software and services suppliers.  These HMI-related software modules are typically packaged as optional add-ons, or alternatively as components of a family or suite of products.  One type of control and programming module is PC-based control, where the functions typically performed by a PLC, PAC or other controller are executed on standard PC hardware.  HMI control and programming modules can also perform specif-ic functions, such as basic regulatory control, batch control, supervisory con-trol, and statistical process control.

Another category is supervisory software, typically server based, where production management functions are incorporated into the HMI software.  These segments reflect how HMI software and services suppliers are ex-panding their application space and represent important growth areas for the suppliers.  Server-based HMI supervisory software packages typically perform functions, such as process visualization and animation, data acqui-sition and management, process monitoring and alarming, management reporting, and database serving to other enterprise applications.  Another driver towards server-based supervisory HMI software is the growth of mobile enterprise application platforms, such as smart phones and tablets that are accessing applications securely from any location.

Human Machine Interface (HMI) Software by Operating System

ARC segments the HMI software market by operating system.  In this view, market size and five-year forecast show current and expected revenues and units for HMI software packages as determined by the operating system used as the software platform.  This is a key driver in the HMI software market in terms of customer preference and supplier differentiation. 

Most major suppliers to the HMI software market offer packages that utilize Microsoft Windows 10, Windows 8, or Windows 7 and Microsoft Server 2012 or Server 2008 as their primary software platforms.  The reason for the emergence of server software is because HMI software packages are being driven towards client/server multi-tasking applications at a faster rate than running on standalone machines.  Older operating systems, such as Win-dows XP or Server 2003, also cannot address some of the latest security con-cerns expressed by end users and OEMs, which in many cases is a factor driving the HMI software upgrade.

Windows CE has become the dominant operating system for HMI software packages running on smaller, less powerful, dedicated devices, such as smart phones, tablet PCs, wireless remotes, and low-cost HMI devices.  Windows CE strengths include the ability to run real-time applications without extensions; fit small applications where cost, size of memory and low power are major constraints; and run on specialized hardware plat-forms designed to minimize per unit costs.

As HMI software shifts from standalone computing towards client/server architecture to handle applications, such as HMI server virtualization, de-mand for the ability to view and/or control a process via the Internet or cor-porate intranets increase dramatically.  Demand continues to increase for HMI “thin-client” products, which users can use to view and/or control a process from a computer or browser-embedded device on which no HMI software is installed.  The user, through a standard web browser, will enter an IP address, then enter a password, and based on the access level config-ured in the server, be able to view and/or control the process.  Thin-client HMI terminal services software also lets users remotely execute applica-tions.  It offers some advantages, since it is typically part of the web server’s core operating system.

Operating systems, such as Apple’s iOS and Google’s Android, are the foundations for a great majority of the smart phones and tablet PCs.  These devices can be used for thin client browser access to view HMI data, most of which supports HTML5.  However, when the HMI software package itself is embedded in a smart phone or tablet PC, the device typically will be run-ning an operating system capable of running real-time applications without extensions, such as Windows CE. 

Some suppliers still support other operating systems to meet the needs of legacy systems and certain real-time applications that require better perfor-mance than can be provided through real-time extensions.  Some suppliers also support applications based on Java and Linux. 

Java is supported due to Oracle’s initiative with control and software sup-pliers.  Java provides base functionality for plant browsers on corporate in-tranets and over the Internet for thin-client HMI software.  It provides port-ability and platform independence, and is used with the integration of man-ufacturing and corporate networks.  HMI software and services suppliers have been keeping an eye on Linux for some time to see if support is devel-oping at the user level.

To date, few HMI software packages use a Linux software platform.  HMI software and services suppliers, such as Inductive Automation and Vista Control Systems are developing Linux packages in an effort to drive the ad-vantages into the marketplace.  Linux features include a free UNIX-type op-erating system with true multitasking, virtual memory, shared libraries, demand loading, memory management, TCP/IP networking, and other UNIX-like features.  Developed under the GNU general public license, the source code for Linux is available to everyone at no cost.