Updated June 2019 || Human machine interface (HMI) software is programming that gives operators a way to manage machine command panels. Interaction is through a graphical user interface (GUI) that facilitates information exchange and communication between two types of HMI — supervisory and machine level. Generally, programmers write HMI software for either machine-level HMI or supervisory-level HMI, with applications suitable for both types. Such software has high upfront cost, but is inexpensive long-term thanks to the way it reduces redundancies.
Case in point: Even lower-tech applications (in which most machine interaction is via switches and pushbuttons) entry-level HMI offerings are making inroads — as they often reduce interface-part count and simplify controls. More sophisticated applications benefit in a different way: Pharmaceutical and medical machinery use the latest HMI features to differentiate from competitive offerings.
But no matter the performance grade, selecting HMI software starts with an analysis of product specifications and features. What kind of GUI will the machine operator need? Will operators need to view diagrams, digital photos and detailed system schematics? Other considerations include system architecture, performance requirements, integration, cost of procurement, and operations.
Sometimes, an HMI unit can be programmed to perform some basic control functions as well, such as editing servomotor parameters and even issuing global commands to other control axes on a machine. This places them well beyond a basic type of HMI with only simple functions such as observing processes or making very simple changes to some individual variables or parameters or setpoints.
HMI software editors are available to provide touch screen functionality through a multitude of dimensions and colors. Additionally, they offer control functions for industrial automation machines. Programming can be done using Windows-based and screen editor software. It can permit quick editing of schematics and set suitable communication protocols.
HMI accessories complement the displays based on the requirements of the operator. Depending on the complexity of the application, there are a range of I/O options available such as the number of digital or analog inputs or outputs, and communication protocols range from simple RS-232 links to more advanced protocols such as CANOpen, SERCOS, and Ethernet-based communications.
Communications on multiple networks are supported through ControlNet and DeviceNet. ControlNet is a control-level network that provides high-speed transmission of time-critical messaging data and I/O data. DeviceNet handles industrial devices like drives, limit switches, motor starters, operator displays, photoelectric cells, and valve manifolds to personal computers (PC) and programmable logic controllers (PLC). The use of both communication systems provides HMI software data management between the machines and operator interactions.
More sophisticated HMI software is structured around mobile, portable platforms such as the Microsoft Windows CE platform, a scalable version of the Windows operating system for handheld devices. This presents a cost-saving value as the operating systems are distributed on machine-level embedded HMI, solid-state open HMI machines, distributed HMI servers, and portable HMI devices.
HMI software that’s growing most rapidly are programs that let users remotely monitor and control HMIs from smartphones, tablets, or offsite PCs. Traditional setups only let users get to the HMI on the factory floor, but this new cloud-based HMI software gives operators remote access lets them check machines from anywhere. Sometimes called web-based visualization, this is particularly helpful where machines run in hard-to-reach places. Related innovations in HMI software even let remote users make on-the-fly changes to machine functions (for variable production output).