What is Industrial HMI? How an Industrial Human-Machine Interface (HMI) Works, Examples and Uses, and Best Practices for HMI Design

Definition of Industrial HMI

Industrial HMI is a human-machine interface (HMI) designed for industrial applications. A human-machine interface encompasses both the hardware and software components necessary for the exchange of information between a human operator and a machine — in this case, an industrial system or industrial machinery or equipment. It’s the primary tool that industrial operators and line supervisors rely on for the coordination and control of manufacturing or industrial processes, typically in a plant environment. Industrial HMIs
HMIs are also commonly referred to as a user interface (UI), man-machine interface (MMI), or operator interface terminal (OIT). You may also hear the terms operator panel or operator terminal used to describe an industrial HMI. Essentially, it’s an operations dashboard allowing for users to control the operation of the equipment or device and, typically, providing feedback to operators in terms of performance, active functions, and other metrics. As industrial automation trends continue to grow, well-designed HMIs are increasingly crucial for operational success.

How Industrial HMIs Work

Industrial HMIs run the gamut from the simplistic to the sophisticated and complex. The specific functionality of an interface varies from device to device or machine to machine, depending largely on the functions of the machine and what controls are necessary to coordinate operation. HMIs come in a variety of forms including:

  • Touch display panels
  • Push buttons and switches
  • Mobile devices
  • Computers with keypads

On-screen touch options, buttons and switches, and keypads are used to enable operators to input information and initiate actions. HMIs also output information to operators through indicator lights (typically used to signal whether a machine is powered on or if certain functions are currently running) as well as a variety of other options such as gauges and complex dashboards displaying detailed usage metrics. An interface is truly that — an interface between the user and the machine, relaying inputs and outputs back and forth to allow operators to communicate with and monitor equipment.

Examples and Uses for Industrial HMIs

HMIs can be either stand-alone terminals for a single machine or distributed for more larger, more complex applications. In industrial settings,they’re often used for machine and process control, connecting machines, sensors, and actuators from the plant floor to systems such as I/O and PLC applications. HMIs that transmit data to the cloud or to enterprise systems make it possible to integrate data from dozens of machines for more centralized monitoring and control over an entire plant’s operations.
On the factory floor, HMIs provide valuable data enabling operators to optimize efficiency, such as reallocating staff to compensate for slow production in another area or fine-tuning machine settings to correct performance issues. HMIs may be on the machine or device itself, in a portable, handheld device, or in a central control room.
Human-machine interfaces are used for myriad applications across manufacturing, automotive, processing, and other industries, such as:

  • Food processing
  • Pharmaceutical manufacturing
  • Oil and gas
  • Mining operations
  • SCADA systems
  • Robotics applications
  • Transportation
  • And much more

Most people use HMIs regularly in everyday life, although they may not realize that when they adjust the temperature controls in their vehicles or program their microwave, they’re engaging a human-machine interface to interact with their cars and appliances. In industrial applications, HMIs are often more robust, more complex interfaces capable of handling the volume and complexity of inputs and outputs necessary to operate industrial machinery or plant-wide operations.

Best Practices for Industrial HMI Design

Industrial HMIs are essential for modern industrial operations, but the real benefits lie in usability and effective design. Designing a functional user interface is a complex process that should begin with a comprehensive analysis of requirements, specifications, and all relevant context.
Good HMI design provides viable solutions to many questions such as:

  • What functions must the interface address?
  • What environmental considerations exist? Machines and devices that will be exposed to dust, outdoor elements, or liquids or hazardous substances will require greater durability. Damaged HMIs can render the entire machine useless.
  • Are there regulatory standards to adhere to? Many industries must comply with federal and state regulations, which can limit design options.
  • What visual, auditory, and tactile feedback will best aid operators in accurately controlling the machine?
  • What user input requirements exist? With more complex interfaces, usability can become an obstacle.
  • Does the system require the ability to communicate with other machines, related systems, or central control?
  • What’s the expected lifespan of the machine? HMIs should be designed to last the entire duration of the equipment’s lifespan. HMIs are not typically easy to replace as a stand-alone component. Even when it’s possible, it’s often costly.
  • What needs and requirements does the user have? HMIs designed with the end user in mind — and ideally user input — are better able to address usability concerns.

Industrial HMI design tends to follow the lead of the consumer electronics industry, as operators gain experience using consumer electronics devices outside the workplace and thus become accustomed to certain types of functionality, such as touch screens, for ease of use. The most crucial obligation of an interface designer or engineer is to balance the functional requirements with usability. When it comes to consumer electronics, a poorly designed HMI will be frustrating for the user and can negatively impact adoption and market share. But in industrial HMI design, a poorly designed interface can result in undesirable operational consequences, errors, and miscalculations with devastating impacts on performance and safety.

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