What is Human Machine Interface: HMI?

Accelerating quality, quantity, economic efficiencies and environmental protection are leading to an increasingly connected process flow and factory floor. In combination with decreased personnel, that has led to processing of increased amounts of information by fewer and less application-specific operators in the control center. It requires a well-designed HMI or Human Machine Interface system to decrease the gap between the production process and the operator via an intuitive visualization system, layers of detail that allow a bird’s eye view down to the minute details, and includes training material and documentation that the operator has on his fingertips.

A well-designed HMI system provides numerous benefits. Chief among them are increased safety, quantity, quality and economic efficiency. Apart from minimizing the risk of disruption in the production process, HMI systems also reduce the over downtime while allowing fewer operators to manage more information with less field-specific knowledge.

HMI provides a means of monitoring, controlling, managing and/or visualizing device processes. For example, an operator panel may allow the operator of an industrial machine to interact with the machine in a visual, graphical way. The operator can easily control the machine by using the touch screen or external buttons, as all readouts and controls readouts are graphically displayed on the screen.

HMIs can be located on the machine, in the form of simple segmented displays or LCD panels of high-resolution. They can be located in portable handheld devices that are battery operated or in centralized control rooms. Machines and process controls can use them to connect the operator with Programmable Logic Control application systems to control sensors, actuators and machines on the factory floor.

For communicating with industrial machines, the usability of the HMI system depends on the processing power of the system, its ability to render reality-like complex screens, quick responses to user inputs and the flexibility for handling several levels of operator interactions. Usually, effective communication requires the HMI to have dynamically changing graphics. This in turn, requires the system to be a high-performance type that supports various resolutions and displays of high refresh rates. For efficient communication between the operator, numerous machines and control systems, it is imperative that multiple connectivity and protocols must be supported.

Industrial automation thrives on real-time communication. Using industrial micro-controllers along with PRU-ICSS or programmable industrial communication subsystems makes it possible to support various popular, certified serial protocols, including those that are Ethernet-based. The PRU-ICSS allows HMI manufacturers easily support industrial communication protocols of multiple types on a single hardware platform. The most important advantage of this platform is that it does not require the support of external ASICs and FPGAs. This offers huge scaling in performance and the integration offers opportunities of software and design reuse.

Portable HMI solutions use several wireless connectivity solutions such as WLAN, Sub-1GHz, ZigBee and BlueTooth. This broad portfolio offers the maximum flexibility when designing for wireless. For example, the WiLink 8 solution provides high-performance BlueTooth and Wi-Fi in one module. The Sub-1GHz performance line is very popular and the most reliable in its range.