HMI - Human Machine Interface

Wireless technology transforming the user experience in industrial devices.

Wireless human-machine interface (HMI) for industrial applications

Industrial field devices are traditionally provisioned, programmed and diagnosed using complex local user interfaces and cable-connected PC programs. Bluetooth is an ideal technology for future HMIs. Using Silicon Labs pre-certified Bluetooth modules and mobile application tools allow streamlined user experience modernization and fast time to market.  

How wireless technology can transform your user experience

A HMI for an industrial field device introduces imposes a great design challenge. Traditionally, the designers are limited in physical space, they need to consider the environmental conditions, and any ports for external connections require galvanic isolation for safety. To resolve these challenges, the designers have to make trade-offs that can adversely impact the user experience because of the multiple compromises made during the design process. Complex user interfaces lead to poor perceived usability and the users may opt not to use the full capability of the device because of difficulty in configuring, operating or maintaining.

The use of Bluetooth technology in industrial field devices is still in its infancy, however, it is gradually gaining more footprint due to its superior benefits over the traditional design approaches. Modern Bluetooth pre-certified modules include everything that is needed to build an intuitive user experience. The modules come also in very small form factors, which means that they can be integrated into even space-constrained devices. The modules sizes are starting at 6 x 6 mm. The power consumption of Bluetooth modules is optimized to a level, where it is a feasible option for battery-operated devices.

Bluetooth is a wireless technology, which means that external connections between the field device and the user's end device do not require galvanic isolation. This can provide substantial reductions in materials costs. It also reduces the testing and validation as there are less exposed interfaces that would have to be verified for safety. Because of the wide adoption of Bluetooth technology, it enables use of various portable devices as the user interface to the device. When the designers are no longer restricted to a couple of pushbuttons and a small display, they can deliver user interfaces to the customers that highlight the product benefits and allow better differentiation against the competition.

Industrial devices can be installed in challenging environments, where the devices can be exposed to dust, salt water, humidity, and other conditions. Any inlet that goes through the device enclosure needs to be carefully designed and protected. With a Bluetooth-based HMI, the physical connectors, pushbuttons, and screens can be minimized simplifying the device design. From the customer point of view, they have fewer things to maintain, which drives cost savings for them. The field devices may also be installed in hard to reach locations, which makes conventional cable-based interfaces cumbersome to use. With Bluetooth, the user can take a remote connection to the device from a safe position using a handheld device.

Often the external connections from an industrial field device are based on RS-232 serial communications due to its versatility and widely available components. These types of interfaces present an excellent opportunity for wireless. Bluetooth modules that take standard UART as an input and require zero Bluetooth programming knowledge are an excellent option for HMI innovation. In addition to the pre-certified modules, the mobile applications used as the primary user interfaces are a key factor in the time-to-market and development costs. Pre-determined mobile application frameworks that abstract the Bluetooth operations substantially simplify the design process and reduces the development time.

Silicon Labs offers a broad portfolio of pre-certified Bluetooth modules for human machine interface applications, including the world’s smallest system-in-package Bluetooth module for space constrained designs. Our developer tools include mobile integration software designed to expedite application development. Our Bluetooth Xpress products and their mobile application frameworks are ideal for transforming an existing human-machine serial interface into a robust, future-proof user experience.


Human Machine Interface Block Diagram

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