Replacing stationary HMIs with contextual HMIs

Mobile devices with human-machine interface software can be used in the context of the worker’s location and work that needs to be performed. Contextual HMIs allow workers to increase efficiencies and improves worker safety and security.

By Ed Nugent, PcVue Inc. June 2, 2018

Stationary human-machine interface (HMI) displays are being replaced by contextual HMIs. Whether a one-line display or a dedicated touchscreen, stationary HMIs are failing to meet mobile operators’ expectations. Today’s workers want information at their fingertips and they are looking to mobile devices to fill that need.

A maintenance engineer is wasting time repeatedly moving back and forth between a stationary HMI and the physical location where maintenance is being performed. In many cases, maintenance work is located on the opposite side of the equipment and away from the stationary operator HMI. This is the case during commissioning, troubleshooting repairs, and during equipment changeover and startup when the maintenance staff needs to confirm equipment state or set a control parameter, for example. 

Elements of contextual HMI infrastructure

Contextual HMIs are designed to solve this issue by providing greater mobility for engineers. On a mobile device, they eliminate the difficulty of navigating a screen designed for a workstation on a much smaller screen, as is the case when using a web browser to display a workstation HMI. Contextual HMI means in the context of the worker’s location and work that needs to be performed.

If the contextual mobility server is aware of the mobile device’s location and has validated the user the HMI can push specific HMI components to the worker’s mobile device. For security and safety reasons, the HMI must be automatically removed from the device when the worker moves outside of the proximity of the equipment being worked on.

To benefit from contextual HMI, it’s important to deploy an infrastructure that isn’t complicated. A contextual mobility infrastructure is centered on a mobile device. It takes advantage of standard indoor and outdoor geo-location technologies found on nearly all modern mobile devices to provide a dynamic and contextual HMI based on the worker’s proximity to a predefined geographical zone. A zone may be an entire facility, a room, or it may also be in the direct proximity of a specific piece of equipment.

Geo-tags such as Bluetooth low energy beacons (iBeacons), near-field communications (NFC), and quick response (QR) codes are placed strategically in these geographic zones of control known as geo-zones. A secure proximity services mobile application on the device receives the identification of the geo-tags that are within range of the device. If more than one is in range, the geo-tag with the stronger signal is used. This concept, known as "geo-fencing" allows actions based on control zones.

The mobile application communicates with the contextual mobility server using a standard internet protocol (IP) connection through Wi-Fi or a cellular network. The contextual mobility server is responsible for evaluating and responding with the necessary information and controls pushed to the user’s mobile device automatically. The required information and control is evaluated based on the current geo-zone and as determined by the mobile worker’s login profile.

There can only be one supervisor of equipment so neither the mobile app nor the contextual mobility server communicates directly to the equipment. The supervisory system, supervisory control and data acquisition (SCADA), or building management system (BMS) retains responsibility for communicating with the equipment or other assets that it supervises. The contextual mobility server must reflect the equipment’s real-time status variables or tags by using OPC or other real-time methods to synchronize with the SCADA or BMS.

The cornerstone of the infrastructure is the contextual mobility server and its contextual logic engine (CLE). The contextual mobility server maintains a database that associates geo-zones and user profiles with information, equipment controls, actions, and events. The CLE determines the appropriate actions and triggers the distribution of information and control elements to the mobile worker. This includes additional resources (drawings, schematics, etc.) workers need to do their jobs.

Operations and maintenance personnel now have the relevant HMI they need for situation awareness and intelligent control in their workspace. The relevant information is pushed to their mobile device automatically when the application and contextual mobility server detects when the device has entered a geo-zone. This eliminates requiring navigation designed for a computer monitor, when using a much smaller mobile device screen. It provides improved performance and operational efficiency while also increasing safety.

The connected SCADA or BMS system is enhanced when they are augmented with contextual HMI capability. Knowing the mobile worker’s location and routes provides the ability for control room assistance for efficiency, safety, and security issues. For example, the control room can see where workers are or have been to recognize unauthorized access to restricted areas. They can dispatch the nearest certified technician in the case of a maintenance emergency and assist with safe passage routes if evacuation is necessary. 

Mobility security

A private and secure internal messaging system is also an essential element of a contextual mobility infrastructure. It allows mobile workers to exchange information with each other and with the control room. This includes text, photos, videos and audio recordings.

Integrated messaging is preferable to alternatives such as short message service (SMS) because the messages become a permanent part of the operations and maintenance (O&M) record. An electronic messaging system is useful for shift handoff since messages can be directed to a group or individuals. Deploying a contextual mobility infrastructure includes ensuring that there is access to the network for the mobile device in all work locations. Designing geo-zones and placing geo-tags is the next step. Configuring the contextual mobility server is a matter of defining the content that needs to be sent in each geo-zone and user profile.

While there is a cost associated with deploying a contextual mobility infrastructure, eliminating stationary HMIs, increasing efficiency of the O&M team, and improving overall safety and security will offset the cost.

Ed Nugent is the COO at PcVue Inc. Edited by Emily Guenther, associate content manager, Control Engineering, CFE Media,


KEYWORD: Human-machine interface (HMI)

  • The infrastructure of a contextual HMI
  • The benefits of deploying a contextual HMI.

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About PcVue Solutions

PcVue Solutions are available in North America from PcVue Inc. and from ARC Group affiliates around the world. In an increasingly communicating universe, PcVue Solutions innovates with software that optimize the interface between people, connected objects and supervisory systems. PcVue Solutions, including ContextVue mobility server and SnapVue mobile apps are a patented innovation for contextual HMI developed by ARC Informatique, the affiliate of PcVue Inc. in Paris. Please visit the PcVue Solutions website for more information.