HMI Design: Right Practice 

HMI design technology is one of the reliable practices to build an HMI LCD display. The HMI screens are intuitive screens for users. These screens are efficient in terms of operation and they also do not create stress on the eyes. Control systems have shifted from conventional push buttons to HMI displays within manufacturing. Therefore, the HMI design technology has become a great technology for new installations. There is an array of HMI design-based systems. However, the fundamental principles of a good HMI design system are always the same.

Today, we will discuss the HMI design considerations and different essential considerations. It will help you a lot if you are looking for an HMI screen display. Therefore, let’s start the discussion by sharing some important information on choosing the right HMI hardware.

HMI LCD Display Systems: Choosing a Suitable HMI Hardware

HMI screens are available in different sizes, buttons, colors, and user inputs. It is necessary to know about all parameters and their effect on the design. Most OEMs (Original Equipment Manufacturers) manufacture HMI screens in various sizes. Small size screens are available at lower costs, but they are not suitable for large system designs or when you require more details.

HMI LCD display size plays a key role in how sophisticated the design would be. Usually, it is a possibility to change a smaller screen design onto the big-size HMI screen. It is recommended to shrink elements for larger screens. It is always great to create extra pages that could break down HMI screens.

Usually, OEMs never restrict elements quantity on the specific screen, but a dedicated small screen usually comes with low RAM as compared to larger ones. It leads to some latency problems when adding more elements. Here are the important points to known.

• Always choose an appropriate screen size for your system.
• Never shift the HMI design of a large screen on a small screen. Instead, you should redesign individual screens.

These points are important to keep in mind when choosing an HMI LCD display for your application.

Touch Screen vs. On-Terminal Push Buttons

Although push buttons terminals are not very popular these days, some OEMs, such as Allen Bradley and Siemens are releasing HMI terminals with push buttons support. These terminals enable various HMI designs that depend on such inputs. Additionally, Allen Bradley is still offering support for the push buttons terminals to accomplish navigation.

Such terminals require different configurations as compared to their pure touchscreen counterparts. It is because you usually need to benefit from such functionalities for key functions, navigation, or otherwise. So, the HMI design will be different. Here are the different points to keep in mind in this regard.

• For HMI design controls, minimize the external buttons use. The touchscreen feature is the most suitable solution for every kind of HMI design.
• Physical buttons HMI programs are difficult to move to touchscreens. Therefore, you must plan the software accordingly.

The HMI screen design differs according to the data structure of the HMI. Design patterns also differ for the distributed and machine HMI design.

HMI Screen Design

An HMI LCD display could be simple or complex according to the dictation of the system. Usually, an HMI display should offer the essential information required but shouldn’t confuse the operator. You should break down a complicated system into sub-systems if it needs an array of tags. You can utilize a control system’s physical layout for the HMI design.

Example: HMI Design Plant for Food Processing

1. Plant Overview: A high-level status of every single area as well as critical assets
2. Area Control/Overview: Area overview/control screen for all manufacturing zones; refrigeration, packaging, and production. Control scheme to help a user set high parameters for every production area. For example, production rates, and temperature, etc.
3. Line Control/Overview: Each packaging/production line must have a higher overview screen level so the user should easily check the asset, stop/start line, and parameters adjustment status.
4. Asset Control/Overview: Every single asset on the production line (barcode scanner, palletizer, filler, and case packer) must have a control screen and overview. Such elements help operators in monitoring asset status and granular parameters change like case size and motor speed, etc.

Utilizing HMI Faceplates

You can easily create an interface for an array of elements using faceplates on your HMI screens. Such elements may be motors, pumps, valves, and more. You can design a faceplate as the pop-up on the upper side of your main screen as required. These designs help programmers in developing a particular interface where an operator can monitor data on the main display while making necessary adjustments on the secondary display.

Example: When the operator is monitoring the main overview screen, he may decide to adjust conveyor belts’ speed for slowing down the production downstream.

Position: It is ideal to place the faceplates in the center within the parental screen. However, there can be some exceptions so the screen elements might be hidden in that case.

Size: A pop-up screen that is 50% smaller in size than a parent screen is ideal. However, it relies on the specific needs of the system used.

You must focus on the above-discussed position and size guidelines. They are necessary to ensure a perfect HMI design.

Conclusion

HMI Designs need an engineer to keep in mind various software and hardware aspects for a perfect HMI LCD display. The objective should be to create a design that is efficient, system-specific, and intuitive. When looking for an HMI design terminal, it is essential to consider all protocol requirements, system parameters, and hardware features. When creating an HMI screen, it is necessary to consider screen layout and navigation layout before completing the system design. The navigation dictates how a user would move among the screens. On the other hand, the design of the screen dictates the efficiency of the usage.

Creating the right HMI design is a skillful art. However, certain primary principles and rules are necessary to follow in different industries. You can call us for further queries about HMI designs and screens.