Separate IT and OT, Advance DT
November 8, 2024
Nearly every automated machine or system in today’s world has some sort of interface that allows a human worker to interact with it and that is where an HMI comes in. These human-machine interfaces (HMIs) are crucial because they allow for more precise control over the system, increased safety, and greater productivity. HMIs are easier user interfaces than most automation components. They are compatible with a wide range of equipment and rugged enough to withstand harsh industrial environments.
If you are looking for an HMI for your automation system, this is what you should be evaluating as far as performance and features.
Uses for HMIs
There are four major uses for HMIs in an automation system:
- Allow an operator to enable machine functions to be performed via an intuitive visual interface
- Observation of the system’s input and output status
- Monitoring the health and performance of the automation system
- System feedback and tracking
With these four uses in mind, decide which are the most important to you and see which HMI best fits how you will be using it.
Consider Your HMI Environment
The ruggedness of HMIs can vary greatly, so consider the performance environment for the HMI. The HMI must not only be able to operate in this environment, but it must continue to do so for years (unless you want to replace it quite frequently).
Many of the environmental conditions that could affect the performance and usability of an HMI include:
- Splashing liquids
- Extreme temperatures
- Bright sunlight
- Chemicals or airborne contaminants
- Excessive dust or other particles
- Unexpected impacts
While it doesn’t affect the lifespan of the HMI, it’s also important to consider the lighting of the environment. Is it a low lighting or low visibility setting? Will the HMI be outside where direct sunlight can impact your ability to read the screen? It’s important to look into the brightness and backlighting settings of your chosen HMI to see if you will be able to see the touchscreen and operate it based on the available lighting.
HMI Display Sizing
HMI displays vary greatly in size, from very small to quite large. While some operators may prefer a larger display for easier use and better viewing from a distance, consider the real estate that larger displays will take up in exchange for these abilities (they also tend to come with a higher price tag). Smaller screen sizes are more optimal if space is an issue, but it means touchscreen controls will be smaller and harder to view from farther away. Also, consider the resolution of the display. More pixels mean clearer pictures and graphics, especially as the size of the screen increases.
Choose a Touchscreen Type
There are two main types of touchscreen control.
- Capacitive Touchscreens: these use the human body’s electrical field to process inputs. They are highly receptive and accurate, often offering more control and a greater number of swiping inputs to streamline the process of inputting commands.
- Resistive Touchscreens: these require physical force to input commands. They are slightly less receptive but are generally necessary if operators will be using gloves while inputting commands. Gloves tend to block the body’s electrical fields and prevent capacitive touchscreens from processing button presses.
Communication Protocols
Depending on the manufacturer, HMIs often support hundreds of communication protocols for various PLCs and Motion Control systems.
How Much Memory You Need?
The memory constraints of different HMIs can vary, and some are equipped with extra slots for memory capacity to be upgraded. Memory can affect everything from processing power and performance to more advanced features and calculations.
Next Steps
Need help choosing an HMI panel for your automation system? We can help. Get in touch with Motion Automation Intelligence automation experts today.
