A Human Machine Interface or stainless steel hmi, often known as an HMI, is a graphical display that depicts a machine, process, or facility so that the user can intuitively and readily operate and monitor the state of the system being represented.
A straightforward machine will need a straightforward interface for the operator instead of a human-machine interface (HMI). A specific device, such as one that pushes components into the casting of some kind, will require little more than a few indication lights, a few push buttons, and some switches to operate.
To rapidly give you an idea of what the lights and push buttons would accomplish, they would notify the operator that a part was in position and ready for the next step down the line to the next step along the line to the final product. The operator would be aware that the machine was now prepared for the next step, at which point they would add another component to the part and press the relevant button to start the process.
A panel (made of metal, plastic, or even wood) would be manufactured and imprinted with a reduced version of the actual process, and this would take place a very long time ago, much before the brilliant color displays of today.
Holes would be drilled at strategic locations on this panel, and indicators and pilot lights would be inserted there. The panel for the switchgear, such as push buttons and selection switches, would be positioned below this panel, which would be hung on the wall—typically installed at a height accessible from a workstation to provide the operator control over the equipment or process.
Remember that the Human Machine Interface is merely… well… an interface. Keep that in mind. What I mean by this is that a controller, which is often a PLC but combined HMI/PLCs are also available, is in charge of the actual control and intelligence of the system.
By pressing a visual push button on the HMI, the operator can send a request to the controller for the controller to take a specific action. In turn, an effort is carried out by using the intelligence encoded into the controller, with the real action being carried out by the machine itself.
This information can be sent to the HMI from the PLC via sensors installed on the machine.
The human-machine interface (HMI) might be a self-contained touchscreen device designed to work only with a single brand of PLC or controller. At the same time, some are more versatile and may be used with numerous controllers since most communication protocols are incorporated or communication drivers accessible.
Usually, you will see them installed immediately on the enclosure door of a control cabinet. The HMI is the user’s front end to a SCADA system’s controls and databases. Essentially SCADA is the highest level of control of a network of PLCs operating a vast, complicated operation.
Other HMIs use a software package and adapter for a typical PC. The adapter card is placed into the PC to enable connecting to a specific communication media and protocol of the control system.
Depending on the seller and the power and complexity, the software package will have a development system and run-time license. In this manner, a developer only needs one method to create the design of the HMI, and they may purchase numerous run-time licenses that are more cost-effective for usage on each machine.
To get the most out of a Human Machine Interface (HMI), you need to have a design that’s well thought out. A significant amount of variation can result from the designed screens, how they are organized, and how everything is connected to one another.
In most cases, the Main Screen, an Overview screen for each principal region or system, a Current Alarms screen, and an Alarms History screen are good places to begin. Through a collection of push buttons and logical drill-down points that will be located on the Overview screen, users will be able to access other sub-screens that include more specific information.
Straightly navigation to and from related processes and the primary displays is essential.
When representing your machine or process, it is crucial to select the appropriate visuals from the collection that is supplied as well as to create your own, as this will allow the operator to learn more quickly and avoid becoming confused.
The supplied visual libraries feature attractive-looking indicators, push-buttons, meters, numerical displays, tanks, pipelines, valves, motors, blowers, etc.
Food For Thought
Part art, part engineering, and part psychology go into making a fantastic human-machine interface (HMI). It is vital to have a comprehensive grasp of the process, and doing so may really be very enjoyable, particularly for those of us who are more inclined toward artistic pursuits.