SCADA framework incorporates a rule called HMI. The HMI of a SCADA framework is the place information is handled and introduced to be seen and checked by the human administrators. This interface as a rule incorporates controls where the individual can interface with the SCADA framework. An example of HMI can be seen in picture.

HMI’s are a simple method to normalize the help of observing various RTUs or PLCs. RTUs or PLCs run a pre-modified procedure and spread out over the framework so checking every one of them independently might be troublesome. Additionally, RTUs and PLCs have no normalized strategy to show or present information to the administrator, the SCADA framework speaks with the PLCs through the framework system and procedures data that is effortlessly scattered by the
HMI. HMI’s can likewise be connected to the database, which can utilize information accumulated from PLC’s or RTU’s to give diagrams of patterns, calculated data, schematics for explicit sensors or machines, or even make investigating guides available. In the most recent decade, for all intents and purposes, all SCADA frameworks incorporate a coordinated HMI and PLC gadget making it very simple to run and screen a SCADA framework.

An operator or maintenance personnel can operate and monitor the machine from the HMI. They may include information like temperature, pressure, process steps, and material counts. They can also show very precise levels in tanks and exact positioning of machines. Where machine information used to be viewed on multiple indicators can now be viewed on one screen. The possibilities are only limited to the software and hardware used show in pictures below.

Several HMIs can be used to be connect to PLC device and display it on the screen for different troubleshooting purposes. “Which can save the time compared to connecting a computer, laptop every time we need to perform configuration. Another important benefit of having a HMI, is the fact that plants and other industrial sites can monitor and control multiple machines or other equipment. A small manufacturing facility could even monitor the entire plant on one centrally located HMI. Water and wastewater facilities have utilized this for years by coupling an HMI with a PLC. They are able to monitor locations remotely, like water pumps, as well as equipment inside the plant. HMIs use special software so can be programed them correctly. Different brands of panels use different software accordingly. The software allows the engineer to design what the operator will actually see on the screen, what they can monitor on the screen, what buttons can be pushed, and how the operator can manipulate the machine.

The person programming the HMI has to program each indicator and button to a specific input or output address of a PLC. As a result, the HMI and PLC require to be compatible and be able to communicate to each other. They do this on what is called a Protocol. Different companies use different protocols. Common protocols are Modbus, Ethernet/IP, and Profibus. Once the PLC and the HMI are talking then whatever is programmed into the HMI can be used to monitor and control PLC functions see figure. ”