What is a PLC?
The PLC stand for Programmable Logic Controller. They are most usually applied in industrial applications, it generally lacks a keyboard, mouse, and a monitor, as it is normally programmed to run a system or machine.
The system or machine user seldom interacts directly with the program of PLC. When it is required to either create or edit the program of PLC, a PC is usually connected to it.
The PLC has a significant capability for real-world I/O connectivity. Most models of PLC feature a huge variety of interchangeable modules of I/O, which let for suitable interfacing with virtually any kind of laboratory or industrial equipment.
Mainly PLCs are programmed in a Ladder Logic. Ladder Logic is fundamentally a program of Boolean logic-solving with a graphical user interface planned to look like a basic wiring diagram, common to all electricians industry.
What is a HMI?
A HMI sometimes also known as a MMI. HMI is stand for Human to Machine Interface and MMI is stand for Man to Machine Interface. Even though MMI is not supposed to be politically correct now that term less and less.
The job of HMI is it to translate the signals and intentions from a human into signals of electric for the information system of machine to use. Therefore in doing so, lets the human operator to create interactive changes in the data and software process.
HMI its quite frequently has a display integrated into them as well to allow the operator to distinguish the relevant data to the action being carried out.
The computer evolution has and continues to have a big impact on the industry and society. We are in an amendment cycle with the current evolution of computer, but more significantly we are trying to amend to meet the transformations for the next decade. Software and hardware are persistently being improved. Computers are now more powerful and will ultimately give a human to machine interface.
While other tool is PLC hence and based supports interface. One of the equipment is said to be technology of Human Machine Interface based and is said that it does not comply for network interface or computer. It has a port of USB which can help to download data.
From the qualifications below are the some diversities between HMI and PLC
1. There will be unit display in HMI with the buttons of function.
2. It is able to monitor what current happenings during executions.
3. HMI is able to operate in both manual and auto mode.
4. It is able to change the set point.
5. HMI is usually a touch screen of the PLC
1. There is no unit display.
2. The user can not monitor what happening in the execution in the PLC.
3. PLC called as programmable logical circuit.
4. PLC running only in auto mode. User can not proceed if there is error during the operation till it repaired or corrected.
5. The set point can not be adjusted in PLC. If requires to be adjusted then the program license must be downloaded.
PLCs are inserted type controllers of ladder logic with set-points of programmable parameter for a control function of automation. Commonly, HMI is a PC based interface with frequently configurable software and broader functionality.
An HMI will need far bigger control and validation, and will be judged for the compliance of 21 FR pt11. It will all base on the HMI/software functionality that you have for the FBD. It would that it is unlikely the HMI can not be obsessed up to a PC or printer if you need it.