plc-hmi

diffrence between plc and hmi...
plc does the same thing,its a interface between mam and machine..so is there a difference

A PLC is the brains of the machine -- it reads inputs and based on it's program, activates outputs.

The HMI is a operator screen - think an ATM where you can push buttons either on the side of the screen or on the screen itself. You can enter in data (what you want to do, how much you want to withdraw, etc) or you can display information (how much you have in your account). The HMI can be used to start conveyors or stop processes, or display information (what product am I making?).

The HMI usually talks to the PLC -- it gives the "brain" it's direction and then the PLC does the work

so i program my plc using a laptop,so this can be called a hmi..rite?

No, you program BOTH the PLC and the HMI with the laptop.

The PLC reads the inputs, evaluates them, then sets the outputs accordingly.

The HMI is a Human-Machine-Interface. It is an easy way for the operator to see specially presented information from the PLC about how the process is running or to be able to input various parameters (speeds, recipes, etc.) into the PLC to define how the process will run. The HMI has no control capabilities. It's merely a "window" into the process.

The PLC can run without a HMI. The HMI, without a PLC, is deadweight...

Think of your computer. The CPU box is like the PLC, processing and evaluating information, setting output actions based on that action, etc. Windows, Linux, ..., is like the HMI.

nowww i get thattt,thankyou