Interfacing PLCs and HMIs
In Chapter 9, Deep Dive into PLC Programming with TIA Portal, we learned how to use pushbuttons to start and stop and also how to use a lamp as an indicator that shows when a load is on or off.
As we discussed earlier, HMIs allows human operators to interact with machines via a PLC. This means that a PLC is required to communicate with the machine.
Here, in this section, we will learn how to interface a Siemens HMI (KTP 400) and a Siemens PLC using Profinet as a communication protocol. We will use TIA Portal to program the PLC and develop the HMI application using WinCC, which was installed when we installed TIA Portal in Chapter 8, Understanding PLC Software and Programming with TIA Portal.
By the end of this section, you should be able to interface PLCs and HMIs such that the HMI can be used to start and stop and get feedback on the status of a machine (for example, a motor).
We are already familiar with the Siemens S7 1200 PLC (CPU 1211C). The...