Chapter 14: Downloading to the HMI

Human Machine Interfaces (HMIs) found within a project also require a download in a similar fashion to PLCs. During this download, items such as the graphical screens, connection configurations, user administrations, and more are sent to the HMI's runtime system. In order to download to an HMI, additional steps are required in the TIA Portal project than that of a PLC, with more steps required to be confirmed by the programmer performing the download.

In this chapter, we will cover the following topics:

• Connection parameters
• Downloading to an HMI
• Simulating a unified HMI
• Security considerations

Connection parameters

HMIs are designed to offer an interface for a machine or process, hence the name Human Machine Interface. Before the HMI can be downloaded to, a connection must be made between the PLC and the HMI. This connection is then used to pass information between the HMI and the PLC.

Note

Connections must be made before the HMI is able to access variables created in the associated PLC.

TIA Portal offers many different communication drivers for HMIs, allowing communication between all Siemens devices and even other vendors such as Allen Bradley and Mitsubishi. This enables a single HMI to talk to multiple PLCs, even if they are not of the same type.

Creating connections

Inside the project tree and within the HMI object, you will find the Connections object. By opening the Connections object, the Connections window opens. Here, connection definitions can be made, including those connections that are not Siemens devices.

A new connection can be added by...

Downloading to an HMI

The principles behind downloading to an HMI are very similar to that of a PLC. Starting a download is performed in the same manner – by selecting the HMI in the project tree and then clicking on the Download button. Additionally, the right-click menu can be used to initiate a download.

When the Load preview window is displayed, the options differ from an HMI to a PLC:

Figure 14.6 – Load preview

The HMI Load preview window has more actions available than the PLC Load preview window, and these actions directly affect how the download is completed:

• Load Runtime: Under certain conditions, a Delta download option is available rather than a Full download option. Delta download allows the HMI to continue running during the download process, and only changes are downloaded as opposed to the entire download. When a Full download occurs, the HMI must be stopped temporarily, and this happens automatically.
• Runtime start...

Simulating a unified HMI

TIA Portal V17 can simulate a unified HMI on the localhost (that is, the laptop/PC being used to develop the project). The simulation can be started in the same way that a PLC simulation is started – by clicking on the Start simulation button from the toolbar.

Unlike with a PLC, no simulation window or program will open. Instead, TIA Portal starts a background service that runs the unified simulation. This can be accessed by opening the SIMATIC Runtime Manager window, which can be accessed from the Windows Start menu (type in SIMATIC Runtime Manager after opening the Windows Start menu):

Figure 14.7 – SIMATIC Runtime Manager

The SIMATIC Runtime Manager window displays any active runtimes, including simulated runtimes. Figure 14.7 demonstrates this by displaying a project called Chapter 12 that is active and running with a Type value of Simulation. This is the runtime that was used for the Chapter 12 project.

Note...

Security considerations

In TIA Portal V17, security standards have been implemented and Siemens recommends using security methods whenever possible. These include encryption transfer but extend beyond this to items such as OPC UA.

With a vast variety of connection protocols and interfaces available on different hardware platforms that can run the unified environment, Siemens has detailed its security considerations in a freely available document that can be downloaded from the Siemens website or via the following QR code:

Figure 14.11 – The QR code to Siemens Support for HMI security considerations

If the QR code in Figure 14.11 cannot be read, the same information can be found by searching for Security guidelines for SIMATIC unified HMI operator devices on the internet.

On the support site, there is a PDF file spanning over 40 pages that lists, in detail, all the security considerations and steps to enable these security functions. It is unlikely...

Summary

In this chapter, we covered the steps required to download a unified HMI, including how to simulate and access simulated HMIs. Downloading to HMIs is similar to downloading to a PLC. However, many different options directly affect how the download proceeds and what happens to the runtime of the HMI once the download has finished executing.

The unified environment is capable of running on different hardware platforms, even PCs. The download procedure for all of these should be the same. However, there might be small differences in the Load preview window depending on the capabilities enabled (such as OPC UA and other interfaces).

In the next chapter, we will focus on writing tips such as simplifying logic, naming conventions, sequences, and where to find further support.