The use of mobile devices, such as smart phones, to access data from the plant floor is becoming more and more commonplace.
The fact that authorised users can now access such real‑time information from anywhere at any time, is highly attractive to many users. It’s also an integral part of the overall drive to increase efficiency.
The technology behind this connectivity is remote desktop, which has been around for many years. This is where a “local” device (usually a computer but not necessarily so) runs its normal programs on the plant floor, as well as a server program.
A remote client (again, not necessarily a computer) connects to this local server (usually via the internet) and displays identical information (i.e the local “desktop”) on is screen. The remote client effectively gains full control over the server as keystrokes and mouse actions from the client are mimicked on the local server, as if the user was entering them on the plant floor.
Apart from supervisory systems, remote desktops are extensively used by help desks that provide remote assistance to computer users.
There are many vendors supplying remote desktop programs: VNC (Virtual Network Computing), TeamViewer, Google Chrome (via plug-in), to name just a few. Even Windows versions as early as XP included in‑built support for a remote desktop.
The sheer volume of packages in the market is a testament to how powerful this technique is and how important it is to those who use it. The technology is now very mature and usage is very high, across a wide range of industries.
Recently, remote desktops have started to be used in the industrial realm. However, instead of computers, HMI (Human Machine Interface) terminals now support a desktop server.
In the case of Omron’s NA series of HMIs, a fully functional VNC server by RealVNC® is available. VNC presents HMI information as it appears, with real‑time updates. Users can have full control access of the HMI and can even access its system menu for low level maintenance functions.
Client programs can be freely downloaded, across a wide range of hardware platforms. These include Windows, MAC OS, iOS, Linux, Raspberry, Solaris and others.
In the case of computers running Windows, clients are merely a simple executable program, which doesn’t even need installation.
In the past, HMIs supported web‑serving for remote access. While still in use, there are several drawbacks to this approach.
Firstly, the nature of the graphical objects used in HMIs do not render easily into the html format used by web sites. Also, the update rate needed to display real‑time data with reasonable fluency is often not obtainable through the Internet.
In short, the web was never designed to display graphical content in real‑time, meaning the end result is often less than satisfactory.
However, Omron has taken remote desktop one step further by utilising the power of mobile technology to access the desktop server. They have created a set of free “HMI Viewer” client apps, for both the Android and iOS (i.e. iPhone and iPad) environments.
Other than running on different mobile platforms, each app has the same functionality and links to a NA HMI running its VNC server via the internet. A recent upgrade means iOS v9 is now also supported.
Once connected, the view on the smart phone screen is the same as what can be seen locally on the HMI on the plant floor, with updates being regular enough to ensure smooth animation.
Once information is displayed, it can be shared (i.e. emailed or texted), printed or saved for further analysis. Users are also able to perform the same control functions via their smart phone, provided write operations have been enabled at the NA’s server. A read‑only mode is available for display only functionality.
Both Omron’s NB and NS HMI series webservers are both supported by these same apps.
Multiple connections can be setup and stored within the app, to save having to re-enter connection data each time.
The apps also support auto‑rotation and zooming to improve the customer’s viewing experience.
The setup of the VNC server in the NA is very straightforward. VNC is disabled by default (for security) and uses TCP port 5900 by the default.
At runtime, a pre‑set password must entered to open the connection and gain access.
Password data is secured by encryption to ensure it’s not compromised.
As VNC is not suitable for transferring files, so FTP is provided for this purpose. It too has its access controller by a server in the NA, and requires clients to enter a password before files can be accessed.
Omron have taken a significant step forward in putting real‑time information in the palm of the decision makers’ hand. They have used the well-accepted and trusted technologies of remote desktop and applied it to smart devices.
Decision makers can now make decisions on a wide range of hardware, at anytime and anywhere in the world, no matter how far away they are from the actual plant.
By Harry Mulder
Harry Mulder is Engineering Manager for Omron Electronics Oceania.
He has been involved in the industrial control industry for nearly 30 years, with the last 25 years at Omron Electronics.
Ph: 1300 766 766