Bringing remote desktop to the palm of your hand
The use of mobile devices, such as smartphones, 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. 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.
Securing password data
The setup of the VNC server in the NA is very straight forward. 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.
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. With a degree in computer science, his experience includes sales, engineering and product management. He currently manages an engineering team across four states but still enjoys getting involved with day-to-day problem solving.