Process challenges that lead to system integration
When industrial workstations are located in a hazardous area, you often need to invest in training for qualified personnel who must comply with safety guidelines as well as deal with the physical layout and restrictions of facilities that include hazardous areas. Investing in equipment that likewise meets the challenges of the hazardous area is a must.
It's rather time consuming to walk back and forth between the production area and the control room to access a local HMI system. It's much more efficient and convenient to monitor control room functions locally, right inside the process area, using properly certified equipment that is rugged enough to withstand the tough environments external to the control room. Being closer to the process empowers you with greater control and monitoring capabilities in real time.
How to handle the hurdles
There are several ways to better keep track of your process with system integration, including:
- Keyboard video mouse (KVM)
- Virtual network computing (VNC)
- TeamViewer or a multitude of other remote access and control programs that are similar to VNC
For the purposes of this blog, we’re going to take a closer look at just the first two options.
Legacy KVM technology typically consists of industrial keyboards, video monitors, and pointing devices placed within several feet of a remote PC or thin client. A KVM extender is often added to the mix. A KVM extender is basically an extension cord that transmits KVM data over longer distances from a local PC, in, for example, a control room.
VNC transmits keyboard and mouse movements between a local PC or server and a remote industrial workstation. It is the user’s choice whether the remote unit is a PC or thin client. VNC is an open architecture that crosses platforms and is in widespread use. Many packages are available. VNC is licensed for each desktop you wish to control. Windows computers have a single desktop, so they require a single license each. Mac OS X, UNIX, and Linux computers can host virtual desktops, so they require a license for each one you wish to control. Pepperl+Fuchs offers a remote monitor which implements VNC using UltraVNC.
KVM vs. thin client, the pros and cons
With KVM, you can save on the license fees for software programs, but the tradeoff is a higher hardware cost, especially for fiber optic KVM. In contrast, with a thin client system, you get a lower hardware cost because the KVM transmitter and receiver hardware is not required. Most thin clients use relatively inexpensive processors with minimal amounts of RAM and small hard drives since the major processes and computations are not done locally on the thin client, but rather on the host or server PC they are connected to.
RealVNC® offers a free license with the most basic remote control features for individual private use, a richly featured, personal license at $30 per desktop for personal and business use, and a fully featured license at $44 per desktop. VNC crosses platforms (that is a big pro). You can use VNC with Windows, Mac OS X, UNIX, and Linux.
Table 1 offers a comparison between KVM and VNC.
Table 2 sums up a few of the advantages and disadvantages of KVM vs. VNC.
The bottom line: outdated KVM is being replaced by VNC
The trend is for VNC to replace the older KVM setup. The lower hardware cost, higher reliability, and platform diversity form a winning combination.
Pepperl+Fuchs can help you make the switch. We offer a complete HMI solution for remote access and control applications. This solution includes the design and testing of both the hardware and software.