Connect dozens of HMIs to one industrial PC

A new display and visualization concept from Beckhoff, CP-Link 3, allows connection of up to 255 Ethernet opearator interface panels or panel PCs to one industrial PC.

04/08/2009


A new display and visualization concept from Beckhoff Automation provides for flexible connection of up to 255 Ethernet human machine interface (HMI) panels or panel PCs to one industrial PC. CP-Link 3 is based entirely on non-proprietary hardware and the IP protocol for transfer of images. Networking can be done using standard, cost-effective Ethernet cables (CAT 5), which are suitable for drag chains.

When Beckhoff introduced CP-Link 1 in 1998, it began offering independent display elements (control panels) that were separate from the control level. While CP-Link 1 and CP-Link 2 solutions are based on special hardware components, CP-Link 3 is a pure software solution based standard technologies: 100 Mbit/s Ethernet and IP protocol. The display contents are captured by a virtual graphic adapter in the host PC and sent using Ethernet to one or more Beckhoff Ethernet panels running Microsoft Windows CE, XP Embedded, or XP. For display communication, TCP/IP or UDP/IP (multicast) can be used depending on the operating mode.

The solution creates three operating modes with regard to screen display:

  • Single desktop: A virtual graphic adapter shows the image of the host PC on a display connected via Ethernet.

In multi desktop mode, an input can be made to each panel at the same time. The displays can be interlocked (mouse and keyboard) to coordinate the inputs. The host PC transfers image signals, touch screen and special key functions as well as “Virtual USB” to the panels. Virtual USB emulates a USB root hub in the host PC. If a USB device is plugged into an Ethernet Panel, the virtual hub logs the device onto the operating system of the host PC and transparently transmits the ensuing communication. For the operating system, the USB device behaves as though it was directly connected to the PC. Virtual USB transfers the standards USB 1.1 and USB 2.0.
The new CP-Link 3 concept is supported by all Beckhoff Ethernet panels and panel PCs. Users simply need CP-Link 3 client software and Microsoft Windows CE or XP Embedded as an operating system to implement this new technology.
Beckhoff also recently introduced control panels with integrated RFID readers.

Renee Robbins , senior editor
Control Engineering News Desk
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