Stable long-distance relationship between HMI and machines

Stable long-distance relationship between HMI and machines

With Extended Display Link, Rafi presents a new gateway technology that enables the fully functional connection of touch-based HMI panels to application controllers located up to 100 m away. More and more manufacturers of machining centers, mobile machines or commercial vehicles are equipping their products with high-performance central controllers in order to save the use of further decentralized computing units. Because the control of HMI displays can also be outsourced to the central CPU on this basis, considerably leaner operating panels without their own control units and cooling systems can be used in many applications.

However, longer distances between HMI panels and the application CPU can lead to problems with the transmission of input, video and sound data, since standard interfaces and connections do not support distances of more than 10 meters. For these reasons, RAFI has developed the Extended Display Link gateway platform for its Glasscape touch control systems, which ensures lossless, real-time transmission of video and audio signals, user input, USB data, Internet and network protocols over distances of up to 100 meters.

The solutions are each based on a gateway module for installation in or on the application controller and a matching remote station integrated directly into the Glasscape displays. Depending on the distances to be bridged and the desired bandwidth, the gateways are available in three ascending performance classes: Short Range, Mid Range and Full Range. EDL Short Range offers an economical solution for standard applications with transmission distances of 5 to 10 meters and low signal diversity.

The series supports HDMI, DisplayPort or USB interfaces for the transmission of video, audio and control signals. For higher requirements and distances of up to 15 meters, EDL Mid Range is available, which not only transmits touch signals and high-resolution video/audio data at a data rate of up to 3 Gbit/s, but also Ethernet and USB signals as well as the embedded protocols UART, SPI or I2C Depending on the requirements, the technologies FPD Link, APIX or GMSL are used for this. While EDL Short Range and EDL Mid Range are supplied by RAFI as integrated solutions in customized form factors, the EDL Full Range gateway for transmission distances up to 100 meters is available as a remote HDBaseT standard module for stand-alone installation. This means that the devices in the 145 x 35 x 128 mm DIN rail housing ensure particularly simple and flexible installation in the target applications.

In addition to the HDBaseT interface, EDL Full Range has one HDMI, one display port, one DVI, one USB and one Ethernet interface for connection to all relevant standards. HDBaseT technology enables the gateway to achieve a data rate of up to 8 Gbit/s, for example for video transmissions with 4K resolutions. Furthermore, in addition to transmitting all media data and touch control signals, the HDBaseT standard enables the connected HMI panel to be powered via a common CAT5e cable. In addition, EDL Full Range also supports BroadR-Reach technology for on-board vehicle systems. This Ethernet-based protocol is suitable for transmitting touch, control and multimedia data with a resolution of up to 2048 x 1080 pixels. A simple twisted pair cable is sufficient as the transmission medium between the computer unit and the HMI panel.

Extended Display Link enables machine and plant manufacturers to easily standardize their HMIs for different products and to choose an extremely slim design for this purpose. In addition, manufacturers benefit from cost savings due to the elimination of CPUs and the use of standard cables, as well as from a significant reduction in their own development, maintenance and software efforts.