MDR vs. SDR Cable Assemblies: Key Differences and Applications

Mini Delta Ribbon (MDR) and Shrunk Delta Ribbon (SDR) cable assemblies play a critical role in transmitting video signals within the Camera Link (CL) standard. These connectors share the same internal wiring, making them interchangeable in terms of functionality for Camera Link systems.

However, MDR and SDR cables are not compatible with the higher-speed Camera Link HS (CLHS) standard. CLHS uses different connectors, such as CX4 and SFP/SFP+, which are designed to handle faster data rates and more complex video transmission demands.

Camera Link Basics: The Foundation of Video Transmission

A basic Camera Link connection consists of:

• • Five low-voltage differential signal (LVDS) pairs – These transmit serialized video data and manage framing/enabling signals.

• • Two asynchronous LVDS serial channels – Used for camera communication.

• • Four LVDS discrete control signals – Enable additional functionality for machine vision applications.

The Camera Link chipset operates at a maximum frequency of 85 MHz. At this speed, the Base configuration (single-cable setup) achieves data transmission rates of up to 2.04 Gbps.

MDR vs. SDR: Key Differences

MDR connectors were the first to be introduced for Camera Link. SDR connectors were later developed to address space constraints in machine vision applications, offering a more compact solution while retaining Camera Link performance.

• • Size: SDR connectors are smaller than MDR connectors.

• • Data Rate: MDR connectors generally support higher data rates compared to SDR connectors.

SDR connectors are ideal for compact designs where space and weight are concerns, making them popular in industrial automation and machine vision systems.

Power over Camera Link (PoCL)

Power over Camera Link (PoCL) simplifies cable management by enabling the frame grabber to power the camera directly through the Camera Link cable. This eliminates the need for a separate power supply, reducing the overall footprint of the system.

• • Power Delivery: PoCL can provide up to 4 W (400 mA at 10 V or 333 mA at 12 V) through the Camera Link cable.

• • Pin Configuration: In the standard 26-pin CL specification, pins 1, 13, 14, and 26 serve as ground. For PoCL, pins 1 and 26 are repurposed to deliver power.

For even more compact applications, PoCL-Lite offers a smaller 14-pin solution, typically using SDR14P or SDR26P connectors.

Extending Camera Link Range

While Camera Link High Speed (CLHS) offers fiber optic options for long-distance transmission, range extenders have been developed for traditional Camera Link systems. These extenders use fiber optics to surpass the distance limitations of standard cables.

• Range:
  • Single-mode fiber: Up to 80 km.
  • Multi-mode fiber: Up to 400 m.

Range extenders address the inherent limitations of Camera Link cables, which typically max out at:

• 10 m for CL Base configurations.
• 5 m for Medium, Full, and Deca configurations at 85 MHz.
• 7 m at 66 MHz.
• 10 m at 40 MHz.

By converting signals from standard MDR cables to fiber optic links, range extenders can support PoCL on the camera side, ensuring cameras receive power over long distances.

• Bandwidth: Range extenders using SFP+ connectors can achieve up to 10 Gbps, enabling the transmission of CL Deca (80-bit) signals at 85 MHz.
• Temperature Tolerance: Some extenders are designed to operate within the full industrial temperature range of -40 to 85 °C

Conclusion

MDR and SDR connectors remain essential components in Camera Link systems, enabling efficient video transmission for machine vision and industrial automation. While SDR connectors offer space-saving benefits, MDR connectors support higher data rates. Power over Camera Link (PoCL) further simplifies design by eliminating the need for external power supplies. For longer distances, fiber optic range extenders bridge the gap, allowing Camera Link systems to operate effectively over kilometers without compromising signal integrity.