How do you think the new GigE standards will influence the machine vision industry?
Respond or ask your question now!
Camera Link Products
by Rich Handley
It became apparent to many, in late 2000, that customers were having problems interfacing cameras and frame grabbers. Soon after PULNiX released its TMC-6700 and TMC-1000 cameras, others began expressing interest in Channel Link, the digital transmission method used in those cameras. A committee of industrial camera and frame grabber manufacturers investigated the feasibility of adopting Camera Link as an industry-wide standard, an idea which was well-received (though still has not been adhered to universally). The Camera Link specification defines a standard connector on both camera and frame grabber; a standard cable connecting the two; formats for transmitting image data from camera to grabber; four standard camera control inputs; a standard method for transmitting serial communication data between them; and a standard chip set used in both camera and grabber for image data transfer.
Camera Link is based on the new Channel Link LVDS (Low Voltage Differential Signaling) chip set manufactured by National Semiconductor. LVDS, the most common means to transmit digital data in recent years, has several major drawbacks, however. First, it requires a pair of wires for transmission of each data bit, creating bulky cables prone to breakage if stressed. Also, the maximum data transmission rate of LVDS is 400 MB/s, fast enough for today's applications, but limiting for tomorrow's requirements.
Channel Link technology offers many advantages over the RS-644 LVDS technology that pre-dated it. Channel Link can transfer 28 bits of data over just four pairs of wires, with a fifth pair used to transfer a required clock signal. This compares very favorably with the 56 wires needed with RS-644 LVDS for the same job, and Camera Link is capable of much higher data rates than standard LVDS. A single chipset can transfer up to 2.38 Gbits/sec, and the Camera Link standard allows the use of up to two chip sets. This high bandwidth capability is more than enough for current needs and allows for future expansion. The following are just a sampling of the many cameras and frame grabbers to adapt the Camera Link standard......