New-Tech Europe Magazine | July 2019 | Digital Edition

Fast Running 5GBASE-T Cameras Recognizing these benefits, a number of companies have now introduced both line scan and area array-based cameras based on the 5GBASE-T standard. One example of such an area array camera is LUCID’s Atlas ATL314S 5GBASE-T camera featuring the large format 31.4MP IMX342 CMOS sensor from Sony. With an M12 Ethernet connector capable of transferring up to 25.50 w (PoE+, Type 2) and 5Gbit/s of data, the camera can operate at a resolution of 6464 x 4852 with frame transfer rates of 17 fps at distances of 100m over CAT 6 cable. Not Just About Speed There are many reasons why manufacturers of machine vision cameras have embraced the 5GBASE-T standard. Just as Camera Link Extended Full version runs at a maximum of 6.8 Gbits/s over distances of 5m, the USB 3.1 and USB 3.2 interfaces (although they can transfer data at up to 10 Gbits/s and 20 Gbits/s respectively) are limited to camera-to-computer connection distances of 5m (USB 3.1) and 3m (USB 3.2). Similarly, the fastest camera-to-computer interface, CoaXPress (CXP) can transfer data at speeds as high as 12.5 Gbits/s per CXP link, and thus 50 Gbits/s using four links. Cable length is limited to a maximum of 35m at these data rates; however, if using slower data links of 3.125 Gbits/s, cables can be extended to 100m. Like Camera Link, a relatively expensive (+$2500) PCIe frame grabber is required to implement CXP-based systems. Some high-speed line-scan applications (such as web inspection) demand low latency, low-jitter, point- to-point interfaces, therefore CXP systems must be deployed.

Figure 1: 10GBASE-T has a Nyquist frequency of 400 MHz, i.e. most transmitted data is contained below this frequency. Reducing the speed to 5 Gbps (5GBASE-T) reduces the Nyquist frequency to 200 MHz, thus falling within Category 6 cable’s specified bandwidth. Reducing the speed to 2.5 Gbps (2.5GBASE-T) reduces the Nyquist again by half to 100 MHz, within the specified bandwidth of Category 5e cable.

Figure 2: Examining the installed Ethernet outlets by cable type shows that cur- rently CAT 5e and CAT 6 cabling dominates the market while CAT 6a and CAT 7 cabling is only just starting to emerge to support higher data rates. The low-cost CAT 6 cable is one reason why camera vendors have adopted 5GBASE-T, a standard that operates at 5Gbits/s at distances of 100m over CAT 6 cable.

Figure 3: Atlas 5Gige Camera - The Atlas camera with Sony Pregius Sensors over 5GBASE-T PoE. GigE Vision and GenICam compliant camera capable of 600MB/s data transfer rates (5Gps), allowing for high resolution and high frame rate over standard copper ethernet cables up to 100m.

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