There are many types of Ethernet cameras available for machine vision applications. This is a brief introduction to Ethernet and why 10GigE cameras are attractive.
Project requirements need to be determined prior to selecting the right camera for a machine vision application. A prior blog post, How to Choose the Best Camera for your Machine Vision Application, outlines the basic questions that should be answered to help you determine which camera to use. Some important considerations are the camera bandwidth requirements, distance to the computer, and, of course, cost.
Bandwidth is dictated by data flow or bits per second. And, there is a limit to how far this data can travel over copper wire before the peak to peak square wave voltage signals that constitute the image data become too degraded to be recognized at the computer. So, cable length can be an important consideration. It doesn’t take long to route more than 10m around a complicated machine and to a computer.
So, Ethernet is evolving. It began years ago as a very good way to transmit digital data over inexpensive copper multi-conductor cable and was intended for the general IT, Information Technology Industry. Original Ethernet could handle 10Mb/s data speed. Then Fast Ethernet was developed and allowed 100Mb/s. Now we have Gigabit Ethernet, 10GigE and many others. It is more convenient to refer to these all as NBASE-T Ethernet protocols. Here is a convenient table from Wikipedia illustrating this.
The above Standard terms are classifications used within the IT world. In the machine vision industry we are accustomed to say Ethernet, GigE and now 10GigE. However, you will start hearing more camera manufacturers stating they will be offering NBASE-T cameras. These will be cameras that are 2.5G or 5G Ethernet cameras. Why bother offering 2.5GBASE-T or 5GBASE-T cameras? Why not go straight to 10GBASE-T or 10 GigE cameras? One reason is that there are a lot of applications that currently have Cat 5e wires employed and these 2.5G and 5G cameras could be used without changing wires. That can be a real cost savings. And, since most of the chip development for these circuits are being developed by IT manufacturers then camera manufacturers can piggy back on that development and employ those same semiconductor devices.
You can see that the 25GBASE-T and the 40GBASE-T technologies require a cat 8 cable and can only yield maximum bandwidths over 30m of cable rather than 100 meters. That is a significant limitation and thus is not being seriously considered by camera manufacturers. However, 10GigE cameras use commonly found cat 6 cables and can provide excellent performance at the 100m length. Also, there are numerous 10GigE network interface cards, NICs, available. And, they are less expensive than the high bandwidth frame grabbers needed by other cameras that are high bandwith, such as CoaXPress and Camera Link HS.
Let’s take a look at one manufacturer’s 10GigE camera and consider it’s specifications. I’m going to highlight the VRmagic RIC10 camera. This camera has the following basic features:
- supports 2.5, 5 and 10 Gigabit Ethernet.
- supports global shutter sensors ranging from a 2.2 MP CMOSIS @ 338 fps to a 12 MP Sony Pregius @ 64 fps in color, monochrome or multispectral.
- GigE Vision software is hardware agnostic so this camera will work with any existing software designed for GigE Vision.
- reduced region of interest allows 1,000 fps on a 2,048 x 340 pixel.
- standard C-Mount Lens format.
- available with full IP65/67 protection, M12 connectors, and opto-isolated I/O.
- inexpensive NASE-T NIC are available starting around $120 USD.
So, what are the primary reasons to select a 10GigE camera for an application? They are:
- Same camera for future needs. So, as the application’s required bandwidth increases over time this same camera can be used since it will output GigE, 2.5, 5 and 10GigE data rates.
- Inexpensive NIC card used rather than more expensive frame grabber.
- No significant change in software since GigE Vision works with all ethernet standards.
- Maximum length of 100 meters allowed.
- Basic Ethernet cables can be purchased in bulk and cut to length, resulting in more cost reduction.
Want to see more about the RIC10 GigE camera from VRmagic then click here.
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