GigE camera connection and configuration

• GigE camera connection options
• Configuration and connection to Cognex Designer project

GigE is a standardized interface for transmitting video data and related data over Ethernet. This means that the camera has a standard RE45 Ethernet port and connects via standard network elements.

The camera also requires power, and if we were to connect the camera directly to the computer’s onboard network card, we would need to connect it separately to a power source using this IO+power connector.

However, these cameras often have the option of POE (Power over Ethernet) power supply, which means they can be powered directly through the Ethernet cable if connected to a port that supports POE. Standard onboard network cards do not typically support POE.

It is ideal when the card also has a dedicated communication channel with the computer, dedicated network port, so that the reception of images from this camera is not affected by other communication.

Since we almost always connect multiple cameras to a PC, we use a CFG-8724 network card with four ports and POE support. This card is designed for such applications.

This card uses a PCIe x4 interface, which means you need at least one PCIe x4 or PCIe x8 or PCIe x16 slot in your computer. Later on, we will also see that for communication with peripheral devices (such as PLC or lighting), we almost always use a communication card called CIO-CC24, which has a PCIe x1 interface. Therefore, a computer used for full-fledged work with Designer should have an additional slot, at least x1, x4, x8, or x16.

To connect this card, you simply insert it into the slot, and it should fit without much force. Although I know that most of you already know how to do this, I have encountered people who haven’t done it before, so I prefer to show it here. Sometimes you need to prepare an opening in the part where you will insert the card—on some casings, you may need to remove a piece of metal, while others require unscrewing, and some casings have a separate mechanism that speeds up the process. When installing, pay attention to ensure that the card is correctly aligned.

The slot itself may not securely hold the card, so after inserting it, you need to secure it by screwing it in along the edge. Usually, there are threaded holes in place for this purpose, and sometimes screws are supplied with the PC casing.

You may have noticed that the card also has a connector for additional power. Since most camerasdoes not require  more than 4 watts, it is not necessary to connect this connector because PCIe x4 should be able to deliver 25W, and PCIe x16 can deliver around 75W. In this Nuvo PC, we have only one such connector on the board, and we can save it for a potential graphics card if we plan to use neural networks, for example, in the project. But from experience we have found it is more reliable when you connect the additional power cable to the card.

Then we connect the cameras individually using an Ethernet cable directly to this Ethernet card. During testing, any Ethernet cable may be sufficient, but on the production line, we always use a cable with a connector with a horizontal screws on one end, allowing us to screw it securely to the camera. From experience, this is a much more reliable solution.

If we know that the camera will be completely static on the line, then a cable from Basler labeled 10170259 for 5m, 10170260 for 10m, or 10170261 for 20m is sufficient. Alternatively, we can use the Cognex CGE-CBL-FLEX-H-xM cable, where x can be 5, 10, or 20 meters. These are the same cables from Basler, but from Cognex, we can have them much faster if needed.

However, if it is expected that the camera will be connected to any form of movement, even minor, it is automatically necessary to use L-Com cables labeled TRG514-T6T-xM, where x indicates 1, 2, 3, 5, or 10 meters.

We have tried other flex cables, but they did not prove to be reliable, and we often had more issues with them than benefits.

When installing on the line, it is advisable to label both the camera and the cable, and ideally, the Ethernet port used as well. In case of any rewiring or moving the computer, it is easier to reconnect the cameras to the original ports rather than reconfiguring camera settings in the software.

As I mentioned before, we try to connect the cameras to separate ports to avoid interference with other communication. However, we often need to connect more than four cameras. The standard license from Cognex allows using eight cameras, but there is also an option to purchase an extension for an unlimited number of cameras. What if we exceed that? If the computer allows it, we try to connect an adequate number of such GigE cards.

If not, then we use POE switches and dimension them based on the estimated load. For example, we also use 10-port POE switches like the Netgear MS510TXPP, where we can directly connect 8 cameras to 1Gb, 2.5Gb, or 5Gb interfaces, and each camera can be up to 100m away from the switch if we use at least Cat5e cable.

We connect these switches to the PC via a 10G link, either metallic or optical. The maximum distance with copper twisted pair Cat6 cable is 30m, and with Cat6A, you can go up to 100m. If you use a weaker cable for a longer distance, it will still work, but the transmission speed will be automatically reduced.

Distances of up to 2 kilometers can be achieved using the 10GBASE-X SFP+ optical interface of this switch, of course, in combination with a suitable module and a PCIe card in the PC that supports such an interface.

As I mentioned, the camera has a standard Ethernet port, and if you need to connect it, for example, to a laptop and you don’t have a POE switch or a suitable power IO cable and source for it, you can use a POE injector. You connect the laptop or switch to one socket of the injector, and in the other socket, which is powered and supports POE, you connect the camera.

Let’s move on to the configuration on the PC:

• Run GigE configurator, either through Start or through Designer.
• Configure each network interface to have its own subnet.
• Configure Jumbo Packets.
• Configure the firewall.
• Connect to the project and set the latency level.

We will cover how to set the internal parameters of the camera and how to address specific issues with GigE and camera imaging in separate sections later on.