Gigabit Ethernet and GigE Vision

Gigabit Ethernet (GigE) is the fastest growing interface for digital cameras in the field of industrial image processing. It is a universally applicable digital interface, which for the first time provides the potential to produce cameras that can replace analog devices in almost every application.

Gigabit Ethernet offers the widest technological flexibility with regard to bandwidth, cable length, and multi-camera functionality. It is the right choice for data rates of up to 100 MB/s and a maximum cable length of 100 meters. And it makes complex setups with several cameras very simple.

GigE cameras can use Power over Ethernet (PoE) to draw electricity via the data cable. For this to work, the setup requires a suitable Gigabit Ethernet cable. Additionally, either a special PC adapter card, or a special switch, hub or PoE injector placed between the PC and camera is necessary. The PoE setup eliminates the need for a separate power supply and cable, making installation simpler, especially in applications where space is tight. The use of one cable for power supply and data transfer also saves costs, since fewer parts need to be purchased and installed.

GigE Vision Standard

In addition to the physical interface defined by the Gigabit Ethernet standard (among others), the especially clear and logical implementation of the GigE Vision Standard supports easy integration in all image processing programs via the use of software “libraries”. Also, because the exchange of GigE Vision compatible cameras can be performed without changing the application software, new investments and follow-up costs can be estimated and well-planned with cameras based on the GigE Vision Standard.

Some of the advantages of the GigE interface are:

High data transfer rates
Uses existing Ethernet infrastructure
Long cable lengths are possible
Easy integration in all image processing applications (libraries)
High degree of standardization provided by the Gigabit Ethernet and GigE Vision standards
PoE functionality: Power supply for the camera via the data cable

GigE Vision Standard Version 2.0

The latest version of the GigE Vision standard expands the possibilities for the GigE interface. GigE Vision 2.0 allows multi-camera systems to be synchronized more precisely and/or run in real time. One important component of the GigE Vision standards in version 2.0 is the Precision Time Protocol (PTP). PTP standardizes the path - down to the nanosecond - used by components within the system to synchronize their time settings. The GigE Vision Standard 2.0 is backward-compatible, meaning that cameras running GigE Vision 2.0 will work with software and hardware designed for GigE Vision 1.2.

The key components of GigE Vision 2.0 are:

A shared, high-precision source of time for all network components through PTP (Precision Time Protocol = IEEE 1588)
Synchronous free run for the cameras
Trigger-over-Ethernet with Action Command or Scheduled Action Command, no additional I/O cable required