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Trigger over Ethernet versus other trigger modes

Trigger over Ethernet (ToE) is available in certain camera models now – is it right for me? It’s yet another tool in the toolbox, and we’ll try to put it in context amongst diverse triggering options.

Before considering triggering, let’s take a moment to consider just what needs to be triggered. Ultimately, it’s a camera from which you wish to generate an image, with some degree of precision about when the image is acquired. In the simplest case, it’s just a single camera, with no other devices.   

Sometimes the camera and a strobe light must be synchronized to work together. In complex applications, perhaps there are two or more cameras, which must acquire images simultaneously, or in some defined cascade relationship to align with the physical events they must capture.

 

 

Comparing Trigger Modes

Trigger modeSingle cameraWith two or more cameras
Trigger over Ethernet (ToE) Action Commands
  • Computer program sends trigger command over Ethernet
  • No extra wiring required; PoE cameras allow single cable solution.
  • Lag (PC-->Exposure): ~ 125 μs
  • Usage note: Ideal for program-driven triggering
  • Computer program sends trigger command over Ethernet
  • No extra wiring required; PoE cameras allow single cable per camera solution.
  • Lag (PC-->Exposure): ~ 125 μs
  • Usage note: Ideal for program-driven triggering
Freerun
  •  Images generated as fast as sensor exposure permits
  • Easiest configuration (none), but not correlated to anything in real world
  •  Images generated as fast as sensor exposure permits
  • Easiest configuration (none), but not correlated to anything in real world (nor the other camera(s))
IEEE 1588 Precision Time Protocol (PTP)
  • Not applicable except/unless to synch the camera to a GPS real-time clock if desired
  • Synchronizes two or more cameras to a shared heartbeat
  • Optionally synchronize to a GPS clock if desired
  • Accuracy: < 2 μs variance
  • Usage note: Shared heartbeat, not a true “trigger” as such
 
External (hardware) trigger
  • Actuator such as motion or light detector generates trigger signal
  • TTL trigger: <5 μs
  • Optocoupled trigger:  ~ 25 μs
  • Requires additional wiring
  • Usage note: Ideal for actuator-driven applications

 

  • Second/nth camera can be “slave” from master, or “gang” (shared) trigger
  • TTL trigger: <5 μs
  • Optocoupled trigger:  ~ 25 μs
  • Requires additional wiring
  • Usage note: Ideal for actuator-driven applications
 

Learn more about trigger modes

Learn more about Trigger over Ethernet’s benefits, options, and advanced scenarios by downloading our dedicated application note today.

Still wondering which triggering mode is best for your application and/or what are the best components and architecture overall?  Get in touch with us today and we’ll be happy to answer your questions.

 

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