The camera is able to receive one optically isolated trigger input. The interface consists of 2 wires (Trigger-In and User-Ground). In order to initiate a trigger event, without damaging the camera, certain requirements must be met.




External Trigger Requirements:

  • The camera interface circuit limits the input current to around 5ma and also provides reverse polarity protection.
(There is no need to add any external conditioning circuitry)
  • The trigger amplitude must be greater than 5V but less than 24V. 
(Voltage differential from "Trigger-In" to "User Gnd"  5V > 24V)
  • The trigger signal must transition from low to high in order to initiate a trigger.
  • The interface supports the trigger frequency of up to 1MHZ at 50% duty cycle. 
(However the actual functional trigger frequency is limited by the cameras maximum frame rate.) 
  • A trigger/strobe cable for the LightWise Allegro Cameras can be purchased separately from ISG by request.
(http://isgcameras.com/product/u11-allegro-usb3-gige-trigger-strobe-cable/).

Acceptable trigger signal examples...

 

  1. With 0V at user ground, the minimum amplitude the trigger signal can be and still trigger the camera is 5V.
  2. With 0V at user ground, the maximum amplitude the trigger signal can be and not damage the camera is 24V.
  3. With 5V at user ground, the minimum amplitude the trigger signal can be and still trigger the camera is 10V.
  4. With 24V at user ground, the maximum amplitude the trigger signal can be and not damage the camera is 48V.



NOTE: At ISG, we use a function generator to produce the trigger signal. We typically create a square wave signal that alternates from 0V to 5V. We then vary the frequency to control the frame rate of the camera. 




Below is the pin assignment for the 12-pin connector on the back of the camera.