Basler A302f User Manual

Contents

Basler A302f User Manual Manual pdf 24 page image

Operation and Features3-8 BASLER A302fDRAFT3.3 Trigger Ready SignalOne possible way to control the camera is to perform an image exposure followed by charge readout and frame transfer and to wait until frame transfer is complete before beginning the nextexposure. This situation is illustrated in Figure 3-5.Figure 3-5: Exposure Between Frame TransfersWhile the method of control shown above may be useful in many situations, it is not workable ifyour objective is to achieve maximum frame rate. To achieve maximum frame rate, most of theexposure for each frame must take place while the previous frame is being transferred out of theCCD array. This situation is illustrated in Figure 3-6.Figure 3-6: Exposure During Frame TransferA point to notice when looking at Figure 3-6 is that exposure must not end during frame transfer;the end of exposure for the next frame must occur at least 100 ns after the transfer of the currentframe. (For example, the exposure for frame two must end at least 100 ns after frame one transferis complete.)This situation poses a problem when you are controlling exposure with an ExTrig signal, that is,how will you know when to toggle the ExTrig signal and begin exposure so that the exposure willend at least 100 ns after the last frame transfer.This problem is addressed by the trigger ready signal. The trigger ready signal will go high at theearliest moment that you can begin exposure and still be sure that the exposure will end at least100 ns after the transfer of the last frame.* The trigger ready signal is not defined in the 1394 Trade Association Digital CameraSpecification. Trigger ready is a special feature of Basler cameras.Frame 1 Transfer Frame 2 Transfer Frame 3 TransferFrame 1ExposureFrame 2ExposureFrame 3ExposureReadOut ReadOut ReadOutFrame 1 Transfer Frame 2 Transfer Frame 3 TransferFrame 1ExposureFrame 2ExposureFrame 3ExposureFrame 4Exposure> 100 ns > 100 ns > 100 nsReadOutReadOutReadOutReadOut