JAI CV-A11 operation manual Frame-delay read out Mode, Frame delay read out

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CV-A11

6.7. Frame-delay read out Mode

This mode allows simultaneous capture of multiple camera using a common external trigger pulse subsequent multiplexed (sequential) readout using a single input frame grabber, as the user has control over when the image is read out from the CCD sensor. The exposure starts at the falling edge of the ext. trigger signal, and ends at the rising edge of the ext. trigger signal (in the same way as Pulse Width Control mode). The captured image is now stored in the CCD until an ext. VD signal is given to the camera. The effective video signal is output 14H after the falling edge of WEN signal.

To use this mode:

 

 

Set function:

Trigger mode to “Frame Delay Readout”

TR=3

 

HD accumulation

HC=0, HC=1

 

Polarity and other functions

 

Input:

Ext. trigger to pin 5 on 6 pin connector (or 11 on 12 pin connector)

 

Ext. VD to pin 7 on 12 pin connector.

 

 

Ext. HD to pin 6 on 12 pin connector. (If used).

 

Fig. 19. Frame delay read out

Important notes on using this mode:-

The readout delay time must not exceed 2 seconds. This is because visible dark current noise may appear on the video signal due to the long time exposure of the CCD image sensor.

This trigger mode is also supported by a function called “HD Asynchronous Accumulation”, ACSII command “HC”. This function allows integration to start immediately at the leading (falling) edge of the Ext. Trig pulse instead of at the next horizontal drive pulse HD. Please refer to fig. 15 and fig. 16. To enable this function, set HC=1. (Factory default is HC=0). If the falling edge of the trigger falls inside the HD low pulse, a jitter up to 7.5sec. can be expected. The exposure will start up to 7.5sec. after the falling edge of the trigger.

In HD asynchronous Frame-delay mode avoid the trigger to raise inside the HD low period. It will cause 1 line image position jitter.

As the start of exposure will be synchronized with the internal H signal, the start of exposure may be shifted by max 1H. To avoid this shift (jitter), synchronize the camera with an external HD and make sure that the trigger pulse aligns to the HD signal as shown in Fig. 14.

It is recommended to use a strobe light (e.g. LEDs or Xenon tube), as the CCD must not be illuminated during readout delay time. The EEN signal can be used to trigger a strobe light

See Fig. 11 for the phase relationship between ext. HD and ext. VD pulses.

Do not input a new trigger before the previous video is read out. (WEN is high).

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Contents CV-A11 Table of Contents CV-A11Main Features GeneralStandard Composition Camera Housing and Dimensions Pin Multi-connector DC-IN/VIDEO OUT, EXT.HD/VD Pin Multi-connector Trigger and RS232CPin Assignment Input and Output Circuits Video outputTrigger input HD and VD inputFunctions and Operations Basic functionsInput-output of HD/VD Signals Continuous Operation Non triggeredExternal Trigger Modes Edge Pre-select Mode.TR=1Edge Pre-select Mode Important notes on using this modePulse Width Control Mode Pulse width controlFrame-delay read out Mode Frame delay read outLong Time Exposure Mode Long time exposureStart/Stop Mode Start/stop modeSmearless Mode Smearless modePartial scan readout mode Readout format Frame rate Effective linesOther Functions Configuring the Camera RS-232C controlCV-A11 RS-232C command list Useful commandsCamera Control Tool for CV-A11 Internal Switch and Jumper Settings Selecting termination of HD/VD input signals1. HD/VD input-output selection Specifications Spectral SensitivityWEN out on pin 6 on 6 pin connector AppendixCV-A11 emulating CV-M10 interfacing Precautions Typical CCD CharacteristicsUsers Record Camera type CV-A11 Revision Revision a Serial No ……………