Asynchronous Reset Cameras

This section helps the MultiCam user to select the appropriate template for interfacing an analog progressive asynchronous reset camera to a Domino board.

The majority of cameras used for industrial applications are progressive-scan cameras operating in the asynchronous reset mode. The camera operates in the frame on-demand mode: it delivers an image frame on request when the application requires it.

On Domino frame grabbers, the frame grabber issue a "Reset" signal towards the camera to initiate the exposure phase of the image capture sequence. The "Reset" signal is sent by the frame grabber as a response to a "hardware trigger" originating from the system hardware or a "software trigger" originating from the application software running on the PC hosting the Domino board.

The duration of the exposure can be controlled by the frame grabber or by the camera.

When the exposure time of the camera can be controlled by the frame grabber using the pulse width of the "Reset" signal, it is recommended to select a "GrabberExposeAR" camera model. With that model, the exposure time is fully controlled by the Channel parameters of the Exposure Control category.

If the selection of the GrabberExposeAR is not possible, use instead the "CameraExposeAR" camera model. In that case, the exposure time needs to be defined by a camera setting. Furthermore, if a strobe output is also needed, it is necessary to copy the value of the exposure setting of the camera into the Channel parameter TrueExp_us in order to have the appropriate timing for the Strobe pulse produced by the Domino board.

For both Asynchronous reset camera models, there are five options for the synchronization scheme:

CamConfig	Hor. SyncMode (Signal)	Hor. SyncRef	Vert. SyncMode	Vert. SyncRef
PxxRA	Analog (Video)	Camera	Analog (Video)	Camera
PxxRA_D	Analog (Video)	Camera	Digital (Vsync)	Camera
PxxRD	Digital (Hsync, Pclk*)	Camera	Digital (Vsync)	Camera
PxxRM_A	Master(Hdrive)	Frame grabber	Analog (Video)	Camera
PxxRM_D	Master(Hdrive)	Frame grabber	Digital (Vsync)	Camera

The recommended synchronization scheme corresponds to the CamConfig value PxxRA_D. In that case, the frame grabber synchronizes horizontally using the sync signal embedded in the video; it synchronizes vertically using a digital vertical sync signal that is produced by the camera at the beginning of every valid. Such vertical sync signal is named Vsync in MultiCam and is often named "WEN" in the camera documentation manuals. The mode is applicable only if the following requirements are fulfilled by the camera:

The camera permanently sends horizontal synchronization embedded in the analog video signal applied to the video lane 1 of the MultiCam channel. (For RGB cameras, a sync on Green is required)
The camera generates one Vsync pulse at each valid frame. It may not generate additional Vsync pulses.

If PxxRA_D is not possible because the Vsync pulse is not available or inadequate, consider PxxRA. In that case, the vertical synchronization uses a composite sync embedded in the analog video. The mode is applicable only if the following requirements are fulfilled by the camera:

The camera permanently sends horizontal synchronization embedded in the analog video signal applied to the video lane 1 of the MultiCam channel. (For RGB cameras, a sync on Green is required)
The camera generates a valid composite sync (PAL 555 or NTSC 666 pattern) prior to each valid frame. The video signal may not contain other composite sync in the interval between the end of exposure and the effective begin of the readout.

For cameras requiring an Horizontal drive signal from the frame grabber, consider PxxRM_A and PxxRM_D. They have similar requirements than PxxRA and PxxRA_D for the vertical synchronization.

The PxxRD mode implements digital horizontal synchronization. It has the same requirements as PxxRA_D and PxxRM_D for the vertical synchronization. This mode requires the following digital synchronization signals, in addition to the Reset and analog video signals:

1 Pixel Clock signal (only when used with Domino Alpha 2 and Domino Iota)
1 Digital Horizontal Sync
1 Digital Vertical Sync

Domino D³ boards don't require the pixel clock.