Basic Operation and FeaturesBasler A500k 3-1PRELIMINARY3 Basic Operation and Features3.1 Functional DescriptionBASLER A500k area scan cameras employ a CMOS-sensor chip which provides features such asa full frame shutter, electronic exposure time control and anti-blooming. Exposure time iscontrolled either internally via an internal sync signal (free-run mode) or externally via an externaltrigger (ExSync) signal. The ExSync signal facilitates periodic or non-periodic pixel readout.In any free-run mode, the camera generates its own internal control signal and the internal signalis used to control exposure and charge read out. When operating in free-run, the camera outputsframes continuously.The internally generated “effective exposure“ signal (Integrate Enabled) can be tied to theFlashOut signal (see sections 2.1.4 and 4.2.4.16).When exposure is controlled by an ExSync signal, exposure time can be either edge-controlled,level-controlled or programmable. In edge-controlled mode, charge is accumulated from the risingedge to the next rising edge of ExSync. The rising edge of ExSync also triggers the readout. Inlevel-controlled mode, charge is accumulated when the ExSync signal is low and a rising edge ofExSync triggers the readout. In programmable mode, exposure time can be programmed to apredetermined time period. In this case, exposure begins on the rising edge of ExSync andaccumulated charges are read out when the programmed exposure time ends.The A504k/kc has a special feature: In addition to sending video data to a framegrabber, it can beoutput to an VGA monitor (640 x 480 pixels). In VGA exposure mode the camera generates itsown internal control signal and the internal signal is used to control exposure and charge read out.The frame frequency is set to 60 Hz. The camera outputs frames continuously to the monitor and,at the same time, to the Camera Link output.At readout, for A500k series cameras, all accumulated charges of all pixels are simultaneouslytransported from the light-sensitive sensor elements (pixels) to the pixel memory (full frameshutter). There is a pixel memory for each pixel. As a consequence, the camera can be exposedand read out at the same time. The charges of the pixel memory are amplified. The pixel memoriescan be connected to a bus. There is one bus for each vertical column. At the end of each bus,there is an analog/digital converter (ADC).For readout, the pixel memories can be addressed linewise by closing a switch that connects thepixel memory of the addressed lines to the busses. Before the analog video data enters the ADC,the offset is added, plus a value that corrects column fixed pattern noise. The analog video datais digitized by a ten bit, Analog to Digital converter (ADC). The ADC’s reference value is used toset the gain. The digitized video data then passes a digital 128 stage shift register, which outputs10 x 10 Bit of data in parallel with each cycle. Then the 10 Bit sensor output enters the digital shifter