JAI CB-200GE, Руководство пользователя

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CM-200GE/CM-200GE-RA/CB-200GE/CB-200GE-RA
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Exposure Time Abs (GenICam Standard)
This is a function specified in the GenICam standard.
The shutter speed can be entered as an absolute exposure time in microseconds (μs) in register
address 0xA018. The entered absolute time (Time Abs) is then converted to programmable
exposure (PE) value inside the camera.
The below calculating formula shows the relationship between the PE value used by the camera
for the different readout modes and the value entered in register 0xA018.
As the calculation is based on rounding down to the closest integer, precise values may not always
occur.
The relation between PE value and Time Abs:
Normal readout PE= 2 + INT
(1)
(Exposure time -64) µs / (2080
(2)
/65000000
(3)
)
V Binning readout PE= 2 + INT (Exposure time -71.692) µs / (2330/65000000)
Note: (1) INT means integer (rounded down). (2) Pixel clocks/line. (3) Pixel clock
The following table shows minimum value and maximum value for each readout mode.
Minimum value Maximum Value
Normal Scan 64 us 40,032 μs
2/3 Partial Scan 64 us 28,512 μs
1/2 Partial Scan 64 us 22,816 μs
1/4 Partial Scan 64 us 14,386 μs
1/8 Partial Scan 64 us 10,208 μs
V-Binning Scan 71.692 us 22,476 μs
GPIO in combination with Pulse Width trigger
More precise exposure time can be obtained by using GPIO in combination with Pulse Width trigger
mode. The clock generator and counter can be programmed in very fine increments.
For examples of settings, refer to chapter 6.5.1.
9.3. Auto-detect LVAL-sync / async. accumulation
This function replaces the manual setting found in older JAI cameras. Whether accumulation is
synchronous or a-synchronous in relationship to LVAL depends on the timing of the trigger input.
When trigger is received while FVAL is high (during readout), the camera works in LVAL-
synchronous mode, preventing reset feed trough in the video signal. There is a maximum jitter of
one LVAL period from issuing a trigger and accumulation start.
If trigger is received when FVAL is low, the cameras works in LVAL-asynchronous mode (no delay)
mode. This applies to both pre-select (PS) trigger mode and pulse width trigger (PW) mode.
Ext. trigger
FVAL
(1) (3)
(1) In this period camera executes trigger at next LVAL (prevents feed-through noise)
(2) Avoid trigger at FVAL transition (+/- 1 LVAL period), as the function may randomly switch
between "next LVAL" and "immediate".
(3) In this period camera executes trigger immediately (no delay)
(2)
Fig. 27. Auto-detect LVAL sync /async accumulation