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CM-030GE/CM-030GE-RA / CB-030GE/CB-030GE-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 equations show the relationship between the PE value used by the camera for the
different readout modes and the "Exposure Time Abs" 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 -43) µs / (864
(2)
/40000000
(3)
)
V Binning readout PE= 2 + INT (Exposure time -46) µs / (936/40000000)
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
43 us
11,038 us 511L
2/3 Partial Scan
43 us
7,733 us 358L
1/2 Partial Scan
43 us
6,221 us 288L
1/4 Partial Scan
43 us
3,867 us 179L
1/8 Partial Scan
43 us
2,722 us 126L
V-Binning Scan
46 us
6,013 us 257L
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.
As for the setting example, refer to chapter 6.5.1.
9.3. Auto-detect LVAL-sync / a-sync. 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 /a-sync accumulation