53
Alvium USB Cameras User Guide V3.6.4
Specifications
• If the trigger controlled exposure time does not match the available increment,
the camera automatically extends the exposure time to the next increment.
• Subsequently, the
exposure time offset is added
.
You can use
ExposureActive
to determine the duration of the exposure time
offset.
Operation for maximum frame rates
Values for maximum frame rates and for minimum and maximum exposure time in
the specification tables are based on following parameters:
• Factory settings (camera after startup)
• Minimum exposure time
• Full resolution
• Mono8 pixel format or 8-Bit Bayer pixel format
• Camera operation in freerun mode
• Minimum value for
SensorBitDepth
(8-bit sensor ADC readout mode if
available)
• Bandwidth required for the corresponding frame rate, as stated in the tables
for ROI frame rates.
Bandwidth
: Data is provided for 200 MBps, 375 MBps, and 450 MBps, using 8-bit,
10-bit, and 12-bit sensor ADC readout modes, depending on model abilities. The
default value for
DeviceLinkThroughputLimit
is 200 MBps for Alvium 1800 U
cameras measured as average sensor readout.
Frame rates with rolling shutter sensors
The following table shows how the shutter mode impacts available frame rates.
Reducing the area for ROI reduces readout time. The relations in
only if exposure time is shorter than readout time.
Sensor type
Shutter mode
Trigger mode
Available frame rates ROI frame rates
Global shutter (GS)
Global shutter (GS)
Freerun
Maximum values
Increased values
Global shutter (GS)
External trigger Maximum values
Increased values
Rolling shutter (RS)
Rolling shutter (RS)
Freerun
Maximum values
Increased values
Rolling shutter (RS)
External trigger
Halved values
Increased values
Global reset shutter (GRS) Freerun
Maximum values
No increase
Global reset shutter (GRS) External trigger Maximum values
No increase
Table 15: Frame rates depending on shutter modes and trigger modes
