8.Features
© China Daheng Group, Inc. Beijing Image Vision Technology Branch 99
The time of packet delay is:
𝑇
𝑑𝑒𝑙𝑎𝑦
= 2000 125,000,000
⁄
= 16𝜇𝑠
The effective network bandwidth is:
Band𝑊
𝑎𝑣𝑖𝑎𝑙
= (8156 × 8 × (1 − 0.2))/(66𝜇𝑠 + 16𝜇𝑠) = 637𝑀𝑏𝑝𝑠
8.5.4. Bandwidth Reserve
The Bandwidth Reserve is used to reserve a part of bandwidth for packet retransmission and control data
transfer between the camera and the host, and can be used for multiple cameras transmission, to limit the
bandwidth allocation of each camera. For example, the network bandwidth is 1Gbps, setting the reserved
bandwidth value to 20%, then the bandwidth will be reserved to 0.2Gbps. When the maximum bandwidth
required for transmission is greater than the current bandwidth available, the camera reduces the frame
rate to ensure the stability of the transmission
8.5.5. Frame Transfer Control
When multiple cameras are connected to the host by switches, if trigger these cameras to acquire images
at the same time, when transmitting the images, because of the instantaneous bandwidth of the switch is
too large, and the storage capacity is limited, data loss will occur. Therefore, the user needs to use frame
transfer delay to avoid this problem.
In trigger mode, by setting the Transfer Control Mode as "User Controlled", when the camera receives
software trigger command or hardware trigger signal and completes the image acquisition, the camera will
save the images in the frame buffer which is internal the camera, waiting for the host to send the
"Acquisition Start" command, the camera will transmit the images to the host. The transmission delay time
is determined by the host. When multiple cameras are triggered simultaneously, different transmission
delay can be set for each camera to avoid the instantaneous bandwidth of the switch is too large.
The Frame Transfer Control function is valid only in trigger mode.
8.6. Events
When event notification is set to "on", the camera can generate an "event" and transmit a related event
message to the host whenever a specific situation has occurred. For MARS-G-P series camera, the
camera can generate and transmit events for the following situations:
The camera has ended exposure (ExposureEnd)
An image block is discarded (BlockDiscard)
The trigger signal overflow (FrameStartOvertrigger)
The image frame block is not empty (BlockNotEmpty)
The event queue is overflow (EventOverrun)
The burst trigger signal overflow (FrameBurstStartOvertrigger), (only for MARS-3140-3GM/C-P)
