Table of Contents
Advertisement
8.Features
Note: Each stream packet contains 36 bytes of network header data, and a packet with the size of 1500
bytes contains only 1464 bytes of valid data.
Example 2: The packet size is 8192, the packet delay is 2000, the reserved bandwidth is 20%, and the
link speed is 1Gbps.
The time to transport a single stream packet is:
T
μs
= (8192 × 8 ) ⁄ 10 00,000,000 = 66
d a t a
The time of packet delay is:
T
μs
= 2000 ⁄ 125,00 0,000 = 16
d e l a y
The effective network bandwidth is:
Band
W
= (8156 × 8 × (1 -0.2 )) ⁄ (66
μs
+ 16
μs
) = 637
Mbps
a v i a l
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 5Gbps, setting the reserved
bandwidth value to 20%, then the bandwidth will be reserved to 1Gbps. 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 transmission delay 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 MER-G-P/MER-G series camera, the
camera can generate and transmit events for the following types of situations:
The camera has ended exposure (ExposureEnd)
© 2023 China Daheng Group, Inc. Beijing Image Vision Technology Branch
167
Advertisement
Table of Contents
