40 
   C2 Series User Manual Rev. 1.9 
The C2 Series Chunk Data Mode 
General Description 
 
The C2 series features a Chunk Data mode for providing additional information to the acquired image 
data. The implementation of XML nodes is performed according to SFNC 1.4: 
  Category ChunkDataControl 
  ChunkModeActive 
  ChunkModeSelector (OneChunkPerFrame, OneChunkPerProfile) 
The ChunkData generated by the camera have the following format: 
  ChunkImage 
  1…N x ChunkAcqInfo 
  ChunkImageInfo 
Depending on camera mode (image or 3D) the ChunkData block („ChunkAcqInfo“) can be sent as 
follows: 
  In image mode, the camera can send only one ChunkAcqInfo block per image frame. 
  In  3D  mode,  the  camera  can  send  one  ChunkAcqInfo  block  either  per  3D  frame 
(“OneChunkPerFrame”) or per 3D profile (“OneChunkPerProfile”). 
The „ChunkImageInfo“ is the last ChunkData sent by the camera and contains following data: 
  Number of valid rows in ChunkImage 
  Number of valid ChunkAcqInfo blocks 
  Flags identifying the current frame as „Start“ or „Stop“ and the buffer status in AutoStart mode 
The ChunkAcqInfo block consists of totally 32 bytes containing following data 
  64 bit timestamp  
  32 bit frame counter  
  32 bit trigger coordinate 
  8 bit Trigger status 
  32 bit I/O Status 
  72 bit AOI information 
 
The data of timestamp, frame counter, trigger coordinate, trigger status and I/O status are assigned 
at the start of every image integration. 
When  ChunkMode  is  disabled, the camera  uses  the  “regular“ GEV  image  protocol,  in  which  the 
optional transfer of frames with variable height and payload is supported. 
Furthermore,  when  ChunkMode  is  enabled,  the  camera  sends  the  full  payload,  even  if  the 
ChunkImage or ChunkAcqInfo blocks contain partially valid data. The number of valid ChunkImage 
rows and ChunkAcqInfo blocks can be read from ChunkImageInfo.