ST_FileRBufferHead

FileBuffer-Header-Status. This structure is used by FB_FileRingBuffer. The structure is read/stored every time the buffer is opened/closed. It is updated at each reading/writing of the data.

TYPE ST_FileRBufferHead
STRUCT
    status   : DWORD := 0; (* buffer status flags Bit 0 = 1 => Opened, Bit 0 = 0 => Closed, Bit 1 = 1 file corrupted, all other bits are reserved *)
    access   : UDINT := 0; (* access counter, increments every time the buffer is reopened *)
    nID      : UDINT := 0; (* user defined value *)
    cbBuffer : UDINT := 16#100000; (* max. buffer size (1MB) *)
    nCount   : UDINT := 0; (* number of fifo entries *)
    cbSize   : UDINT := 0; (* current (used) file buffer data byte length *)
    ptrFirst : UDINT := 0; (* seek pointer start position of first (oldest) buffer entry *)
    ptrLast  : UDINT := 0; (* seek pointer end position of last (newest) buffer entry *)
    rsrv0    : UDINT := 0; (* reserved *)
    rsrv1    : UDINT := 0; (* reserved *)
    rsrv2    : UDINT := 0; (* reserved *)
    rsrv3    : UDINT := 0; (* reserved *)
END_STRUCT
END_TYPE

status: Status flags. Bit 0 = 1 => file opened, Bit 0 = 0 => file closed. Bit 1 = 1 => file corrupted (file was closed incorrect, or max. buffer size does not match.).

acces: Access counter. Increments every time the buffer is reopened.

nID: User defined 32 bit value.

cbBuffer: Maximum buffer size.

nCount: Current number of  stored fifo entries.

cbSize: Current number of  stored data bytes.

ptrFirst: Seek pointer position of oldest buffer entry.

ptrLast: Seek pointer position of newest buffer entry.

rsrv0..rsrv3: reserved.

Requirements