Measurement Computing TempScan/1100 - Manual (Page 102)

5-12 System Operation 889897 TempScan / MultiScan User's Manual
Buffer Overrun With Multiple Trigger Blocks
When more than one Trigger Block is in the Acquisition Buffer, a buffer overrun will erase the oldest
complete Trigger Block. If the Trigger Block being erased is currently being read, that Trigger Block read
will be terminated and the Read Pointer will be advanced to the start of the next Trigger Block.
If the controller detects a buffer overrun condition during a read operation, any further reading will be
considered corrupt until a buffer reset is issued. This buffer reset can be done via the Flush Acquisition
Buffer (
*B
) command or reading the remaining data out of the buffer until it is clear.
Buffer Buffer
Read Pointer > Scan -50 Pre-Trigger
Scans
Scan 751 Post-Stop
Scans
Scan -49 Write Pointer > Scan 752
Scan -48 N/A
… N/A
Scan 000 Post-Trigger
Scans
No longer
accessible
Scan 000 Post-Trigger
Scans
… …
Scan 252 Read Pointer > Scan 252
… …
Write Pointer > Scan 450 Scan 450
… …
N/A Scan 500
… Post-Stop
Scans
… Post-Stop
Scans
End of Buffer > N/A End of Buffer > Scan 750
(1) The Write Pointer advances as scans are
collected while the Read Pointer advances
as scans are read from the buffer.
(2) After 302 scans, the Read Pointer has
advanced to Scan 252 while the Write Pointer has
advanced to Scan 752 (returning to the start of the
buffer and erasing the entire Pre-Trigger area).
Buffer Overrun – Single Trigger Block With Pre-Trigger Area
Buffer Buffer
Scan 000 Post-Trigger
Scans
Scan 601 Post-Stop
Scans
Scan 001 Write Pointer > Scan 602
Read Pointer > Scan 002 No longer
accessible
Scan 002 Post-Trigger
Scans
… …
Scan 252 Read Pointer > Scan 252
… …
Write Pointer > Scan 352 Scan 352
… …
N/A Scan 450
… Post-Stop
Scans
… Post-Stop
Scans
End of Buffer > N/A End of Buffer > Scan 600
(1) The Write Pointer advances as scans are
collected while the Read Pointer advances
as scans are read from the buffer.
(2) After 250 scans, the Read Pointer has
advanced to Scan 252 while the Write Pointer has
advanced to Scan 602 (returning to the start of the
buffer and erasing one Post-Trigger scan at a
time).
Buffer Overrun – Single Trigger Block Without Pre-Trigger Area