User`s guide

Time Capture Data
A time capture data contains long streams of raw time data captured by an instrument. The files contains
some or all of the following results.
Time Data
Time data is identified in a time capture file with the following SDF_DATA_HDR attributes:
dataType 0 (time data)
ydata_type SHORT16 or LONG32
scanData 1
Thetimedatashouldalwaysbethefirstresultinatimecapturefile. Toconvertthedatafromitsinteger
form to volts, you need to determine the channel header that belongs to the data and get the scaling factor
from the channel header.
The time capture data is stored with multiple rows of data, one row for each channel of captured data. For
a given row, the desired SDF_VECTOR_HDR number is (first_VECTOR_recordNum + row). After
locating the SDF_VECTOR_HDR for this row, find the channel number from the_CHANNEL_record[0].
After locating the SDF_CHANNEL_HDR, you can scale the time capture data to volts by using the scale
values in the SDF_CHANNEL_HDR. For each time capture value in the data result (defined as
time_data[i]):
time_volts[i] = channelOffset +(channelScale
 time_data[i])
To determine the total number of time capture points, you need to know now many scans are in the file.
The number of usable scans can be determined from the last_scan_index field in the
SDF_SCAN_STRUCT. The number of usable points per scan can be determined from the
last_valid_index in the SDF_DATA_HDR. The total number of time capture data points is:
time_capture_points = (last_valid_index+1)
 (last_scan_index+1)
Overload Data
Overload data is identified in a time capture file with the following SDF_DATA_HDR attributes:
dataType 46 (overload data)
ydata_type SHORT16
num_of_points 1
scanData 1
This data result identifies whether an overload occurred in each scan of a time capture. There is one of
these results for each channel of a time capture.
Standard Data Format (SDF)
B-36