VTI Instruments EX1000A, Руководство пользователя

Страница: 206 / 320

VTI Instruments Corp.
206 EX10xxA/RX1032/EX1044 Function Calls
vtex10xxA_read_fifo
F
UNCTION
P
ROTOTYPE
ViStatus vtex10xxA_read_fifo(ViSession vi , ViInt32 maxscans , ViReal64 ts_secs[] , ViReal64 ts_fsecs[] , ViPInt32
numscans , ViInt32 maxdata , ViReal64 data[] , ViPInt32 numdata , ViInt32 to_secs );
F
UNCTION
P
ARAMETERS
vi = contains a session handle to the instrument. This handle is obtained by the function and remains valid until the
session is closed.
maxscans = the maximum number of scans to return. Valid return values: 1 through (2
31
-1).
ts_secs[] = a return array of scan start times, specified in seconds since the epoch (Jan. 1, 1970).
ts_fsecs[] = a return array of scan start times, specified in seconds since the last full second represented in ts_secs[] .
numscans = an integer output value indicating the actual number of scans retrieved. Valid
maxdata = the maximum length of the return data array. Valid return values: 1 through (2
31
-1).
data[] = a return array of sample data.
numdata = an integer output value indicating the actual number of samples retrieved. Valid return values: 1 through
(2
31
-1).
to_secs = the timeout period (in seconds), indicating how long to poll the EX10xxA for data. Valid return values:
0 through (2
31
-1), where 0 represents an infinite timeout period.
D
ATA
I
TEM
R
ESET
V
ALUE
Not applicable to this function.
D
ESCRIPTION
This function retrieves acquisition data. Data returned by this function includes input channel measurement data and
the start time of each scan.
NOTE In order to provide the maximum reading buffer capacity for future acquisitions, data is deleted from
the FIFO memory upon retrieval.
E
XAMPLE
ViInt32 channels[5] = {0, 1, 2, 3, 4};
ViReal64 ts_secs[20], ts_fsecs[20], data[100];
ViInt32
num_scans, num_data;
vtex10xxA_set_scanlist(vi, channels, 5);
vtex10xxA_set_trig_source_timer(vi, 0.01);
vtex10xxA_set_trigger_count(vi, 20);
vtex10xxA_init_imm(vi);
vtex10xxA_read_fifo(vi, 20, ts_secs, ts_fsecs, &num_scans, 100, data, &num_data, 3);