National Instruments Welding System 321645c-01 Manual De Usuario

Chapter 2

Function Reference — DAQ_Monitor

©

 National Instruments Corporation

2-127

NI-DAQ FRM for PC Compatibles

in 

Lab_ISCAN_Start

. If you are using an AMUX-64T, channel can be equal to any one of 

the AMUX-64T channels.

Range:

–1 for data from all channels being sampled.
n where n is one of the channels being sampled.

sequential is a flag that enables or disables the return of consecutive or oldest blocks of data 
from the acquisition buffer. A call to 

DAQ_Monitor

 with the value of sequential equal to one 

returns a block of data that begins where the last sequential call to 

DAQ_Monitor

 left off. A 

call to 

DAQ_Monitor

 with sequential equal to zero returns the most recent block of data 

available.

0:

Most recent data.

1:

Consecutive data.

numPts is the number of data points you want to retrieve from the buffer being used by the 
acquisition operation. If the channel parameter is equal to –1, numPts must be an integer 
multiple of the number of channels contained in the scan sequence. If you are using one or 
more AMUX-64T boards, remember that the actual number of channels scanned is equal to 
the value of the numChans parameter you selected in 

SCAN_Setup

, multiplied by the 

number of AMUX-64T boards, multiplied by 4.

Range:

(if channel equals –1) 1 to the value of count in the 

DAQ_Start

, 

SCAN_Start

, 

or 

Lab_ISCAN_Start

 call.

(if channel is not equal to 1) 1 to the number of points per channel that the 
acquisition buffer can hold.

monitorBuffer is the destination buffer for the data. It is an integer array. monitorBuffer 
must be at least big enough to hold numPts worth of data. Upon the return of 

DAQ_Monitor

, 

monitorBuffer contains a snapshot of a portion of the acquisition buffer.

newestPtIndex is the offset into the acquisition buffer of the newest point returned by 

DAQ_Monitor

. When the value of the sequential flag is 0, newestPtIndex is useful in 

determining whether you are seeing the same data over and over again. If 

DAQ_buffer

 

is the name of the buffer selected in the 

DAQ_Start

 call, for example, 

monitorBuffer[numPts – 1] = 

DAQ_buffer

[newestPtIndex], if 

DAQ_buffer

 is 

zero based.

daqStopped returns an indication of whether the data acquisition has completed.

0:

The DAQ operation is not yet complete.

1:

The DAQ operation has completed (or halted due to an error).