National Instruments Welding System 321645c-01 Manual De Usuario

Chapter 2

Function Reference — WFM_Op

NI-DAQ FRM for PC Compatibles

2-436

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 National Instruments Corporation

If you have changed the analog output configuration from the defaults by changing the 
jumpers on the device, you must call 

AO_Configure

 to set the software copies of the settings 

prior to calling 

WFM_Op

.

NI-DAQ ignores the group settings made by calling 

WFM_Group_Setup

 when you call 

WFM_Op

 and the settings are not changed after NI-DAQ executes you execute 

WFM_Op

.

SCAN_Start

For the AT-MIO-16F-5, AT-MIO-64F-5, and AT-MIO-16X, you can use counter 1, 2, and 5, 
as well as a dedicated external update signal, to generate either interrupt or DMA requests. 
If you use counter 1 or 2, a RTSI line must also be available. NI-DAQ uses the first available 
counter among counters 5, 2, and 1, in that order.

For Lab and 1200 Series analog output devices, if the rate is smaller than 15.26 and counter 
B0 is busy in a data acquisition or counting operation, waveform generation cannot proceed.

On Am9513-based MIO devices, to externally trigger a waveform generation operation, you 
can do so by first changing the gating mode of the counter NI-DAQ will use. 

WFM_OP

 will use either the default gating mode (none) or the gating mode you specify through 

the 

CTR_Config

 function. You will need to connect your trigger signal to the gate pin on the 

I/O connector. Refer to the 

CTR_Config

 function description for details.

On E Series devices, you can externally trigger a waveform generation operation in a variety 
of ways. Refer to the 

Select_Signal

 function for more details.

The DSA devices use 32-bit data buffers. If you are using C or Delphi, you will need to 
typecast your i32 array to i16 when you call 

WFM_Op

. If you are using Visual Basic, you 

should use the 

nidaqr32.bas 

file (instead of 

nidaq32.bas

) to relax type checking on 

buffer. The DSA devices use the upper 18 bits of each buffer element. The lower 14 bits are 
ignored and you should set them to zero. You can move each data point into the upper 18 bits 
with a left shift operation by multiplying it by 16,384.