National Instruments Welding System 321645c-01 Manual De Usuario

Chapter 2

Function Reference — GPCTR_Set_Application

NI-DAQ FRM for PC Compatibles

2-230

National Instruments Corporation

In Figure 2-20, the following behavior is present:

•

Gate is the signal present at the counter gate input.

•

Source is the signal present at the counter source input.

•

Output is the signal present at the counter output.

•

Armed is the value you would read from the counter if you called the

GPCTR_Watch

function with entityID =

ND_ARMED

. The different values illustrate behavior at different

times.

Figure 2-20. Single Triggered Pulse Generation

Use the

GPCTR_Watch

function with entityID =

ND_ARMED

to monitor the progress of the

pulse generation process. The generation completes when entityValue becomes

ND_NO

Typically, you will find modification of the following parameters through the

GPCTR_Change_Parameter

function useful when the counter application is

ND_SINGLE_TRIG_PULSE_GNR

. You can change the following:

•

ND_COUNT_1

and

ND_COUNT_2

to any value between 2 and 2

– 1. The defaults are

given for illustrative purposes only.

•

ND_SOURCE

ND_INTERNAL_100_KHZ

. With this timebase, you can generate pulses

with a delay and length between 20 µs and 160 s. The timing resolution will be lower than
if you are using

ND_INTERNAL_20_MHZ

timebase.

•

ND_GATE

to any legal value listed in the

GPCTR_Change_Parameter

function

description.

•

ND_GATE_POLARITY

ND_NEGATIVE

. A high-to-low transition of the gate signal

initiates the pulse generation timing.

You can use the

GPCTR_Change_Parameter

function after calling

GPCTR_Set_Application

and before calling

GPCTR_Control

with

action =

ND_PROGRAM

ND_PREPARE

Source

Armed

Output

Count_1 = 3

Count_2 = 4

Yes

Gate