National Instruments 321645c-01 用户手册

Chapter 2

Function Reference — CTR_Square

NI-DAQ FRM for PC Compatibles

2-110

©

 National Instruments Corporation

Causes the specified counter to generate a continuous square wave output of specified duty 
cycle and frequency.

ctr is the counter number.

Range:

1, 2, or 5 for an MIO device except the E Series devices.
1 through 10 for a PC-TIO-10.

timebase is the timebase, or resolution, to be used by the counter. timebase has the following 
possible values:

–1:

Internal 5 MHz clock used as timebase (200 ns resolution) (AT-MIO-16F-5, 
AT-MIO-64F-5, AT-MIO-16X, and PC-TIO-10 only).

0:

TC signal of ctr–1 used as timebase.

1:

Internal 1 MHz clock used as timebase (1 µs resolution).

2:

Internal 100 kHz clock used as timebase (10 µs resolution).

3:

Internal 10 kHz clock used as timebase (100 µs resolution).

4:

Internal 1 kHz clock used as timebase (1 ms resolution).

5:

Internal 100 Hz clock used as timebase (10 ms resolution).

6:

SOURCE1 used as timebase if 1 

≤

 ctr 

≤

 5 or SOURCE 6 used as timebase 

if 6

≤

ctr 

≤

 10.

7:

SOURCE2 used as timebase if 1 

≤

 ctr 

≤

 5 or SOURCE 7 used as timebase 

if 6

≤

ctr 

≤

 10.

i16

assigned by configuration utility

i16

counter number

i16

timebase value

u16

period of the square wave

u16

period of the square wave