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Chapter 2 Function Reference — CTR_Period
NI-DAQ FRM for PC Compatibles 2-98
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National Instruments Corporation
CTR_Period
Format
status = CTR_Period (deviceNumber, ctr, timebase)
Purpose
Configures the specified counter for period or pulse-width measurement.
Parameters
Input
Parameter Discussion
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 selects 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.
8: SOURCE3 used as timebase if 1 ≤ ctr ≤ 5 or SOURCE 8 used as timebase
if 6 ≤ ctr ≤ 10.
9: SOURCE4 used as timebase if 1 ≤ ctr ≤ 5 or SOURCE 9 used as timebase
if 6 ≤ ctr ≤ 10.
Name Type Description
deviceNumber i16 assigned by configuration utility
ctr i16 counter number
timebase i16 timebase value