User manual

Chapter 3 Software Overview
NI-DAQ User Manual for PC Compatibles 3-78 ni.com
CTR_State
Returns the OUT logic level of the
specified counter.
CTR_Stop
Suspends operation of the specified
counter so that NI-DAQ can restart the
counter operation.
Counter/Timer Operation for the CTR Functions
Figure 3-26 shows the 16-bit counters available on the PC-TIO-10.
Figure 3-26. Counter Block Diagram
Each counter has a SOURCE input, a GATE input, and an output
labeled OUT.
The counters can use several timebases for counting operations. A counter
can use the signal supplied at any of the Am9513 five SOURCE or GATE
inputs for counting operations. The Am9513 also makes available five
internal timebases that any counter can use:
• 1MHzclock(1µsresolution)
• 100 kHz clock (10 µs resolution)
• 10 kHz clock (100 µs resolution)
• 1 kHz clock (1 ms resolution)
• 100 Hz clock (10 ms resolution)
Note
A 5 MHz internal timebase (200 ns resolution) is also available on SOURCE 5 for
counters 1 to 5, and SOURCE 10 for counters 6 to 10 on the PC-TIO-10.
You can also program the counter to use the output of the next lower
order counter as a signal source. This arrangement is useful for counter
concatenation. For example, you can program counter 2 to count the output
of counter 1, thus creating a 32-bit counter.
GATE
SOURCE
Counter OUT