User manual

Chapter 3 Software Overview
© National Instruments Corporation 3-81 NI-DAQ User Manual for PC Compatibles
Figure 3-27.
Counter Timing and Output Types
Figure 3-27 represents a counter generating a delayed pulse (see
CTR_Pulse
in the function reference) and demonstrates the four forms
the output pulse can take given the four different types of output signals
supported. The TC toggled positive logic output looks like what is expected
when generating a pulse. For most of the Counter/Timer functions,
TC toggled output is the preferred output configuration; however, the
other signal types are also available. The starting signal, shown in
Figure 3-27, represents either a software starting of the counter, for the
no-gating case, or some sort of signal at the GATE input. The signal is
either a rising edge gate or a high-level gate. If the signal is a low-level
or falling edge gate, the starting signal simply appears inverted. In
Figure 3-27, the counter is configured to count the signal output changes
state with respect to the rising edge of the timebase.
Programmable Frequency Output Operation
The PC-TIO-10 provides two 4-bit programmable frequency output
signals. The signals are divided-down versions of the selected timebase.
Any of five internal timebases, counter SOURCE inputs, and
counter GATE inputs can be selected as the FOUT source. See the
CTR_FOUT_Config
function description in the NI-DAQ Function
Reference Online Help file for FOUT use and timing information.
0 < sync period < 1
1
Timebase
Starting
Signal
TC Toggle
Output
TC Pulse
Output
units = timebase period
Positive
Negative
Positive
Negative
1 1