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Chapter 10 Easy I/O for DAQ Library
© National Instruments Corporation 10-31 LabWindows/CVI Standard Libraries
Parameters
Input
device
short
integer
Assigned by configuration utility.
counter
string The counter to be used for the counting
operation.
counterSize
unsigned
short
integer
Determines the size of the counter used to
perform the operation: ONE_COUNTER or
TWO_COUNTERS.
gateWidthSampleTimeinSec
double The desired length of the pulse used to gate
the signal. The lower the signal frequency,
the longer the Gate Width must be.
maxDelayBeforeGateSec
double The maximum expected delay between the
time the function is called and the start of
the gating pulse. If the gate signal does not
start in this time, a timeout occurs.
counterMinus1GateMode
unsigned
short
integer
The gate mode for counter-1.
Output
actualGateWidthSec
double The length in seconds of the gating pulse
that is used.
overflow
short
integer
1 = counter rolled past terminal count; 0 =
counter did not roll past terminal count. If
overflow is 1, the value of frequency is
inaccurate.
valid
short
integer
Set to 1 if the measurement completes
without a counter overflow. A timeout and
a valid measurement may occur at the same
time. A timeout does not produce an error.
timeout
short
integer
Set to 1 if the time limit expires during the
function call. A timeout and a valid
measurement may occur at the same time.
A timeout does not produce an error.
frequency
double The frequency of the signal. It is computed
as the (number of rising edges) /
(actualGateWidthSec).