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Chapter 2 Function Reference — GPCTR_Change_Parameter
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National Instruments Corporation 2-205 NI-DAQ FRM for PC Compatibles
paramID = ND_SECOND_GATE (6602 and 455X devices only)
This signal controls the operation of the general-purpose counter in some applications.
Corresponding legal values for paramValue are shown below:
•
ND_PFI_37, ND_PFI_33, ND_PFI_29, ND_PFI_25, ND_PFI_21, ND_PFI_17,
ND_PFI_13, ND_PFI_9
• ND_RTSI_0
through ND_RTSI_6—the seven RTSI lines.
•
ND_OTHER_GPCTR_OUTPUT
(See Table 2-22 for definition of the other counter).
Note
ND_PFI_37
and
ND_PFI_33
are
not available on 455X devices.
The default values of paramValue for paramID =
ND_SECOND_GATE
a
re shown in
Table 2-26.
paramID =
ND_SECOND_GATE_POLARITY
(6602 and 455X devices only)
This gate signal controls the operation of the general-purpose counters in the start-stop
applications. In those applications you can use polarity of the second gate signals to modify
behavior of a counter. Corresponding legal values for paramValue are shown below:
• ND_POSITIVE
• ND_NEGATIVE
The meaning of the two
ND_SECOND_GATE_POLARITY
selections is described in the
GPCTR_Set_Application
f
unction.
paramID =
ND_INITIAL_COUNT
The general-purpose counter starts counting from this number when the counter is configured
for one of the simple event counting and time measurement applications. Corresponding legal
values for paramValue are shown in Table 2-27.
Table 2-26.
Default Second Gate Selection
gpctrNum 6602 Devices 455X Devices
ND_COUNTER_0 ND_PFI_37 ND_PFI_29
ND_COUNTER_1 ND_PFI_33 ND_PFI_25
ND_COUNTER_2 ND_PFI_29
N/A
ND_COUNTER_3 ND_PFI_25
N/A
ND_COUNTER_4 ND_PFI_21
N/A
ND_COUNTER_5 ND_PFI_17
N/A
ND_COUNTER_6 ND_PFI_13
N/A
ND_COUNTER_7 ND_PFI_9
N/A