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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

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).

ND_PFI_37

ND_PFI_33 

The default values of paramValue for paramID =

 

ND_SECOND_GATE

 a

re shown in 

Table 2-26.

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.

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

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