National Instruments 321645c-01 Welding System User Manual


 
Chapter 2 Function Reference GPCTR_Set_Application
NI-DAQ FRM for PC Compatibles 2-228
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National Instruments Corporation
For example, assume that you want to generate a pulse 200 ns long after 150 ns of delay.
You need to set
ND_COUNT_1 to 150 ns/50 ns = 3 and ND_COUNT_2 to 200 ns/50 ns = 4.
Figure 2-19 shows the scenario of a counter used for
ND_SINGLE_PULSE_GNR after the
following programming sequence:
GPCTR_Control(deviceNumber, gpctrNum, ND_RESET)
GPCTR_Set_Application(deviceNumber, gpctrNum, ND_SINGLE_PULSE_GNR)
GPCTR_Change_Parameter(deviceNumber, gpctrNum, ND_COUNT_1, 3)
GPCTR_Change_Parameter(deviceNumber, gpctrNum, ND_COUNT_2, 4)
Select_Signal(deviceNumber, gpctrNumOut, gpctrNumOut,ND_LOW_TO_HIGH)
GPCTR_Control(deviceNumber, gpctrNum, ND_PROGRAM)
In Figure 2-19, the following behavior is present:
Source is the signal present at the counter source input.
Output is the signal present at the counter output.
Armed is the value you would read from the counter if you called the
GPCTR_Watch
function with entityID =
ND_ARMED. The different values illustrate behavior at different
times.
Figure 2-19.
Single Pulse Generation
Use the GPCTR_Watch function with entityID = ND_ARMED to monitor the progress of the
pulse generation process. The generation completes when entityValue becomes
ND_NO.
Typically, you find modifying of the following parameters through the
GPCTR_Change_Parameter function useful when the counter application is
ND_SINGLE_PERIOD_MSR. You can change the following:
ND_COUNT_1 and ND_COUNT_2 to any value between 2 and 2
24
– 1 for E Series and 445X
devices, and to any value between 2
32
– 1 for 6602 and 455X devices. The defaults are
given for illustrative purposes only.
ND_SOURCE to ND_INTERNAL_100_KHZ. With this timebase, you can generate pulses
with a delay and length between 20 µs and 160 s for E Series and 445X devices and
Source
Armed
No
Output
No
Count_1 = 3
Count_2 = 4
Yes