National Instruments Welding System 321645c-01 Manual De Usuario

Chapter 2

Function Reference — Configure_HW_Analog_Trigger

NI-DAQ FRM for PC Compatibles

2-86

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 National Instruments Corporation

•

ND_HIGH_HYSTERESIS

—The trigger is generated when the signal value is greater than 

the highValue, with hysteresis specified by lowValue.

Figure 2-7.  ND_HIGH_HYSTERESIS

•

ND_LOW_HYSTERESIS

—The trigger is generated when the signal value is less than the 

lowValue, with hysteresis specified by highValue.

Figure 2-8.  ND_LOW_HYSTERESIS

Use the trigSource parameter to specify the source of the trigger you want to use. For E Series 
devices, the legal values are 

ND_PFI_0

 and 

ND_THE_AI_CHANNEL

.

Set trigSource to 

ND_PFI_0

 if you want the trigger to come from the PFI0/TRIG1 pin. You 

need to connect the analog signal you want to use for triggering to the PFI0/TRIG1 pin. To 
generate triggers based on an analog signal that takes a wide range of values between –10 V 
and +10 V, you should use this setting. 

You should select 

ND_THE_AI_CHANNEL

 for trigSource only to generate triggers based on a 

low-range analog signal, if you are concerned about signal quality and are using a shielded 
cable, or if you want the trigger to be based on an analog input channel in the differential 
mode. Using this selection is non-trivial.

Trigger

Trigger