NIDMM_ATTR_POWERLINE_FREQ

Specific Attribute

Data type	Access	Coercion	High-Level Function
ViReal64	R/W	None	niDMM_ConfigurePowerlineFrequency

Description

Specifies the powerline frequency. The NI 4050 and NI 4060 use this value to select an aperture time to reject powerline noise by selecting the appropriate internal sample clock and filter. The NI 4065 and NI 4070/4071/4072 use this value to select a timebase for setting the NIDMM_ATTR_APERTURE_TIME attribute in powerline cycles (PLCs).

After configuring powerline frequency, set the NIDMM_ATTR_APERTURE_TIME_UNITS attribute to PLCs.  When setting the NIDMM_ATTR_APERTURE_TIME attribute, select the number of PLCs for the powerline frequency. For example, if powerline frequency = 50 Hz (or 20ms) and aperture time in PLCs = 5, then aperture time in Seconds = 20ms * 5 PLCs = 100 ms. Similarly, if powerline frequency = 60 Hz (or 16.667 ms) and aperture time in PLCs = 6, then aperture time in Seconds = 16.667 ms * 6 PLCs = 100 ms.

Defined Values

NIDMM_VAL_50_HERTZ	50 Hz
NIDMM_VAL_60_HERTZ	60 Hz

Note  For 400 Hz powerline frequency, use the 50 Hz setting.