For the 701280 Frequency Input Module with a 4th order IIR 6Hz lowpass filter, a 60Hz sine wave (FM modulated with a square wave) was measured with deviations of ± 3Hz. Please download and view the attached image for a screenshot of multiple measurements.
The top waveform is the output of the 701280 module driven with a 60Hz unit step deviated at ± 3Hz. The 701280 module is measuring in Frequency mode.
The middle waveform is the top waveform after an IIR 6Hz LP filter has been applied.