SCXI 1125 filtering problem

[aspired]

I am using a SXCI 1125 with Terminal Block SCXI 1305.
The 1125 is jumperless. So to set the gain and filter, i changeed it in MAX for each channel. I have set the filter to 10Khz. However when I use a function generator to input a sine wave, the amplitude of the signal begins to drop off around 4hz.
I have verified using a scope and a multimeter that the signal from the CRO is around 0.6Vrms for all frequencies in the range of 1 - 1Khz.
I am sampling at around 2Khz. Why it is creating a low pass filter of 4 hz by itself. I have double checked the configuration several times.
I have an 1121 and it is reading in the voltages fine.

[Matthew C]

Hello aspired,

The SCXI-1305 has channel configurable AC/DC coupling and signal referencing. It is possible that the 1305 is not configured correctly for use with the 1125. Make sure the floating and ground-referenced signal configuration switches are set to Ground (G). Also, you may want to enable DC coupling by flipping AC/DC coupling configuration switches to DC. This will disengage the single-pole high pass filters within the 1305 that may be interfering with your signal.

I hope this helps!

Matthew C
Applications Engineer
National Instruments