I fixed this problem by restarting k1visbs.

At the beginnig, CFC in STATEWORD was turnd yellow,

DC status becomes "0x2000",

and the message "Modified File Detected" was displayed on DAQ LOAD(see attachement 1).

This means the real-time model is not rebooted after someone executed "make install-k1xxx".

So installed channel list is conflict with one used by a running model.

The spectra of *_IN1 and *_IN1_DAQ looks like same behavior (see attachement 2).

The harmonics of 16Hz also disppears.

Please check whether the problem is resolved.