Signal Ghosting using NI USB-6001 with Simulink

We have been working with the USB-6001 in our experiment, and any time more than 1 channel is being used (i.e. AI0 and AI1) the signals seem to be crossing between the two channels. Shown below is the scope result of a sine wave supplied to channel 0. Channel 0 is yellow and channel 1 is blue. The blue signal is channel 1, which is not connected to any signal. The result, however, shows channel 1 closely following channel 0.

An image of the Simulink code used to process this signal is shown below.

Can anyone help me troubleshoot this as to why this ghosting is happening. We also tried using DAQ with LabVIEW which worked just fine without any ghosting but couldn't understand this issue on matlab We are using R2017a ver.

Thank You

[Walter Roberson]

Is channel 1 tied to ground?

[Ankit Gupta]

Yes, it is and it still shows the same ghosting.

Answer 1

[Andrei]

For an explanation on why you observe ghosting when acquiring from a multiplexed DAQ device such as NI USB 6001 with no signal connected to channel AI1 see http://digital.ni.com/public.nsf/allkb/73CB0FB296814E2286256FFD00028DDF?OpenDocument

If you connect signals to both AI0 and to AI1 and still observe ghosting, make sure that TerminalConfig (Differential/SingleEnded) specified in the Analog Input block channel parameters is as intended and that the external wiring is correct for the specified TerminalConfig (refer to DAQ device data sheet pinout diagram).

[Ankit Gupta]

We still sees ghosting , both channels are connected and selected differential. both channels follows the high voltage signal. we also tried daq devices and it happens in other daq devices too( same model)