Issues sampling Analog values from Analog Adapter

Hi all,
i am having issues getting stable readings from my analog adapter. It is connected tot 2 pressure sensors that are giving values between 0-10V. I have set the adapter up so that it has all 4 inputs set for 0-10V, and have a python script reading the values manually. I have checked the inputs using a digital multimeter and it is giving me reasonably stable and consistent results, but when I run the script, the vaules vary wildly, and I am not sure why, hence, nor how to fix it. Any troubleshooting tips would be welcome.

To show you what I mean about the fluctuating outputs, here is a sample of what I get, even though it should be the same every time I sample.

Cheers,

Tom.

#> python analog_read.py

Sump value is 2.96710210611
and tank value is 2.82676619568

#> python analog_read.py

Sump value is 1.59381498267
and tank value is 4.62106105039

#> python analog_read.py

Sump value is 0.35083977606
and tank value is 5.04206878166

#> python analog_read.py

Sump value is 2.60623833644
and tank value is 2.04489469475

#> python analog_read.py

Sump value is 1.64393495068
and tank value is 4.94182884564

#> python analog_read.py

Sump value is 1.39333511064
and tank value is 3.60863769661

#> python analog_read.py

Sump value is 0.641535590509
and tank value is 4.99194881365

Oh, I forogt to mention too, that I am connected to a 6V DC mains power supply powering both the adapter and the sensor, and the adapter is NOT set to sleep. It is always on, so it should not be any settling time issues.

Cheers,

Tom