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AD 7193, Noise Count Histogram

Hello community,

Why am i not getting anywhere close the Noise Distribution Histogramm shown on Page 15, Figure 10.
(LT 3042 Reference, Shorted Ain1& Ain2, PMOD Ad5)

my Setup:

i am using the AD7193 (placed on the PMOD AD5) board to measure a load cell.
The Load cell has maximum capacity of approx 100g and has a rating of approx 0.7mv/V.
An LT 3042 chip supplies the excitation voltage (and is wired to the Refin2+/- to provide an external reference) at 3.3 volts which result in a ratiometric measurement.
So far the setup works and has a noise of ~ +/-0.003 gramms (by averaging 1023 measurements, fully differential, which gives me an output data rate on my arduino nano of approx 1 Hz).

If i short Ain1&Ain2 with a jumper (and stop averaging) my noise is way higher than what is shown on Page 15, Figure 10 and on page 17 Figure 19.
If i understand the histogram on page 15 correctly the output rate of 2400 hz means that there is no prior averaging?
What could possible be the reason for such high noise? Since the PCB Layout is done by Digilent, i dont think that the Layout is the reason (in case of shorted out pins).

PS: I am a mechanical engineer who tries to understand the electronic world.

Thanks for your help.