ADS7952-Q1: The sampling accuracy

Hi,

Please help me with the following questions about the sampling of ADS7952.
The current project is 800V high-pressure acquisition, and ADS7952-Q1 adopts manual mode for channel selection.
1. When the sampling channel 0 is not applied with voltage, the upper computer can read the multiple voltage of 0.45v. When running out and applying voltage, the collected voltage value is added with this initial read voltage value;
2. When each line is collected separately, the collected voltage is smaller than the theoretical voltage value, which is a multiple of 0.45v;
3. Manual mode will have an impact on the sampling of adjacent channels. When two channels are connected at the same time, the voltage of the lower one will be larger than that of the upper one.
4. The higher the voltage, the larger the voltage error collected by channel 1 will be

data:

We are using 2*REF now. When channel 0 is not connected to 63.2v, the upper computer reads 0.25432v voltage or twice or three times of runout. After connecting 63.2v, the voltage is about 63V.
When the single channel 1 connects to 63.2v, the voltage around 61V can be picked up.
When the single channel 2 is connected to 63.2v, the voltage around 61V can be picked up.
The rear channel connected separately is similar;
Channel 0 and channel 1 are connected to 63.2v at the same time. Channel 0 can pick up the voltage of about 63V, while channel 1 can pick up the voltage of 62.5671v.
Channel 1 and channel 2 are connected with 63.2v voltage at the same time. Channel 1 can pick up about 61V voltage, and channel 2 can pick up 62.5671v voltage. Adjacent channels will have an impact.
When channels 0, 1 and 2 are fully connected to 63.2v, if channel 0 is about 63V, 62.5671v can be obtained in channels 1 and 2.
The error sizes between channels are all multiples of 0.25432v.

Thanks!