how to acquire data from NI 9205

Here is the data acquisition information.

ni: National Instruments NI 9205NI 9205 (DSUB) (Device ID: 'cDAQ9191-1C434351Mod1')

Analog input subsystem supports:

4 ranges supported

Rates from 0.1 to 250000.0 scans/sec

32 channels ('ai0' - 'ai31')

'Voltage' measurement type

This module is in slot 1 of the 'cDAQ-9191' chassis with the name 'cDAQ9191-1C434351'.

I want to collect data from NI 9205 for 20 seconds in two channles, and sample rate is 8000.

In labview, I can easliy collect the data. But in maltab, I tried many time, still does not work.

Below show my code, after add channels, I do not know what to do next. Is any one know what is the command to acquire the data and what is the command to set the sample rate? Thanks a lot.

s = daq.createSession('ni');

s.addAnalogInputChannel('cDAQ9191-1C434351Mod1', 'ai0', 'Voltage');

s.addAnalogInputChannel('cDAQ9191-1C434351Mod1', 'ai1', 'Voltage');