If you are using our python libraries then you can set the conversion mode to continuous with the set_conversion_mode(1) function.
bus = i2c_helper.get_smbus()
adc = ADCPi(bus, 0x68, 0x69, 12)
For our C library you set the 5th parameter in the read_voltage() function to 1.
read_voltage(0x68,1, 12, 1, 1));
You will also need to set the sample bit rate to be 12 bit for it to read at 200Hz.
In python on a Raspberry Pi 3 you should be able to get around 250 samples per second when reading from a single channel in 12 bit mode. Reading from two channels on the same ADC chip, for example channels 1 and 3 will reduce the sample rate to around 170sps as it takes a short amount of time to change channel.