Changing from high-resolution mode to high-speed mode (NI-9216 and others)

[alecote]

Hello!
You may be reading this because you have an acquisition module that has more than one conversion time modes, and you wonder how to change from the default. It was the case with my NI-9216 RTD modules having high resolution (200ms) and high speed (2.5ms) modes. It took me some time reading the nidaqmx-python doc and the NI DAQmx doc to figure it out, so I thought I would share an example here to help others.

If there is a cleaner way to do this, please let me know!

Note that the code below is specific to an RTD module. The important details are nidaqmx.constants.ADCTimingMode and ai_adc_timing_mode.

import nidaqmx
from nidaqmx.constants import (
    AcquisitionType,
    READ_ALL_AVAILABLE,
    ADCTimingMode,
    ResistanceConfiguration,
    RTDType,
    ExcitationSource
)

with nidaqmx.Task() as task:
    my_rtd_channel = task.ai_channels.add_ai_rtd_chan("Dev1/ai0",
                        rtd_type=RTDType.PT_3851,
                        resistance_config=ResistanceConfiguration.FOUR_WIRE,
                        current_excit_source=ExcitationSource.INTERNAL,
                        current_excit_val=0.001,
                        r_0=100,
                        min_val=-60,
                        max_val=150,
                        ) 

    task.timing.cfg_samp_clk_timing(1000.0, sample_mode=AcquisitionType.FINITE, samps_per_chan=50)
    
    ### THIS LINE HERE ###
    my_rtd_channel.ai_adc_timing_mode = ADCTimingMode.HIGH_SPEED

    data = task.read(READ_ALL_AVAILABLE)

[bkeryan]

Some other ways to do it:

# Set the property for all channels in the task.
task.ai_channels.all.ai_adc_timing_mode = ADCTimingMode.HIGH_SPEED

# Set the property for specific channels by name. 
task.ai_channels["Dev1/ai0:3"].ai_adc_timing_mode = ADCTimingMode.HIGH_SPEED

# Set the property for a specific channel or range of channels by index.
task.ai_channels[0].ai_adc_timing_mode = ADCTimingMode.HIGH_SPEED
task.ai_channels[0:4].ai_adc_timing_mode = ADCTimingMode.HIGH_SPEED