Why does my code report an extra NI DAQ channel and reduce my sampling rate when I try to start my NI DAQ session?

I am using a NI 9211 thermocouple DAQ module with the MATLAB Data Acquisition Toolbox to acquire temperature data. The module has a max of 4 channels with an aggregate sampling rate of 12Hz (12Hz/channel at one channel, 6Hz/channel for 2 channels, etc.).

I am running into an issue with being unable to acquire data at the max sampling rate due to MATLAB detecting an extra channel to the ones I initialize. For example, I initialize 2 channels, set sampling rate at 6 Hz (12Hz aggregate), and try and start my data acquisiiton session when I get the following error. This happens at the 4 channel max as well (MATLAB reports 5 channels with a max sampling rate of 2.4Hz/channel).

>> dataLoggingScript

Warning: The Rate property was reduced to 12 due to changes in the session configuration.

Warning: The Rate property was reduced to 6 due to changes in the session configuration.

Error using dataLoggingScript (line 50)

NI Error -200081:

Sample rate exceeds the maximum sample rate for the number of channels specified.

Reduce the sample rate or the number of channels. Increasing the convert rate or reducing the sample delay might also alleviate

the problem, if you set either of them.

Number of Channels: 3

Sample Rate: 6.0

Maximum Sample Rate: 4.0

Task Name: _unnamedTask<21>

Status Code: -200081

>> session

session =

Data acquisition session using National Instruments hardware:

Will run continuously at 6 scans/second until stopped.

Number of channels: 2

index Type Device Channel MeasurementType Range Name

----- ---- ------ ------- --------------- --------------------- ----

1 ai Dev1 ai0 Thermocouple -200 to +1250 Celsius

2 ai Dev1 ai1 Thermocouple -200 to +1250 Celsius

Has anybody had similar issues?