Hi,
I am in the process of upgrading a vb6 application from Traditional NI-DAQ to DAQmx. I am transitioning functionality from the legacy function scan_op to the DAQmx function DAQmxReadAnalogF64. I have found a troublesome behavior that I can't seem to find documented in the help. When I add AI channels via a range (see ex 1), as in the example code that came along with the DAQmx installation, the function behaves correctly. However, when I try to add channels individually (see ex 2) or in a list (see ex 3), I get an error that says that there is not enough room in the buffer to store the data. This leads me to believe two things: 1) This function requires contiguous channels and 2) This function requires the channels to be added as a range. If this is the case, this function will not satisfy the requirements for this project. It is essential that I am able to add channels that are not contiguous. My questions now are: Are my conclusions about this function correct? If so, what other function(s) would satisfy my requirements? Thank you for any help.
Ex 1 - works
DAQmxCreateAIVoltageChan(taskHandle, "Dev1/ai0:2", "", DAQmx_Val_Cfg_Default, -10, 10, DAQmx_Val_VoltageUnits1_Volts, "")
Ex 2 - doesn't work
DAQmxCreateAIVoltageChan(taskHandle, "Dev1/ai0", "", DAQmx_Val_Cfg_Default, -10, 10, DAQmx_Val_VoltageUnits1_Volts, "")
DAQmxCreateAIVoltageChan(taskHandle, "Dev1/ai1", "", DAQmx_Val_Cfg_Default, -10, 10, DAQmx_Val_VoltageUnits1_Volts, "")
DAQmxCreateAIVoltageChan(taskHandle, "Dev1/ai2", "", DAQmx_Val_Cfg_Default, -10, 10, DAQmx_Val_VoltageUnits1_Volts, "")
Ex 3 - doesn't work
DAQmxCreateAIVoltageChan(taskHandle, "Dev1/ai0,Dev1/ai1,Dev1ai2", "", DAQmx_Val_Cfg_Default, -10, 10, DAQmx_Val_VoltageUnits1_Volts, "")
Error message received
Error #-200229 : Buffer is too small to fit read data.
