lvdaq

[KirkSmith]

Labview 6.1,Windows 2000

I am analyzing an application that measures the period of a rotating shaft. This application is designed to determine how long it takes the shaft to stop rotating. The hardware involved, is the 6023E Multi-I/O card. The application makes repeated calls to Lvdaq.dll. The function call of interest is “Counter_Read_BufferInterface”. Of particular interest in this function call is the returned value of “acquisition state”. The possible return values are:       

                                    0: Running

                                    1: Finished with backlog

                                    2: Finished without backlog

                                    3: Paused

                                    4: No acquisition

My question is; How is the acquisition state determined? What measure being made by this function call causes the acquisition state to change from ‘Running” to (for instance) Finished without backlog. I am not overly concerned with the backlog status, just ‘Finished’.

[Sean_C.]

Hello,

This function is called by the Counter Read Buffer.vi. Each of the function parameters are listed and described in LabVIEW Help. This function monitors the task (referenced by "Task ID") and determines its state by querying the NI-DAQ Driver. This function does not cause state to change, it only monitors the state. The state of the task is dependant on the task's configuration. For finite buffered counter measurements, the state will be "running" until the specified number of counts has been acquired. For continuous, it will be running until instructed to stop with the Counter Stop.vi. The backlog is just a way of determining if all samples in the buffer have been read.

I hope this help. Please let me know if you have any further questions.

Regards,
Sean C.

[KirkSmith]

Thanks a million Sean. That was just the information I was looking for.