IviDigitizer Query Min Waveform Memory
IviDigitizerBase Capability Group
This VI is used to determine the minimum amount of memory that is needed to fetch or read data from the digitizer with maximum performance.
The returned value includes the memory needed to handle DMA alignment issues and any internal memory that is used by the digitizer hardware or the driver.
The parameters to this VI are similar to the parameters used in Read and Fetch VIs. Users should call this VI before allocating data buffer memory, and then call a Read or Fetch VI with the same parameter values.
 |
Note This VI will return a value that can be used to allocate the optimally-sized memory buffer for Read and Fetch calls with the same passed parameters. If the Read and Fetch calls specify fewer data points, the data buffer will still be large enough and no performance penalty will be realized (aside from wasted memory space). If the Read and Fetch calls specify more data points they will simply fill the allocated memory buffer as fully as possible. Subsequent Fetch calls can then be made to retrieve the remaining data. |
 |
Offset Within Record (0) Specifies the start index within the record from which the data should be retrieved.
Unit: volts Default Value: 0 |
 |
instrument handle Returns an Instrument Handle that you use to identify the instrument in all subsequent instrument driver VI calls.
Notes: (1) This VI creates a new session each time you invoke it. This is useful if you have multiple physical instances of the same type of instrument. (2) Avoid creating multiple concurrent sessions to the same physical instrument. Although you can create more than one IVI session for the same resource, it is best not to do so. A better approach is to use the same IVI session in multiple execution threads. |
 |
Data Width (Real64) Specifies the size of the sampled data that will be retrieved. The value of this parameter must be 8, 16, 32 or 64, corresponding to the intended Read/Fetch VI.
Valid Values: Int8 - 8 Int16 - 16 Int32 - 32 Real64 - 64 Default Value: 64 |
|
Number of Records (1) Specifies the number of records that will be read.
Default Value: 1 |
 |
error in (no error) The error in cluster can accept error information wired from VIs previously called. Use this information to decide if any functionality should be bypassed in the event of errors from other VIs.
The pop-up option Explain Error (or Explain Warning) gives more information about the error displayed. |
|
Numer of Points Per Record (256) Specifies the number of data points to return.
Default Value: 256 |
 |
instrument handle out Returns an Instrument Handle that you use to identify the instrument in all subsequent instrument driver VI calls.
Notes: (1) This VI creates a new session each time you invoke it. This is useful if you have multiple physical instances of the same type of instrument. (2) Avoid creating multiple concurrent sessions to the same physical instrument. Although you can create more than one IVI session for the same resource, it is best not to do so. A better approach is to use the same IVI session in multiple execution threads. |
 |
Numer of Samples Returns the minimum buffer size in samples needed for a subsequent Read or Fetch call with the same readout parameters. |
 |
error out The error out cluster passes error or warning information out of a VI to be used by other VIs.
The pop-up option Explain Error (or Explain Warning) gives more information about the error displayed. |