Academic Company Events NI Developer Zone Support Solutions Products & Services Contact NI MyNI
1 ratings:
 5 out of 5     Rate this Document

How to do a Null-Offset Calibration for Full-Bridge Absolute Transducers (SCXI-1520 / PXI-4220) with the DAQ Assistant?

Primary Software: Driver Software>>NI-DAQmx
Primary Software Version: 7.1
Primary Software Fixed Version: N/A
Secondary Software: LabVIEW Development Systems>>Base Package
Hardware: Multifunction DAQ (MIO)>>SC Series>>PXI-4220, SCXI>>Modules>>SCXI-1520

Problem:
The DAQ Assistant does not provide a way to do any calibration for Full-Bridge Absolute Transducers that are not strain gauges (for example load cells) for a NI-DAQmx Tasks / Global Channels created in MAX.

If I use the example VI located in the example finder ( Browse According to Task » Hardware Input and Output » NI-DAQmx » Analog Measurements » Strain » Acq Strain Samples (with Calibration).vi ) the values are not stored on the Task / Global Channel and I need to calibrate every time.

Is there any way to store the calibration values in the Task / Global Channel created in MAX?

Solution:
If the Task / Global Channel had been done with the DAQ Assistant (MAX) it is not possible to create and store the values of a Shunt calibration. But it is possible to do a Null-Offset calibration.

You have to use the Perform Bridge Offset Nulling Calibration VI that is on the NIDAQmx function palette and save the current Task / Global Channel.

If you want to save the values of a Shunt calibration you cannot use the DAQ Assistant. So you should create and save the Task / Channel programmatically in LabVIEW and you cannot edit it with the DAQ Assistant.

Attached are two VIs that can be used to perform a nulling-offset calibration storing the values of that calibration in the respective Task / Global Channel. They can be used as subVIs in your application.

Related Links:
KnowledgeBase 2I7EBBJ3: Measuring a Full-Bridge Absolute Transducer with the SCXI-1520 or PXI-4220
KnowledgeBase 3DJAN7NS: How do I Configure a Load Cell in MAX?

Attachments:


DAQmx_Task_Null_Offset_Calibration.viDAQmx_Global_Channel_Null_Offset_Calibration.vi


Report Date: 03/27/2006
Last Updated: 04/07/2006
Document ID: 3VQ9BUMK

Your Feedback! poor Poor  |  Excellent excellent   Yes No
 Document Quality? 
 Answered Your Question? 
  1 2 3 4 5
Please Contact NI for all product and support inquiries.submit