Measuring Strain with SCXI-1520

NOTE: It is suggested that virtual channels are used to acquire information from the SCXI-1520. Values can then be acquired using a simple analog input example. Properties such as excitation, filter settings, shunt resistor values, shunt calibration, null offset, etc. can be set in Measurement and Automation Explorer (MAX). The purpose of the following example is to demonstrate how to perform shunt calibrations and null offsets programmatically.

DESCRIPTION:
This VI shows how to use the SCXI-1520 module to measure data from strain gauges. It also shows how to programmatically perform a null offset and shunt calibration on the strain gauges. The acquisition takes place in a loop that runs until an error occurs OR the stop button is clicked. This is a timed acquisition, meaning that a hardware clock is used to control the acquisition rate for fast and accurate timing. It is also a buffered acquisition, meaning that the data is stored in an intermediate memory buffer after they are acquired from the DAQ board. Once the data has been acquired, LabVIEW retrieves the data from that buffer, processes it, and displays it.

INSTRUCTIONS:
1. Enter the device number and the channels you intend to scan.
2. Select the input limits that pertain to your sensor(s), if the default values configured in the Measurement and Automation Explorer (MAX) are not suitable.
3. Enter the filter and excitation values you want for your strain gauge(s).
4. Enter the value of the resistor(s) you are using for shunt calibration (you should use the SCA terminals for all your shunt resistors). Ignore if you do not intend to perform shunt calibration.
5. Enter the gauge resistance, gauge factor, and bridge type of the strain gauge(s) you are using and the Poisson ratio of the surface on which they are mounted.

NOTE: All the above controls MUST be set before the VI is run.

6. Run the VI.

Requirements

Filename: scxi-1520_strain.vi

Software Requirements

Application Software: LabVIEW Full Development System 6.1
Language(s): LabVIEW

Hardware Requirements

Hardware Group: Multifunction DAQ (MIO)
Driver: Traditional NI-DAQ (Legacy) 6.9.0

Reader Comments | Submit a comment »