Storing a reading as a constant

[kmhijazi]

Hello Everyone,

This question may sound silly but here it goes:

I am developing a program that will trigger static creep loading on a specimen using a load cell and a linear actuator.

So far I was able to get the whole program done and I am stuck at what I believe to be the last obstacle, the process of applying creep to the specimen.

For those who have no background on what static creep loading is, it is basically keeping the load constant over a certain period of time, and I developed a program that is able to trigger creep but I want to get the value of the load (at which creep is triggered) and save it as a constant variable. So far I am not sure how I can do that?

Can you guys help me with that ASAP?

[James.M]

We need more information in order to help you. I'm not sure if you're asking just a basic LabVIEW question regarding saving a value from iteration to iteration, or if you don't know how to communicate with your device.

You say "last obstacle", except it kinda seems like you said "I need my application to do A and B, but I'm stuck on A and B."

It would probably be easiest if you share your code as it is now. DO you have a load reading coming in? Do you have an output to control how the load is applied?

[kmhijazi]

This is a project I have been working on for the last few months, and the question is more into Basic LabVIEW, I was just trying to give you a little background. By last obstacle, I meant that I was able to write the code for the linear actuator control, reading data from the load cell and the optical encoder and writing a stable program in general (since I am a beginner that is a big thing for me). For legal and copyright issues, I can't upload the code for now. But I can describe the particular situation: This program is supposed to stop the motion of the linear actuator at a certain point during mechanical stretching of a specimen. The load reading is now kept under check and if the load decreases (stress relaxation) then the linear actuator is supposed to move as to apply load up until the load reading returns to that specific point. and that is the issue, I need to get the reading at the point at which creep was triggered saved as a separate constant variable. That is what I am struggling at, I want to know if there is a method, through which I can save a load reading to be used as a CONSTANT reference?

[kmhijazi]

p.s Thanks in advance for your help 🙂

[James.M · Accepted solution]

This is all very basic functionality that you will just learn as you use LabVIEW more. If you are storing a value from loop iteration to the next, you can use something called a Shift Register to store that value. There are many different ways to work with shift registers to get your desired results (and there are also other ways of doing it outside of shift registers).

You really should watch some tutorials and try some examples to get a feel for basic programming practices and software architectures to follow. 

Here are some free training tools primarily focused on LabVIEW and NI hardware to help get started.

NI Learning Center

NI Getting Started

-Hardware Basics

-MyRIO Project Essentials Guide (lots of good simple circuits with links to youtube demonstrations)

-LabVEW Basics

-DAQ Application Tutorials

-cRIO Developer's Guide

Learn NI Training Resource Videos

3 Hour LabVIEW Introduction

6 Hour LabVIEW Introduction
Self Paced training for students
Self Paced training beginner to advanced, SSP Required
LabVIEW Wiki on Training