Can I have the user enter a variable to be used in Signal Express?

[jonrie1]

We are looking to use Signal Express to collect data from load cells and analog sensors. We would like the user to be able to enter a variable that the Signal Express program can act on. Is this possible within Signal Express?

[ColeTrain]

Hello jonrie1,

There absolutely is a way to get user input.  To use it, go to the menu View»Operator Interface.   You can place down a few different items for user input in the operator interface.  Once you have them placed, you can link their input to where you want them in your program.  If you do a search in the Signal Express help for "Operator Mode", the second result has all the info you should need.  Just post back if you have something more specific that you're having problems with.

[jonrie1]

Hi. I've added the operator mode control (in my case a numeric operator called Area). I would like to use this area value in a calculation. In my app I have some analog values coming in and I do some filtering and a formula to scale the values correctly. I want to divide the newly scaled values by this area operator.

I selected the Edit Bound Parameter on the numeric operator, and what I see are the DAQMX Acquires, and the filter operations. It's not very clear how to get the area to show up as something I can divide by.

Can you help?

[Jordan F · Accepted solution]

Hi, 

When you select "Edit Bound Parameter", it will populate with all step parameters that are supported for the given control used.  Not all steps or step parameters are able to be adjusted when the operator mode is enabled.  That is why you only were able to bind the controls to the DAQmx Acquire and Filter step (they are the only steps paramters available to bind in your setup).  The forumla node is not able to reference a control input from the operator interface. You have to manually configure the formula in the step setup tab for that specific step.  

I would recommend if you desire a more customized user interface and programming approach to use an Application Development Environment.  Signal Express is great for acquiring signals and performing basic processing and analysis but if you desire more functionality than LabVIEW would be a better option.   

[Jordan F]

Actually, I just found another way that you could perform this task when using the formula node.  What you have to do is create a DC analog signal, bind the variable to the offset parameter and then implement this into the forumla node.  I attached a screenshot below for your reference.  You will have to enable the created DC waveform in the formula node to reference.  Hope this helps! 

Message Edited by Jordan F on 10-21-2009 04:42 PM

[jonrie1]

Related to this, is there a way to display the analog value as a numeric display, vs relying on the graph?

[ColeTrain]

Hello jonrie1,

We can do this, but not through the operator interface mode.  If you just want to see the latest value of a DAQmx aquire task, then you can view the step setup of the task when you're running and change the display type to a table as shown below.

[jonrie1]

I understand what you are saying, but this would not be sufficient as I take the values from a DAQmx aquire steps and process them individually with filters and formulas to get the "calibrated" output. My last block has 8-10 of these values sent to an Excel file (as csv text). It would be really handy to also display the values as a numeric so the operator can see how it is running before or as the system is collecting data in Excel, without have to collect a bit, then stop it and open the Excel and confirm the results are as desired.

Let me know if you can think of a way to do that. In the mean time I might try to develop it in Labview and save as an executable.