crichter

Thanks for your effort in replying. My problem is solved.

The attached VI works, but I feel there must be a smarter method of achieving the same result using the event structure. Also I have read that it is good to minimise local variables and property nodes. Guidance is appreciated.

Crude on-off event.vi

Thanks for the replies guys. drdjpowell, is my attachment correct? Reason I ask is it seems the tunnel went to "use default if unwired" automatically and I did not have to select it but usually I do.

Learn about timeout..vi

I saw a clever and fairly simple piece of code this morning, where code to update a graph was written in the timeout case of an event structure. (It ran on LV7.0 and drats!!! I failed to save it). The timeout case was wired to timeout after 100 milliseconds.  My question is, would not code such as I just described, defeat the whole point of using an event structure, since the while loop outside the event structure was running most of the time?  Am I missing something?

Ok. I am trying to learn from https://decibel.ni.com/content/docs/DOC-13297 and download the multiple data types queue variant.vi.  I am sure the up-loader posted the SubVI's. I am just at loss how to access them.

Further to my post above, if I click on "browse" or just wait, another window pops up titled "look in" which defaults to where I have all other VI's stored.  I assume I should be looking for a temporary file or folder. Not sure I would know what to do if I could find it.

I am having difficulty downloading example VI's which contain sub-vi's. I have always been able to acquire the main VI but all sub-vi's are missing.  During the process, I get a pop-up window with "Loading ...."

"Searching ......" an ignore button, a browse button and a stop button. I have always had this problem, but my need to resolve it has finally gotten greater than my embarrassment.

I thought I was pretty clever in overcoming the "wire is a member of a cycle" error. I had the desired continued count with sucessive presses of the run and stop buttons. Please see attached VI. Trouble is, after building in strings and arrays to try to make it into something useful, (see second attachment) the count is skipped occasionally. I assumed I had a timing error so I played with "wait until next mS multiple" without success. I also put a condtional loop on the stop button with "wait X mS" and experimented by varying X. To date, my problem persists. Comments and suggestions are welcomed.

continued count A.vi

Log File misses a count .vi

Thanks Guys. I guess I am weaning off the labview "milk" and tasting some meat.

Thanks DRJDPOWELL for posting the notifier example. How would I correctly stop this VI? I tried adding a "stop" event case and I think only the producer loop stopped. I also tried adding a "release notifier" outside the same while loop, resulting in an error 1.

Thanks for digging deeper for me Ravi. Unfortunately I cannot view the changes, as I only have version 7.0

That is a fair question Ravi. I wish view to the Y value at various values of X. Before my attempt to control the horizontal cursor, I could simply type my X value into the cursor legend and the the vertical cursor would snap to that value (e.g. 14.4). I would then have to drag the horizontal cursor to the intersection of the trace and the vertical cursor. If I choose "snap to plot" from cursor properties, both cursors will only snap to values I have put into an array.

I have graphs of (X,Y) cordinates (5, 0.19), (10, 0.38) & (20,0.78) respectively. In my VI labeled AA, the horizontal cursor tracks perfectly from 5 to 10 and not so well from 10 to 20. This is just as one would expect, since the slope from 10 to 20 has changed slightly. In vi labeled AB, I have made the code calculate the new slope and would expect correct tracking from 10 to 20. I was only able to achieve tracking by including a 0.4848 offset and even then it is not exact. A 0.38 offset might be understandable, but at present I cannot explain the error. I wish to understand this so that I can increase the complexity of my graphs and then experiment with "in range and co-erce". Any guidance would be much appreciated.

graph 3 points AA.vi

graph 3 points AB.vi

Sorry Ton. I don't understand what my "square block function" is.

Thanks Ton,

My intention is to have the string flash after a certain button is pressed. The user then inputs new data into the string and essentially presses an "enter" button which will stop the flashing.

Refering to the attached VI, please help me make my first while loop behave like the second, upon pressing of the booleon. The labview style guide says I should use "value change" in most cases. I have tried "mouse up" and "mouse down" to no avail. I have also tried all six options for mechanical action on the booleon and tried wait 50 mS instead of the "-1" on timeout.

Flashing string indicator1.vi

Guys,

Your replies are encouraging to me. Eric I cannot look at your attached file as I only have LV 7.0 but you must have done it well, since your file is 25k and mine 100k. Daklu, the user should be able to press a button to have the fluid forced back into the supply tank once the collect tank is full.

In the real life situation, nitrogen forces the fluid through and "rate" climbs rapidly just before the tank is full. The user must be ready for a rapid rate change and pull the bleed/blow-off valve. Then he presses a button to have the fluid flow back to the original tank. I could probably manage to simulate blow-off valve action on this VI.

Eric and Daklu,

Thanks for your prompt responses and advice.

Craig

My attached work in progress is a simulation of a pipe cleaning apparatus I use at work. This is neither homework, nor required for work. (I have not managed to generate enough interest in labview at work yet) My motive for designing this is to just improve my skills.

Once the supply tank is empty, and the collect tank full, I would like to be able to use booleons to make it run backwards. I feel I might be successful if I could get the tanks outside the for loops, but it seems they need to to be inside the for loops. I have had some practice using event structures but if I used event structures, the tanks would probably have to be outside them as well. Two questions: To solve my problem, should I study up on State Machines, or try something else? For Valves N1S1 & N2S2, I chose to use multi-state valves instead of two state valves, but I cannot tell the diference between the two. I tried my labview manuals. the forums and google for an answer but was unsuccessful. Please explain the difference between the two.

supply collect resized 5.1.vi

Thanks Jason,

Your advice worked like a treat.

I have superimposed three gauges programatically by wiring three postion property nodes together. Upon clicking "run", they are misaligned. I can align them manually, save my work then try again, and they still misalign. I checked sizing with the "set height and width" control, and all three gauges are the same wth a reading of 300. Please help me overcome this one.

reg test set 3a hands.vi

Problem solved, thanks to you both. It's great having people on board with knowlege like you have.

Thank You ShaunR. I reckon that is just what I needed to know.

I am still working on this one Shaun. I am using XP. Address bar shows C:\Documents and Settings\C.Richter\My Pictures before I right click on it. When I right click the address bar, I do not see an option to " edit address" but I only see 'Cut, Copy,Paste, Delete, Show unicode control, Insert unicode control. I guess I am one step closer, as I tried using "C:\Documents and Settings\C.Richter\My Pictures\MARS1 and this time got Error 7.

" Desktop/My Documents/My Pictures" isn't a real path. It's similar to a short-cut to a folder that changes with each user.

To find what the real path is you can open "My Pictures" in explorer and right click on the address bar. Then choose. "Edit address". The address bar will then show you the absolute path which will be something like C:\Documents and Settings\user name\My Pictures (XP) or C:\users\user name\My Pictures (Win7/Vista).

Thank You ShaunR. I reckon that is just what I needed to know.

I am seeking to open a jpeg file into labview 7.0. If I do not wire a file path, a dialog box appears for me to specify a file to read from. This works just as the user manual says it should. However if I wire my path to the VI

Desktop/My Documents/My Pictures/Mars1 ,this message pops up; "error 1 occurred at File/Directory Info in Check Path.vi>Read JPEG File.vi>Open a jpeg file.vi" I do have a picture of mars stored at Desktop/My Documents/My Pictures. Open a jpeg file.vi Please show me where I went wrong.