Numeric control outside limits

Hello,
I have a numeric control and I have set data entry llimits and selected coerce. It behaves fine using the increment/decrement buttons and when I type data in.
I want to be able to load a preset value read from a text file into the control . The problem is that using a local variable or property node to set the value the limits seem to be ignored.
Is there a way to update the control so it checks the limits or a better way of loading a preset value (the value will be different depending on the informtaion in the text file).
Thank you
Solved!
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Use "in range and coerce" before applying the value programmatically and handle exceptions as needed.
LabVIEW Champion . Do more with less code and in less time .

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How to create a numeric control (of any type) that can ONLY be increased or decreased by one 'unit' at a time?

As in the title. I wish to create a numeric control (no current limitations on its type) with a range of 1-10 (and a step of 1). The only difficulty I'm having is that the user must only be able to increase or decrease it by 1 at any time. The code initiated by this value change must have completed at least once before the value can be changed again. This is because the VI's code is mostly contained in a while loop, and the control is read once every iteration and its last value must not differ by more than 1.
Is this possible with LabVIEW 6.1 and if so, how?
One of the solutions I've come up with so far is to disable the control immediately after it's read, and to enable it again immediately before it's read for the next time (I have to assume that the user is unable to click twice before the control is disabled). Is this an acceptable method or is there a better way?
I also had an idea of partially disabling a normal numeric control such that it could not be typed in - only the arrows remained operational. However, i don't know quite how to do this.
James
Never say "Oops." Always say "Ah, interesting!"
Solved!
Go to Solution.

Yes, i realize my solution needs the idea that followed it to be feasable in order to work properly. My bad!
I did wonder about using a combination like that, but I hoped it could all be done with one object. Ah well - just means adding an extra little bit of code. No probs.
Thank you anyway.
Never say "Oops." Always say "Ah, interesting!"

Numeric control error handling

Hi all,
I have two question about numeric control.
1) "How to handle invalid inputs?"
Let say, I have one numeric control that can only accept 0 to +inf (Range). So negative input will be invalid data input. Whenever I typed the negative value on it, this control automatically changed back to default (min) value. What I want is that. Is there anyway to detect invalid user input? So that I can program whenever user input negative number, it will automatically change back to previous valid input (not default value).
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I used property node to assign the range but my problem is that. I assigned min 0.1, max 1.2 and increment 0.1 but I cant able to select 1.2 or sometime 0.1 by using increment/decrement arrow. Maybe because of floating points? And also I want to do when user input overrange value (eg.1.3) by typing, the value should go back to previous valid input.
Any idea? Thanks

You can choose how LV will react on entries exceeding a limit. The default is, that LV coerces the value to the limit. But you can also ignore the limit and the user can enter any value.
Nevertheless, if you ignore the limits, you always have to check in your software for invalid values!
Regarding 2) i couldn't reproduce what you described. Maybe you should post a little example....
For the 2nd part of your question, please see my answer above...
hope this helps,
Norbert
CEO: What exactly is stopping us from doing this?
Expert: Geometry
Marketing Manager: Just ignore it.

Update while typing in numeric control?

So...
When I type a number into a numeric control, it doesn't update until I hit enter or click somewhere outside the control.
Problem is, after entering the number, I want to click on a "go" button
to do something with the new value in numeric control, but unless I
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This gets aggravating.
How to make sure the value of the numeric control gets updated before doing something with it?
"update while typing" exists for string controls, but seems conspicuously lacking for other types of controls...

I cannot reproduce your described behavior: With either a local variable or the numeric control inside the event case, I never see a stale value. Please attach your VI so we can troubleshoot.
Adding a delay to fix something like this is incorrect and dangerous. If a delay solves the problem, it points to a flaw in the code. What if somebody will run your program on a slower computer where it would suddenly need a 12ms delay. You'd be back to sqaure one, dealing with race conditions.
(And why are you using "mouse down" instead of "value changed"?)
Message Edited by altenbach on 03-21-2006 05:22 PM
LabVIEW Champion . Do more with less code and in less time .
Attachments:
Events.vi ‏12 KB

Setting Range for a Digital Numeric Control

Hi,
to control the numeric range of my Numeric Controls i wants to read the
limits from an ini-file. To this point no problem. But how can i set the
minimum and maximum values to the control? I created an attribute node,
but there is no range property avaible?
Is there a way to do that?
regards
Henrik

Thanx, in the next weeks i will start with 6i and so i will wait.
Henrik
Greg McKaskle wrote:
>
> > to control the numeric range of my Numeric Controls i wants to read the
> > limits from an ini-file. To this point no problem. But how can i set the
> > minimum and maximum values to the control? I created an attribute node,
> > but there is no range property avaible?
> >
> > Is there a way to do that?
> >
>
> If using LV6, the attribute node has properties for min, max, incr, and
> range mode. Previous versions didn't; so can do the feedback and
> filtering on the diagram, but not by setting properties/attributes.
>
> Greg McKaskle

Invalid input event for numeric control

Need to catch the event when invalid input being through out, customer doesn't like the notify.
George Zou
http://webspace.webring.com/people/og/gtoolbox

I haven't had a big problem with this, and I plan to continue to use numeric controls instead of making everything strings, but it does seem strange that CVI doesn't catch this. I like the automatic range checking options, the programmable increment/decrement buttons, and the ease of use.
You can use a quirk in CVI to catch this: if you enter an invalid number like 1.2.3 or 3...14159 or 1-2, CVI triggers EVENT_VAL_CHANGED, but leaves the original number unchanged. So you can create a case in the callback for the numeric control for EVENT_VAL_CHANGED, and in that case check to see if the value is the same as the previous value. If it is, assume an invalid input. EVENT_VAL_CHANGED does not get fired if you just press Enter without changing the value.
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TestInvalidInput.zip ‏6 KB

How to Define Limit to Numeric Control

Dear all,
I am controlling a motor which is pressing to load cell. I am controlling the motor position with a numeric controller in the front panel, the question is when i accidently enter a large value(undesired motor's new motor position), than it could damage the load cell.
In this case : Can we arrange a numeric control in the front panel so that it can accept numbers only between "0" and "10".
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Kind Regards,
Best Wishes.

Right click on your numerical control, go to properties, click the 'Data Entry' tab. Un-tick 'Use Default Limits'.
You can now set Minimum, maximum, Increment etc.
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Attachments:
dataentry.png ‏41 KB

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Hi,
I'm developing an application that has a panel with black background and green or red numbers. I've added numeric controls and configured the text color and text background color attributes accordinglingy. I set the numeric control to hot or validate control mode and show the inc/dec arrows, since I want to be able to incr/decr the numbers.
The problem is that when I run the application and I hit the inc/dec arrows, then the colors inside the numeric control frame become inverted: the black background becomes white and the green number becomes cyan. I've created a callback function assosicated with the numeric control and tried forcing the text and background color, in the EVENT_VAL_CHANGED section, using the SetCtrlAttrribute() function, but to no avail. Also added ProcessDrawEvents didn't help.
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I want it to keep its original colors at all times, even when I'm clicking the incr/decr arrows...
Kind regards,
pgriep
Solved!
Go to Solution.

Ok, now I see what's happening.
The effect you are seeing is a resul of standard numeric control behaviour combined with the black bcakground: when you use arrows to increment/decrement a numeric control its value will be automatically highlighted; on the default background you'll see the white area and figures highlighted in black (white numbers on balck background). If you set the background to black the system will automatically change the colors used to highlight the text, and that's what you're seeing.
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"I've always wanted to be the first to discover a bug in a new LV release! "
Thank you for sharing that with us. You are helping to make LV even beeter than it is.
regarding your quote "I've always wanted to be the first to discover a bug in a new LV release! "
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How can I highlight the default data in a numeric control when a VI loads.

I have a VI that features a string constant that asks for a numeric response via a numeric control, a "next" button that enters the data (controlled by the enter key), and two leds, one that lights if the data entered is correct, and one that lights if the data entered is incorrect. Is there anyway that I can make sure that when this VI loads, the zero in the numeric control is highlighted?
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If you set the key focus of the control to true (Right click on
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Can you use the value from a numeric indicator in a numeric control?

Hi!
I have to develop a code where I have to find the maximum value of a waveform and draw a line at 50% of the value. So I chose to find the amplitude of say 10 cycles of waveforms and found the maximum value out of the amplitudes.
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Solved!
Go to Solution.

Hi!
Thank you very much for taking some time out. I have been trying to do this since 2 months and I am stuck right where I am.
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amplitude display.vi ‏217 KB
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Programatically bring the cursor to a numerical control while VI running

Does anyone know how to programatically move the cursor to a particular numerical control while a VI is running?
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I have set up a separate key navigation for thenumerical control in question, so if the user presses the Esc key, this control becomes active and the cursor is in place, but I would like to move the cursor there without this extra user button press if at all possible.
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Will
I'm not sure if this is what you are looking for but it might do what you need.
On the block diagram right click the control in question >>create>>property node>>key focus. Now right click the property node and select Change to write. Wire a boolean true constant to it and place this snippit in the appropriate place(s) in your code depending upon your architecture.
Hope this helps.
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Default value of a numeric control

Hello I want to fix the default value of a numeric control using his node property but I haven't found this attribute. It's possible to fix this value through the node property of a block?
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The default value is only relevant when the VI is loaded into memory, not every time you start running it. Your code is probably changing the value to some out-of-limit value (probably 0 if your calculations are incorrect) and it is coerced to the minimum. If you want a value to remain constant, don't change it.
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In addition, I suggest you read the LabVIEW style guide and the LabVIEW user manual (Help>>Search the LabVIEW Bookshelf).
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With Traditional NI-DAQ Compatibility VI's the acquisition locks when I press the increment or decrement button of a numeric control.

Hello all.
I´m using a PCI-6220 and the Traditional NI-DAQ Compatibility VI's to make the acquisition that is in the attached VI. But when I click the increment/decrement button on the numeric controls my acquisition stops. In the same PC I made the same experience with a 6040 and I could not see this problem. I tried with the PCI-6220 with the DaqMX VI's and I could not see this problem too, for these reasons I believe that the problem has something to do with the Traditional NI-DAQ Compatibility VI's.
I built machines that can have one or the other board (depending if it is low-end or normal). Does somebody knows the solution for this problem?
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Attachments:
experiencia.vi ‏49 KB

Hello
For what I’ve seen on National web site, using the “Traditional compatibility VI’s”, it sould be possible to control a NI-DAQmx using code written in NI-DAQ Traditional. This information was obtained from the following NI link:
http://digital.ni.com/softlib.nsf/954feaeea92d90918625674b00658b83/9d67f671bcc6850586256e630059308b?...
Please read this information and then tell me something please.
Best regards!

The acquisition locks when I press the increment or decrement button of a numeric control

Hello all.
I´m using a PCI-6220 and the Traditional NI-DAQ Compatibility VI's to make the acquisition that is in the attached VI. But when I click the increment/decrement button on the numeric controls my acquisition stops. In the same PC I made the same experience with a 6040 and I could not see this problem. I tried with the PCI-6220 with the DaqMX VI's and I could not see this problem too, for these reasons I believe that the problem has something to do with the Traditional NI-DAQ Compatibility VI's.
I built machines that can have one or the other board (depending if it is low-end or normal). Does somebody knows the solution for this problem?
Thanks in advance.
Paulo Carmo
Attachments:
experiencia.vi ‏49 KB

Hello
For what I’ve seen on National web site, using the “Traditional compatibility VI’s”, it sould be possible to control a NI-DAQmx using code written in NI-DAQ Traditional. This information was obtained from the following NI link:
http://digital.ni.com/softlib.nsf/954feaeea92d90918625674b00658b83/9d67f671bcc6850586256e630059308b?...
Please read this information and then tell me something please.
Best regards!

Numeric control outside limits

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