Read value from slider when mousebutton is released

[Little_Helper]

Hi

I have got a stepmotor with an encoder to which i send a string command with VISA write through the COM port. The string I send is an integer value that I read from a slider from e.g. 10-30. The problem is that LabView sends the command right away I start moving the slider, but I want LabView to send the value first when I release my mousebutton on the given number on the slider, is this possible to do?

If LabView sends the command too fast I cannot be sure that the motor will receive the latest command, and therefore it will stop in the wrong position.

Simon

[TiTou]

Hello,

Are you using an Event structure to detect the value change on the slider and then send the command with the new value to the motor ?
I guess yes... On string controls there is an option that you can enable or disable "update while typing", I wish we could have the same option on sliders "update while dragging" that we could enable or disable.
As far as I know it does not exist in LV 8.20, maybe it does in LV 8.50. Otherwise, it can certainly be done with an Xcontrol, but I'n not really familiar with these.

Good luck and happy wiring new year 😉

[rpursley8]

Instead of using the Value Change event, you should use the Mouse Up event.  When that event occurs just read to current value of the slider.

[TiTou]

I thought of that too but it's a bit anoying because if the pointer of the mouse in not over the slider when you release the mouse button then the event is not detected even if your value has changed.
It might be better to set the event structure to detect any mouse up event and then send a command to the motor only if the slider's value has changed since it was last sent to the motor.

hope this helps

[rpursley8]

That might be the easiest.  It could get fairly complicated otherwise.



Message Edited by rpursley8 on 01-09-2008 08:09 PM

[TiTou]

Hello,

Here is a bit of code that kind of meets the requirements, I don't really like it because I think it's too much code for such a basic feature, but at least it works...

Hope it can help someone until LabVIEW team add the possibility to disable the update slider value while dragging

[TiTou]

I keep thinking something better can be done but here is a better implementation (still not perfect because using a local) I received from NI support.

😉