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hello

my self abdul ...i need help please help me out ...

i want to read current values with step  size of 0.1 voltage till 5 volt from laser diode driver(FL500) via USB 6009 ...so please ... can any one tell me the connection to read current values i.e on x-axis volatge and y-axis current as ouput.

and here i am attaching my programe which i try to read it but i was falied to do it...waiting for reply

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Message 1 of 52
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Hi raoof,

 

but i was falied to do it..

Where exactly did you fail?

 

- What is the difference in your calculation of "c" and "st", so you need to calc them both?

- Why do you use a While loop instead of a FOR loop?

- Why do you read 1000 samples for each voltage setting?

- What is your task definition? Your subVI is missing…

- How did you wire your current? The USB6009 is not capable of measuring current directly…

- Why do you use the DAQAssistent instead of plain DAQmx functions as you did for reading the AI channel?

Best regards,
GerdW


using LV2016/2019/2021 on Win10/11+cRIO, TestStand2016/2019
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Message 2 of 52
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hello Gerdw sir

1) i failed to get output of current verses voltage

2)c is variable and st is step here to stop my step when it reach to 5 v

3)for continous itteration ...as need to read volatge with step of 0.1 till 5 v

4)just i give 1000 samples to read but it can be change .

5)my task defination is to read current of laser diode driver via USB6009 . and here i was provided with dammy laser diode with 10 ohm resister...so i need to get my output current and volatge values in graph  with step of 0.1 till 5v as i am giving 5 volt from power supply..i  will attach my vi

6)accroding to my knowledge sir in DAQ assistant we can not define our respected values so i use DAMmx ...

sir please can you tell the connection

Download All
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Message 3 of 52
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Hi raoof

 

Can you please attach the "my voltage 1.vi" that you are using as a SubVI?

 

Thank you,

CorinneD

 

Corinne Doppmann
Application Engineer
National Instruments
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Message 4 of 52
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hello i am attching my sub vi file please look it and give solution for it waitng for your positive reply

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Message 5 of 52
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Hi raoof

 

I'm sorry, I do not really understand what you are trying to do in the newest version of "my voltage task.vi" that you posted.

The vi is currently doing two things:

The while loop with the DAQ Assistant will continuously read out the "Voltage" channel between 0V and 5V and plot the read values in the Waveform Chart.

The two while loops are completely independent to each other.

The upper while loop, where you calculate c and st will allways plot a sinusoidal.

 

I think the old version of "my voltage task.vi" was closer to what you were trying to do.

As far as I understand you want to create an IV plot where you sweep from 0V to 5V and read out the corresponding current values.

 

Could you please tell me, how you want to measure the current? Because the USB 6009 only has analog voltage inputs, so you somehow must convert your current measurement to a voltage measurement. 

 

In order to create the IV plot you only should have one while loop with three steps:

1. Write out a voltage value

2. Wait for your system to settle

3. Measure the corresponding current

You were doing these three steps in the old version of "my voltage task.vi"

I think your main problem is the third step: to measure the corresponding current.

To find out what the problem is, I would need more information on the "my voltage 1.vi" , which probably isn't doing what it should.

And you should probably convert the measured voltage to the current value somehow, depending, on how you measured the current in the first place.

 

The way you create the XY Graph after the while loop should be correct. 

Best regards

CorinneD

Corinne Doppmann
Application Engineer
National Instruments
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Message 6 of 52
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hello

i want to get VI (voltage and current) graph.. with step of 0.1 V using muti power supply of 5 V via usb 6009...plaese can any one help me out  with the connection ...

and please check my prorame which i a m attching here ...and also my experiment picture which i am working.

thanks

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Message 7 of 52
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Hi raoof,

 

using muti power supply of 5 V

What is "muti power supply"???

 

please check my prorame which i a m attching here

You only read a single AI channel.

You don't output any voltage values.

You use a single X value with 1000 y values for your graph.

You do reading the DAQmx channel in a loop, but the graph is made outside the loop.

You only use the values of the last iteration to create a plot.

 

Best regards,
GerdW


using LV2016/2019/2021 on Win10/11+cRIO, TestStand2016/2019
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Message 8 of 52
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hello

thanks sir for replying me soon

muti power supply is power supply where i am giving 5V to laser diode driver..

and sir i didnt get your programe please send me once....

can you show me in detail how to read current values...........waiting for reply

thanks#

 

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Message 9 of 52
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@raoof wrote:

and sir i didnt get your programe please send me once....

can you show me in detail how to read current values


He didn't send you a program.  He told you what you need to fix in yours.

 

The best way to read current is with a little Electrical Engineering inginuity.  Ohm's law states that the voltage drop across a resistor is V = I*R.  So to measure current, you can measure the voltage drop across a resistor.  I = V/R.  They make really small resistors specifically for this purpose.  You should use a differential measurement when doing this.


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Message 10 of 52
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hello

i understood that i can use ohm´s law ....and also i have 10 ohm resister which is attach to my laser diode driver ...but my question is how to volatge vs current graph ...with step of 0,1 V....using usb6009  here you can see my graph which i am trying to get.....

thanks10917575_786157831438464_1478626719_n.jpg

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Message 11 of 52
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hello

i am sending picture ,,please telll me how to get ouput graphUnbenannt.png

thanks

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Message 12 of 52
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Hi raoof,

 

my question is how to volatge vs current graph

These steps are required:

1 output a voltage

2 read the corresponding voltage across your resistor and calculate the current

3 back to step 1 for all voltage steps

4 display all current vs voltage values in a XY graph

Best regards,
GerdW


using LV2016/2019/2021 on Win10/11+cRIO, TestStand2016/2019
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Message 13 of 52
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hello

i got 001.5 mv as ouput...?is that right??

how i can get corresponding  volatge valuses  across resistor  sir????

so plot currnet vs voltage

thanks

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Message 14 of 52
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You have to vary some voltage source as an input.  You measure the current by measuring the voltage drop across the resistor.  So for each set voltage, you have a current.  Build those numbers into two arrays (one for voltage and one for current) and use an XY graph to create your plots.

 

1.5mV across a 10 Ohm resistor would be 150uA.  How much current are you expecting?


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Message 15 of 52
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hello sir

how i can vary volatge ....?because i given 5V FROM POWER SUPPLY ,,how can i vary it..and where i should  read volatge drop ...as i am not able to see my multi meter please send me 2 array program sir.

thanks

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Message 16 of 52
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How do you expect to do an IV curve when you can't set the voltage?  How do you tell the driver what voltage to put out?


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Message 17 of 52
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I really think you have to back to square one and define your requirements before attempting anything else.  From what I've read, you don't really know what you want to do, how to do it, or with what instrumentation.

Bill
CLD
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Proud to say that I've progressed beyond knowing just enough to be dangerous. I now know enough to know that I have no clue about anything at all.
Humble author of the CLAD Nugget.
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Message 18 of 52
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hello

sir i am cofused ...i have 5 v ..but i am not able to vary please tell me how i can vary this 5 v which is constant ......

and can i get  your skype id ..which will be more more easy to tell you and get my solution please help me out...as i am new to labview this is my frist time using labview ......hope for the best

thanks

 

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Message 19 of 52
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billko is right here:  the help you actually need right now has nothing to do with LabVIEW.  Your problem is you don't even know what you are trying to test.

 

So from I have been able to gather here, the goal is to perform an IV curve.  What device is this curve supposed to be done on?  If you are doing an IV curve, you need a supply that you can vary, preferably via serial port or USB (so that we can control it in software).  The measure current, you will have a 10 Ohm resistor in series that you can measure the voltage drop and derive the current.

 

So let's try to get that setup before we start doing anything with code.


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Message 20 of 52
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hello billko

1)i am trying to get graph of volatge vs current characteristics by supply 5V from multi power supply (MPS 7106) .

2) the device i am using is laser diode driver FL500.

3)i dont have any serial port but i have USB 6009.and i dont have varying source ..my professor told me to get vi graph using  this equipment.

4)i have laser diode driver which has dammy of laser diode and 10 ohm resistor attach...and i connected vs=5v to muti power supply and but i am confused where i sholud connect my vset in usb 6009(whether in input side or output side)....

i am attching my experiment picture please look it ..

thnaksUnbenannt.png

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Message 21 of 52
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this my muti power spply picture photo.php.jpg

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Message 22 of 52
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Seems to me you have to take care of the hardware setup before you can do anything else.

 

Your professor wouldn't leave you hanging like this.  He wouldn't just dump a bunch of junk on your desk and say, "here, have at it".  Unless the exercise is to demonstrate what you know of electronics?

Bill
CLD
(Mid-Level minion.)
My support system ensures that I don't look totally incompetent.
Proud to say that I've progressed beyond knowing just enough to be dangerous. I now know enough to know that I have no clue about anything at all.
Humble author of the CLAD Nugget.
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Message 23 of 52
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hello

thnanks .you ...i will try my best ..

 

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Message 24 of 52
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Don't be afraid to post back when you have the hardware sorted out.  This just isn't the best place to ask for hardware setup.  🙂

Bill
CLD
(Mid-Level minion.)
My support system ensures that I don't look totally incompetent.
Proud to say that I've progressed beyond knowing just enough to be dangerous. I now know enough to know that I have no clue about anything at all.
Humble author of the CLAD Nugget.
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Message 25 of 52
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hi

ok thanks.......i will ask when i finished my hardware part ..thnanks for your time

regrads

abdul

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Message 26 of 52
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The 6009 has an analog output. Why aren't you using that for the source?
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Message 27 of 52
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@Dennis_Knutson wrote:
The 6009 has an analog output. Why aren't you using that for the source?

That's find as long as the device needs less than 5mA of current.  If more is needed, then we need to start talking about op-amps and voltage follower amplifiers.


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Message 28 of 52
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Sorry, forgot the low current output. Still, with an amplifier might be only option if the dc supply mentioned is not programmable. A quick search for the model number did not turn up anything useful.
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Message 29 of 52
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Moving the discussion back here from the other thread:

 

Please tell us who makes the laser diode driver. If possible post its specifications or manual. IF you can do what you are trying to do with the equipment you have, this driver will be the key. Since we do not know anything about it, we cannot advise you.

 

The key to making any program, whether written in LabVIEW or not, is understanding in detail how to do the tasks required. For your V-I charactersistic project you need to knwo how to set the voltage or current applied to the laser diode (or dummy). Until you know how to do that - MANUALLY - you cannot begin to determine how to do it programmatically.

 

Lynn

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Message 30 of 52
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hello

ohh thanks for reply...i am using laser diode FL500 which has 2 output one is vs =5v and other is vset here i am confused...

what i try was i pulg vs output to USB6009 output pin is that right?...and vset connected to usb6009 input in ai0 port ...but know i am confused to get ouput here ,,....reply please ...i am tried as working so long on it

thanks

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Message 31 of 52
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this is datasheet for laser diode....

thanks

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Message 32 of 52
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Vset is an INPUT to the driver.  It claims a 2kOhm impedance and states not to exceed 2V on that input.  So that puts the current at 1mA.  An analog output of the DAQ can handle that.  So connect AO0 to Vset.  You will use LabVIEW to set that voltage.


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Message 33 of 52
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You still have not explained anything about how you are going to vary the dc in. If you can't do that, it makes no sense to try to plot the current. Attach a schematic of your setup. The design of your system would be an obvious first step.
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Message 34 of 52
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Sorry, posted before you attached pdf.
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Message 35 of 52
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HELLO

who to vary volatge that my confusion .....see my vi which i tried ... ia m attaching here...

when i conect vset to USB 6009 its show error regarding volatge vlaues

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Message 36 of 52
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What does the error actually say?  Does it have an error number associated with it?

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Message 37 of 52
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this is error....iam attaching now

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Message 38 of 52
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What error are you getting?

 

Why are you using the Formula Node?  What is the sin function doing in there?  There is a nice simple function in LabVIEW called Ramp Pattern.vi (in the Signal Processing->Signal Generation palette).  Use that to make an array of the step voltages and then use a FOR loop with autoindexing to set the voltage.  Makes things a lot simpler.


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Message 39 of 52
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Well the sine of i*Step will vary from -1 to 1  Your task range is 0-2 so half of any possible values of "c" will result in an error


"Should be" isn't "Is" -Jay
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Message 40 of 52
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hello

i am using formula node to get volatge in step of 0,1 ..as my volatge range is 0 to 5 v ...

and sin it was my mistake there is no sin ...

ok i will try to do with your send vi and tell my result

thanks

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Message 41 of 52
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hello i tried with your vi still its not coming .....Smiley Sad

look once please...

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Message 42 of 52
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Oh I bet the output gets generated-  Really Really FAST.  You might want a delay in that loop. 


"Should be" isn't "Is" -Jay
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Message 43 of 52
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The example shows ramp by delta and you used ramp by samples.  Either will work as long as you set up the inputs properly.

 

What inputs did you use?  Your VI has 3 controls with the generic names of "Numeric"  "Numeric 2", "Numeric 3" and they are all saved with a default value of 0.  What values did you use?

 

Did you get an error code this time?

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Message 44 of 52
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Change the Ramp function to ramp by delta (use the drop down directly below the VI).

 

Remember that the data sheet of the driver states that Vset should not be set to above 2V.  So you might want to stick with 0V to 2V.


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Message 45 of 52
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hello i used step as 0,1 and stop as 5 v and start as 0v .....i am not getting any value on graph

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Message 46 of 52
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You are still set up to ramp by samples.  Change the ramp function to use ramp by delta.


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Message 47 of 52
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That means you need to change the selector that is underneath the Ramp VI.

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Message 48 of 52
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hello i am trying to get VI grph using laser diode fl500 using USB 6009 ,,and i got one vi file related to my project but i have some promble to get my plot ..which i round with black circle and red circle so please expain me that what device and type are there ???...see below picture thanks..and equipments are 1) muti power supply 2)DDM 3)usb6009 4)laser diode driver  fl500 with 10 ohm resistor ...

vi graph using laser diode fl500.png

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Message 49 of 52
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The image is not worth much. You have not shown the front panel display. What is the exact nature of this problem you mention? Why on earth would you show an image of a snippet instead of attaching the snippet itself?
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Message 50 of 52
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