Current Source

Hello,
I want to build a current source controlled by LabVIEW. I was looking at some information and I found that you can make a voltage controlled current source, which we can control with the 0-10 v analog output of my DAQ card. The problem is that I need to generate currents of about 30 A, so these circuits dont work for my needs.
Do you have any ideas of how to build this current source?
PXI 6229, PXI 6232
LabVIEW 8.2

You can buy a off the shelf power supply which is able to be controlled by an analog voltage for current limit. Set the power supply to the max. allowed voltage and the anlaog control to current limit. Sometimes you need an isolated analog amplifier between the DAQ-card and the power supply to get them work correctly.
Take a look a the specifications fo the power supply to meet all requirements johnsold was talking in his questions.
Waldemar
Using 7.1.1, 8.5.1, 8.6.1, 2009 on XP and RT
Don't forget to give Kudos to good answers and/or questions

Similar Messages

How to control 8 current sources in the same time with labview?

Hi,
I'm a French student who have to create a program which is able to control 8 current sources in the same time.the aim is to plug the currents sources in the input of a laser.
If someone has an idea, it would be very nice to inform me !!!
Thanks in advance.
Nico31dcu

Is it really Tektronik or is it Tektronix. Tektronix is a major test equipment manufacturer. I can't find any reference to that model number on their site, though.
There are several resources for learning instrument control. One good place to start is http://zone.ni.com/devzone/cda/tut/p/id/4357.
Assuming that you have a NI GPIB controller for the pc, you will be using the Instrument I/O Assistant or the VISA commands to send/recieve data from the current sources. Without having access to the programming manual, I can't give specifics on what commands you need to send. Your topic mentions controlling them at the same time. Truly simultaneous control is possible in only a few situations. If you have a couple current sources in the same mainframe, you may be able to send a single command to set them all. It will really depend on the commands that the vendor has implemented. With separate mainframes, you will send commands first to one, and then another, etc. Again, depending on what the vendor has implemented, it may be possible to sequentially program all sources to a ready state and then trigger all simultaneously.

MULTISIM need help with placing current dependent current source?

[IMG]http://i56.tinypic.com/ei7a0n.png[/IMG]
as you can see it is a current dependent current source and has value 2*I(x). i have placed it in a circuit in multisim but i have a feeling i'm doing it wrong:
[IMG]http://i54.tinypic.com/2ppezj5.png[/IMG]
and don't worry about the 25-amp resistor at the right it was the load resistor we had to place.

Hello,
Well from the first circuit you have there, you are looking for the current source to output 2x curret passing between the 10ohm resistor and the 19v source. So you need to connect that line to the current controller (the square thing attached to the current source), basically running a wire from the voltage source to one end of the controller, then running the other end of the controller to the 10ohm resistor (deleting the connection between the resistor and the source so that they only connect through the controler).
Cheers,
Miguel V
National Instruments

Where/how does a current source fit in the IVI class structure

I have not seen any IVI drivers for download for current sources. This is one of the more challenging instruments for me to write general VIs.

According to

Keithley 224 Current Source, 199 DMM Control

Hi everyone,
I can't control some hardwares. Actually, i changed my computer and again install labview, gpib driver etc but i can't control some devices.
Labview connect to Keithley 224 but it can't operate the device.
* Connected to: GPIB0::17::INSTR
-> *IDN?
<- NDCI+0.0000E+0,V+3.0000E+0,W+5.0000E-2«x0D»
I found some topic related my problem but i can't solve that problem.
i solved this problem in past but i don't remember how i can that.
About my system;
* NI Labview 2013 64 bit
*Agilent GPIB 82357A USB to GPIB
*Keithley 224 Programmable Current Source
*Keithley 199 System DMM/Scanner
*Keithley 196 System DMM
*Keithley 2401 Sourcemeter (i can control this device)
*SR530 Lock-in Amplifier Stanford Research System
etc
i attached below some screenshot and my vi's
Attachments:
agilent.JPG ‏84 KB
keithley 224 2.JPG ‏152 KB
keithley 224.JPG ‏120 KB

Ozkur wrote:
Hi everyone,
I can't control some hardwares. Actually, i changed my computer and again install labview, gpib driver etc but i can't control some devices.
Labview connect to Keithley 224 but it can't operate the device.
* Connected to: GPIB0::17::INSTR
-> *IDN?
<- NDCI+0.0000E+0,V+3.0000E+0,W+5.0000E-2«x0D»
I found some topic related my problem but i can't solve that problem.
i solved this problem in past but i don't remember how i can that.
About my system;
* NI Labview 2013 64 bit
*Agilent GPIB 82357A USB to GPIB
*Keithley 224 Programmable Current Source
*Keithley 199 System DMM/Scanner
*Keithley 196 System DMM
*Keithley 2401 Sourcemeter (i can control this device)
*SR530 Lock-in Amplifier Stanford Research System
etc
i attached below some screenshot and my vi's
You'll need LabVIEW 2013 32-bit to work with Agilent 82357A.
You will also need to read http://digital.ni.com/public.nsf/allkb/F7C187DBF09EBE1186256F550065BD32

Controllable current source

Hello ,
I need help in creating a controllable current source using DAQ(PXI-1042). The current range needed is around 0mA to 400mA. Now the current from the DAQ AO pin is very low; around 10mA. How to I get a controllable current of my range? I am trying to use LM317 regulator, but I am not sure about the pin connections. I have attached my circuit diagram here; but that is not working. Can someone please suggest me where am I going wrong? How should i connect the LM317 pins and if there is any other method to get a adjustable and controllable current output? Thanks in advance.
Attachments:
20140206_114946.jpg ‏2843 KB

Hi Shreyas,
did you even try to look up some information from the internet? There are plenty resources on usage of LM317 as this one!
To use the LM317 as current source you need to control the voltage between OUT and ADJ pins. Usually this is done using a resistor. In your case you need to use more than just a simple AO of your DAQ board…
Btw. Do you have any experience in basics of electronics?
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome

Current sourcing problem (AT-AO-10).

This is odd. A month ago, I had no problems sourcing current
(4-20mA). Due to a leak developed in my furnace, I haven't been running
my current source for a while. Today, I get everything back together, and
all of a sudden, my AT-AO-10 will not source current. I pulled it out,
checked the fuse (F2), and it was okay. I tried different channels. I
disconnected my loop, and put in a loop that consists of only a 9V battery
and my multimeter, and I still get nothing.
I've done all I know to do. I can't figure out this one for the life or
me. Has anyone ever seen anything like this? If so, can you tell me what
I might try?
FWIW, I am using a CB-50LP to convert my 5o pin ribbon to separate
connectors.
Thanks,
Harry

Hello;
You didn't mention what version of the NI-DAQ driver you are using over there. Anyway, my suggestion to you is to uninstall the NI-DAQ driver you have installed, remove the board, reboot the machine, download and install the latest NI-DAQ version (6.9.3) from NI web site.
Try the installation with the new driver, and if that is still not working, the best bet is to try the same installation on a different machine to double check if the hardware is not defective.
Regards
Filipe A.
Applications Engineer
National Instruments

NI 4351 current source instability

The internal current source of the 4351 should be 25 µA. Actually, initialization using the measurement and automation tool gives 25, but our application will give us 29. How come? The card is actual "initialize" at 2 places in the code. The first time is for setting some I/O directions and the second for temperature acquisition. I joioned the code. THanks
Attachments:
TempControlInit.vi ‏128 KB
4351Init.vi ‏103 KB

Are you reading from more than one input?
These devieces are very acurate but dog slow. The more channels you scan through, the slower you can read to high precision. Using auto-zero in-between gives you better readings.
Do your inputs look right using MAX?
Ben
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

AC current source

Hi
I need two AC current sources (20 to 200 Hz); what PXI system can I use ? (SMU ?)
thanks for help
ND

Hi,
Thank you for posting your question on National Instruments' forum.
I think the best way to find an answer to your question is to check the ressources on the NI website about PXI SMUs :
Unité de source et mesure de puissance NI PXI-4130 : http://sine.ni.com/nips/cds/view/p/lang/fr/nid/204239
And yes I think that, considering the information you gave, a SMU is certainly the best thing to buy in a PXI format to source a signal.
The best way to get additional information about which product you should buy is to contact your local NI commercial branch.
The sales people there will be the best suited persons to aswer your questions about which product to choose.
Best regards,
Guillaume H.
National Instruments France
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>> NIDays 2011, le mardi 8 février au CNIT de Paris La Défense

Getting Current Source Line Number

I am pulling my already sparse hair out trying to perform the most remedial of tasks: I am trying to trace my code execution to debug it and to log error messages, which is done in C with something like the ubiquitous
'printf ("%s:%d\n", __FILE__, __LINE__);'
I can't for the life of me find anything like __FILE__ and __LINE__ in Java.
How do I determine the current source line number??? I could live without the __FILE__ part if I had to, but the line number is imperative. Where do I get it?
Thanks,
Bill Rebey

"debug" still being a hard work in Java... the oldest Java nightmare :^)))
you may avoid this problem using labels in your code (the problem you must fill your code with debug stuff - if the code is a big one, you will get crazy about that :^) )
or you may adopt a tool able to trace your code execution....
JBuilder do it for you...
Togheter is another good software available out there
(unfortunatelly, both of them are really expensive...)
I don�t remember now about other tools.. (the java has a flag to produce debug output - check in the forum about the debug syntax....)

IFrame current source ..

Hello,
I am using a Iframe to display a URL. The URL opens a HTML page which contains hyperlinks to other side. When click on those hyperlink, the new html page appears.
I questions is how to see or capture what is the current source of the Iframe ?
Ex:
the first html page may be http://www.sap.com
In the html page of sap.com there is a hyperlink "Americas' SAP Users' Group (ASUG) ", when click on this link, it will goto the url :
http://www.sap.com/usa/asug/index.epx
how do I capture the current URL of a IFrame ? (http://www.sap.com/usa/asug/index.epx in this case)
Thanks
UDay

Hi Thirumala
I am opening a IFRAME with a URL. The page displayed in the IFRAME. The page contains hyperlinks to some other page. When I click on the hyperlink, it opens another page in the IFRAME.
Now I want to find out what is the URL of the current page. I tried to get the src of the IFRAME, it is still points to the first URL.
Ex: first launch the Iframe with url http://www.sap.com. The SAP home page appears. the hope contains lots of links. when I click on any one of link, the corresponding page displayed in the same IFRAME. But when I try to capture the IFRAME.src, it is still showing me the http://www.sap.com URL not the current page URL

Independent current source with set of conditional equations

hello,
I'm trying to build this customized block. it has a bunch of fixed value elements (2 resistors and 2 capacitors) and a current source. the current source needs to have a value that's based on a conditional expression expression:
Id = something; for Vgs < something, Vds < something
      something else; for Vgs < something, Vds > something
      something else; for Vgs > something
I have the equations and I have all of the parameters, but I have no idea how to implement the conditional statements for the current source. I'm not even sure where to start. thank you very much for any help.
r.

rob_xx17,
These are Analog Behavioral Model sources, for current, ABM_Current, and also ABM_Voltage for voltage.   They are very useful to set up a series of conditions (relative to other values within the circuit) to generate appropriate controlled current and voltages.
The ABM sources can be found in Master Database -> Sources -> CONTROLLED_CURRENT_SOURCES (or CONTROLLED_VOLTAGE_SOURCES).
Here is an example of using them with a nested if/then conditional.
In this example I1 is depended on the voltage at net(1) - which is simply V1.
So in this example, for I1 you have 3 states (dependent on V1):
a) V1 > 4V, I1 = 1 (Amp)
b) V1 <= 2.5V, I1 = 0 (Amp)
c) V1 greater than 2.5V and 4V or less (inclusive), I1 = 0.1 * V1 (Amp)
Here is a look at the behavior of I1 as V1 varies from 0 - 5V and back from 5 to 0....
To specify a single ended voltage referenced to ground net(0), you just specify V(netname).
To specify a differential voltage, you would state V(net, net2)...
Regards,
Pat Noonan
National Instruments
Attachments:
ABM_Current_Example.ms12 ‏78 KB

10nA current source

Hello all
i would like to generate 10 nA current source through NI PXI card. Is there any PXI card that give me the precision current source upto 10 nA. If 10 nA is not possible then what is the minimum current that can be generated using PXI card.
keyur Makadia
Sr. Application Engineer
Optimized Solutions Pvt. Ltd.

PXI-4130
10nA resolution on 200µA current programming range
Also take a look at the Keithley 238 High Current Source-Measure Unit, 100fA step size at lowest current source range

ABM Current Source - Referencing Nets in an HB/SC

Is there a way to reference nets inside an HB/SC using an ABM Current Source? The ABM Current Source appears to only have the capability of referencing nets on the upper-level circuit and not actually within the HB or SC. This seems like it should be the other way around if it's going to be exclusive referencing some nets and not others.
To reduplicate:
Create an HB or SC with an Input Pin
Put a DC voltage on that pin as an input (ground the DC source)
Inside the HB/SC put a resistor to ground
The IO1 pin will have a net named IO1 for example
Create a grounded ABM Current Source in parallel with a resistor (any value, say 1 Ohm)
For "Value", put V(I01) and then run it - no current
For "Value", put V(1), which references the upper-level circuit input node - that results in current
V(I01) and V(1) have the same potential (they are the same line in essence), but the ABM Current Source doesn't recognize the net inside of the HB/SC

Here's what it sounds like to me:
Under the hood, Multisim is a SPICE simulator
SPICE requires a unique list of net names or else it just won't work
This is the lowest level of abstraction in terms of thinking
about the circuit - essentially it is the flattened view of the world
where all components are on a single page
It might be likened to a computer program written in C++ which
gets compiled down to assembly level, where all the upper-level
variable names have now been replaced by their respective numerical
references
This view of the flattened schematic is essentially the netlist that gets simulated
Now in order to make things a little more user friendly, Multisim has a
bit of UI abstraction -- that is, subcircuits and hierarchal blocks.
These blocks get flattened into the netlist before simulation
In the posted circuit example, net X1.IO1 is replaced by net 1 and net X2.IO1 gets replaced by net 2
This is required at the lowest level of abstraction so that the
list of net names is unique (there is no duplication of a net named IO1)
This is what everyone expects to happen for the circuit to be simulated properly
What is not expected is that you can't reference nets in a
subcircuit or hierarchal block. I didn't entirely follow the last post
about referencing node 33 in a HB as X1.33, because when I tried that
with the posted circuit by making the ABM source value to be V(X1.IO1),
it doesn't work. Referencing a node like X1.IO1 is doing so at the
level of abstraction that the user interface is operating at, but it is
not translated correctly when the circuit is compiled to a netlist. X1
and X2 are flattened to their respective nodes--ie, X1.IO1 -> 1 and
X2.IO1 -> 2, but a reference in the ABM source to X1.IO1 does not
get translated -> 1, so you wind up with a reference to nothing in
the netlist (ie, X1.IO1 is referenced but the X1.IO1 net in the
subcircuit has been flattened/changed to 1, so there is no longer an
X1.IO1 net).
Now lets look at the case of an ABM source inside of a
subcircuit or hierarchal block. This is where I definitely think a few
changes need to be made to Multisim. As has been stated, if we have an
ABM source inside of a subcircuit, we can globally reference any unique
net (ignoring for now previous headscratching over referencing nets
inside subcircuits). So say we have a single circuit, which among
other things contains a single subcircuit, which among other things
contains an ABM source. Even though the ABM source is inside of the
subcircuit, we can still reference anything in the main circuit, which
might be compared to something along the lines of having global scope.
This is a very powerful ability, as we are not limited to referencing
voltages or currents passed into the sub-circuit, but instead can
reference anything we like. So say we set the ABM to reference V(1) --
a voltage in the main circuit. If we now duplicate the use of
subcircuit so that now there are two 'instances' if it on the main
circuit diagram, the ABM source won't change. We don't expect it to.
It's referencing a net that is independent of however many copies you
make of the sub-circuit.
In the same way, we would expect Multisim to reference the net
correctly if we reference a local net, but this doesn't happen.
Multisim knows to translate the nets of the sub-circuit to correspond
with the actual connections of the main circuit so there are no
duplicate nets in the netlist, but this isn't implemented for the ABM
source. If it was, we would expect to be able to reference V(IO1) in
an ABM source. We would expect this to be local scope, not global, and
that any global reference to V(IO1) in an ABM source outside of
the subcircuit would throw an error (but a reference to V(X1.IO1)
should work since we are specifiying the subcircuit and subcircuit
net). Inside of the subcircuit, we would expect that a local ABM
reference to V(IO1) gets translated to global reference of V(X1.IO1),
for whatever instance we happen to be in (X1 in this case), and
subsequently that V(X1.IO1) would be translated to the final connection
for the netlist before simulating, i.e. V(1). If the we were to
duplicate the use of the subcircuit so that there is an X1 and an X2,
then we would expect not to have to change anything, just like you
wouldn't change anything if you were making a global reference. Why?
Because we are referencing the local subcircuit net IO1, which would
get translated respectively to V(X1.IO1) -> V(1) for the ABM source
in X1 and to V(X2.IO2) -> V(2) for the ABM source in instance X2.
The problem currently, is that if we intend to have an ABM source
inside the subcircuit reference the voltage passed in on IO1 of that
subcircuit, we have to reference the global net which IO1 will be
connected to. If we duplicate the subcircuit then the ABM source is
still referencing V(1) instead of say V(2), which is now the net that
IO1 is connected to for the X2 instance of the subcircuit. This is
extremly counter-intuitive, especially for anyone used to programming a
function block with inputs and outputs, where the inputs are operated
on to produce the outputs.
So to boil it down, it seems that Multisim lacks a way to reference
subcircuit nets from within the subcircuit (and on the main schematic)
and have them be translated correctly when the netlist is compiled.
Here are some examples of items that seem like they should be translated correctly but aren't:
Inside of X1, V(IO1) -> V(X1.IO1) -> V(1) in the netlist
Inside of X2 the same V(IO1) -> V(X2.IO1) -> V(2) in the netlist
For the main circuit, V(IO1) = ERROR (net exists but no subcircuit specified) (ie, could be V(1) or V(2), SPICE can't tell)
For the main circuit, V(X1.IO1) is a correct reference and gets translated to V(1) in the netlist
For a specific example, say we model a device that has a fixed
relationship between the input and output terminals, where an ABM
source is used to simulate that relationship. Right now there just
doesn't seem to be a good way to model that, because you can't
reference the local input and output pins inside of the subcircuit. If you only have one instance of the subcircuit, you can change the ABM source to reference the global nets feeding the sub-circuit, but that nullifies the whole point of being able to duplicate the subcircuit and re-use the device model.

ABM Current Source - Current Direction is Opposite

If I use a regular DC Current source of 1A, and an ABM Current source with just 1 for the value (ie, 1A), the direction of current coming out of the ABM source is opposite that of the DC Current source, and in the opposite direction of the arrow on the ABM Current Source icon. This polarity reversal requires a negative sign to fix and is confusing... is there a reason for this or is it just a bug? I didn't find anything noted on this peculiarity under the help files for the ABM source.

My background is in Industrial Electronic Servicing with over 20 years experience analyzing electrical and electronic circuits. I have to disagree with what you are saying. What we know now is called the Electron Current Theory and it is electrons (current) flowing from a negative potential to a postive potential. Way back in history they believed that current flowed from the postive potential to the negative potential. This called Convential Current Theory and is backward from what we recognize today. What you are describing is what I would refer to as "hole theory" where postive charged "holes" travel from the positive potential to the negative potentional. This still would have electrons flowing from negative potential to the positive potential. This is mainly taught to explain the operation of PNP and other P-type components.
With all that said, Multism follows the only accepted theory of Electron Current Flow where electrons flow form negative or ground to postive.or +12V.
I don't know if conventional theory is even being taught in colleges anymore since the Electron Theory is consider the norm. I was taught using the Electron Theory but I did have to learn the other theory and if you have ever used the right-hand-rule for coils then you are using the conventional current theory.
Here's a link that you might find interesting.
http://www.newton.dep.anl.gov/askasci/phy00/phy00628.htm
Kittmaster's Component Database
http://ni.kittmaster.com
Have a Nice Day

Current Source

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