Daq problems voltage ramping

Im using SCB-68 with a PCI-6221 DAQ Card. Im capturing data from an analog input 2 and its just two AA batteries 3vDC. When i let MAX run and open a test pannel for input 2 after about 15 mins the voltage graph jumps to 10.6 volts and remains there. I have no other programs running, and its just the test pannel window. I calibrated and retested and it does the same thing. Whats going on, so confused

Hi!
Seems that there is something wrong with your terminal configuration. I would suggest to use RSE or NSRE (Task configuration) and also use bias-resistors from the signal lines to the ground. You will find more information about this within the MAX help!
BR, Christian

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Voltage ramp

The attached voltage ramp works. The supVI that actually does the ramp is timed correctly and will complete on time. However, the calling VI seems to take some time to pass and receive variables and the total time gets off. The ramp is for cDAQ-9172 using module NI 9263. I setup an array of 9 elements that can be scaled upward if needed. You would simply duplicate the last case, add a repeat control to the global vi and change the references to the new repeat control (note the repeat controls are hidden in the global VI). To make the program end you simply put the same sequence number in the last sequence. If you had three sequences then on the third sequence you would select sequence 3. When sequence 3 completes the program ends. Use the repeat to step back over a previous sequence numerous times before moving to the next sequence. This all works ok just runs a bit long as stated above. Glad to share this VI and hope someone could guide me on how to correct the timing issue. If someone has a completely new way of doing this I'm open to suggestions.
Attachments:
Ramp Voltage.zip ‏182 KB

Hi bassinbc,
The time probably gets off because you are creating your DAQ task and clearing the task each time the subVI is called. There is overhead to doing this. I also notice that everything is being timed with software timing. There's no guarantee that your timing will be accurate when performing software timing. You may want to consider calling the create and clear task functions in a seperate part of the program rather than the subVI that is repeatedly called. I hope this helps!
Mike Lyons
National Instruments
http://www.ni.com/devzone

Voltage ramping VI - looping error?

I am using a previous VI for my Xantrex PSU that sets current or voltage of the PSU. I have added a loop to it that will allow me to ramp up the voltage given set user values (timing, scale, etc.) Those parts work. However, in my VI the loop does not set the voltage of the PSU, but sets it to the value only AFTER the loop has finished.
I know my counting is correct, because it displays proper count up rates.
Any help with my VI would be much appreciated!
Thank you,
Steve
Attachments:
Voltage Ramp.vi ‏46 KB

The reason is because you are setting your voltage (config voltage vi) only once and outside the loop. Move this VI inside the loop so that you reset the value repeatedly. Click on "highlight execution" (the yellow bulb) while viewing your block diagram and run the program so that you can see the program flow, and you will see what the problem is.Message Edited by Sudhir Gopinath on 06-14-2007 01:27 PM
S G
Certified LabVIEW Architect, Certified TestStand Developer, Certified Professional Instructor

Need help with daq problem

Hi,
I need to generate a clock with a period of 20 micro seconds, duty cycle of
approx 20% and a data line as well as an address line all linked to the clock
pulse.
I have tried many different solutions, all using the Daq PCI-1200 but nothing
seems to work correctly. Usually the system bombs and I have to do a manual
reset to over come the problem.
Any suggestions?
Ken

Hallo, Ken,
Du meintest am 20.02.00 zum Thema Need help with daq problem:
> I need to generate a clock with a period of 20 micro seconds, duty
> cycle of approx 20% and a data line as well as an address line all
> linked to the clock pulse.
You'll need an external clock, expecially under Windows.
Windows ticks with appr. 18 Hz, and the CPU tick isn't always available
when Windows tasks multi.
Viele Gruesse!
Helmut

When I send a 5v from the DAQ, the voltmeter shows 5V, but when i connect a "normally open valve" from parker to the DAQ, the voltage automatically decreases to .14 V. It seems like it is being grounded. Why is this happening?

We are sending 5v to the DAQ using a voltage generator. We hook this up to a voltmeter and we see 5V. When we connect the voltage generator to a "normally open valve" from parker, the voltmeter shows .14V. It seems that when we connect both wires from the valve to the voltage generator, the wires are acting as a ground. We wish to control the voltage that flows to the valve through Labview. We checked the wires of the valve and they are working fine becuase if we send a constant 5V from the DAQ and grounded it, the voltmeter shows 5V. Does anyone know why the wires are acting as a ground and dropping the voltage to .14V?

nsatpute wrote:
Our DAQ is NI USB 6259. The valve only requires a max of 5V and our DAQ does provide up to 5V. However, after connecting the valve to the DAQ, the voltage drops to almost 0. We are assuming that the wires somehow act as a ground, but we are not sure if this is the case.
The issue here is not how much voltage the valve wants, it is the current the valve needs. The 6259 can only put out 5mA through an analog output. Your valve very likely needs a lot more than that. So you need to add in an amplifier circuit that can supply more current to operate your valve.

Pressure Profile System - (ConTacts C500) - DAQ problem

I am working with a new system that my team has had for a while - a C500 ConTacts system from PPS. First off, I am hooking the system up to a SC-2043 SG board. The ConTacts system has a +12, ground, and out wire terminal. I hooked the +12 to the + Ex channel, the ground is grounded, and then the out channel to the +Ch on the SC board. When I run my program, or the test panels, all I get is a value that is what my voltage is set at.
Has anyone used this type of system? It seems to be that I have a simple connection problem, but can't solve it. I've used tons of strain gauges with my DAQ board and Labview, but can't get this thing to work. Any help? I hook it up in the same manner, but nothing. I've tried a lot of stuff to no avail, so any help would be awesome.
Secondly, the ConTacts system has a non-linear pressure profile. I want to incorporate the Excel calibration file that came with the system so that it will display the actual force. Best way to do this? Can't seem to find any good examples. Basically it would be a look up table where it records "x", then goes to the excel file to find the right curve, and then plot out "y". Is the best way to best fit the curve in excel and then just use Labview to plug in the equation? any help is also appreciated here...

Hello,
What Data Acquistion board are you using with the SC-2043 board? Is your strain gauge full, half, or quarter? One thing I noticed is there is no connection to CH-, so if you wire that to ground do you see any changes? By -1, do you mean it is railing at -1V?
Kyle A.
National Instruments
High Speed Digital I/O Product Support Engineer - R&D

DAQ Problem

Hallo everyone
I have a problem, I try to provide a task in order to mesure the Voltage with the help of the DAQ-Card.
normally under the list " Supported one physical channels" should indicate the available channel of all existing DAQ-Card.
however it is not the case with me , it is written : " No Support devices found ".
Although i installed the drivers 2 times and the Test Panel of DMM ( PXI-4065) and of DC power supply (PXI-4110)are working.
Would u plz tell me what should i do , and where is the problem
P.S : it is my second week that i am working with LV
Attachments:
Pic1.JPG ‏132 KB

PXI-4065 and PXI-4110 are not DAQ card
use "help>>Find examples" and select your hardware (see PNG)
Message Edité par A. Dek... le 02-12-2008 09:38 AM
Attachments:
FindExamples.png ‏52 KB

Conditional Voltage Ramp

My goal is to ramp a voltage until a specific condition is met, and once it is met ramp the voltage downward at a different rate, what should my approach be?
I know how to create a ramp waveform with an array, but I need this to go on indefinitely until the condition is met so I don't see how an array could work with this.
Thanks a lot for the help

phrygian wrote:
What does the 10.00 attached to the DAQ write function do?
It "specifies the amount of time in seconds to wait for the VI to write all samples" (from the detailed help).
And also what is the difference between using a for loop with a conditional terminal and a while loop?
Either is fine. I chose to use a For Loop to make it more clear that the loop is iterating over the elements in the array.
In the example you just posted there is no start task VI, why is that? If I added in voltage and current inputs would I need to have start task VI's for them?
There's an "auto start" terminal on the DAQmx Write vi that takes care if it for you (default value is TRUE). The same will work if you add voltage and current tasks.
Jim
You're entirely bonkers. But I'll tell you a secret. All the best people are. ~ Alice

DAQ problem reading data

I just instaled the PCI board together with the CA-1000
Connector Accessory Encloser. The test panel works, so I know that the device is installed. But when I connect a signal to the port on the CA-1000, I don't see
the signal appearing on the test panel display. I just
see a signal that is constant,
with a little variation.
By the way, I also have the PCI-GPIB card installed.
Thanks! Matt

Chuck;
The problem there is most likely due to a bad connection somewhere.
My suggestion to you is to cross check the connection you made with the Users Manual of the CA-1000 and DAQ board to confirm you done everything accordinly.
If that is not the case, the CA-1000 is probably damaged.
Regards
Filipe A.
Applications Engineer
National Instruments

DAQ problem on Version 8.5 doesn't work, it freezes up!!

Can anyone help me please?
I need to get daq assistant and a signal generator from the block diagram for a new VI, but found everytime I put it in place and try building the VI the whole labview development suit freeze up and I had to shutdown labview by task manager.
I can bring the daq assistant and the signal generator icons from the measurement I/O from the function palate. But, when the setup window launches it just freeze up and halts, can't do anything more. Did anyone else had the same problem?
I have labview 8.5 and my operating system is Win 7 pro with XP virtual mode instaled. I have already done some works on this version 8.5, but DAQ not seems to work on it, installed it not too long ago. can anyone help please? Thanks in advance.

LabVIEW 8.5 supports up to DAQmx version 9.3. I would definitely reccomend installing this version if you can.
There's a great little KB here I can reccomend:
http://digital.ni.com/public.nsf/allkb/DC7EBB1316F3406A86257894007BD75C?OpenDocument
Nick C.
Cardiff University

DAQ Problem when migrating to LV8.0

Hallo,
I have a piece of code which was originally written with LV7.1.1. It deals
with a NI6289PCI card. This code has been verified. Now I've migrated from
LV7.1.1 to LV8.0 and trying to load this code returns an error. A VI called
"Get Terminal name with device prefix.vi" was not found. As I can remember
these were from the TraditionalDAQ palette.
This vi takes and returns a task reference and it takes a string which is
"ao/StartTrigger" and "ao/SampleClock". Finally it returns a DAQmx
reference of something that is wired to the source inputs of DAQmxTiming
and DAQmxTrigger.
How can I get the functionality of this missing VI with modern DAQmx means.
I know that it has to do with synchronizing clocks and waiting for a
trigger.
Thanks for your help.
Regards
Oliver Friedrich
My email has no x!

When you installed 8.0 did you install new drivers as well. If you did not i would install the traditional daq drivers and make sure that they can be used for 8.0. This goes for DAQmx as well. make sure when you open LV8.0 that these functions are available in the measurement I/O pallette if they are not then they need to be installed then your problem should go away.
Joe.
"NOTHING IS EVER EASY"

DAQ problem in this specific VI

The purpose of this program is to drive a piston to cause a pulsitile flow in a pressure loop. The waveform graph is there to collect flow and pressure data from 5 sources. The DAQ assist will not collect data in the program (Working Strain Gage) but will collect it individually if the while loop containing it is copy-pasted into a new VI. I have tried everything and have no clue what it could be. I attached the VI and the subVIs included in it. Thanks!
Attachments:
Working Strain Gauge Control Rev 8 BMJ.vi ‏137 KB
Offset_Gain_BMJ rev 1.vi ‏81 KB

Well, I am not really sure what the logic is doing. The code is very confused. Stop using sequence structures. Use data dependencies to establish order of execution. Also stop using the express VIs and the dynamic datatypes.
One problem is that in the event structure, when some button is pressed, a VI is called that in order for it to complete you have to click som buttons on its front panel. The problem is that this VI's front panel isn't open so you can click on anything. Beyong that I really can't tell what is going on.
In your top-level VI you already have an event structure -- so use it as the basic for your application. You need to spend some time learning about how LV and, specifically, dataflow works.
Here are some links (courtesy of Hoovah):
3 Hour Introduction http://www.ni.com/white-paper/5243/en/
6 Hour Introduction http://www.ni.com/white-paper/5241/en/
LabVEW Basics http://www.ni.com/gettingstarted/labviewbasics/
Self Paced training for students http://www.ni.com/academic/students/learn/
Self Paced training beginner to advanced, SSP Required http://sine.ni.com/myni/self-paced-training/app/main.xhtml
LabVIEW Wiki on Training http://labviewwiki.org/LabVIEW_tutorial#External_Links
Mike...
Certified Professional Instructor
Certified LabVIEW Architect
LabVIEW Champion
"... after all, He's not a tame lion..."
Be thinking ahead and mark your dance card for NI Week 2015 now: TS 6139 - Object Oriented First Steps

DAQ problems..... error 50103

am have a problem with my vi.I have a main vi that can select different vi's through a subpanel, also on the main vi is indicator for a power supply and one for a load cell if these go under the rquired level or above a weight they stop.
The problem is that when I select one of the operations calibrate and read height ( see attached library ) the DAC has a error which I dont know how to fix. the error is 50103 which occured at DAQmx Read (Analog 1d wfm Nchan Nsamp).vi or at DAQmx Start task.vi which is in the DAC assistant front panel when you open it. It is in the library attached the main.vi is viewer open that and run it and ye will see
ye might have to put a constant for the load cell and battery to stop them for stopping it
I am using DAQ PCI-6040e
Attachments:
menu.llb ‏1981 KB

Your DAQ Assistant task is continuous. Yet, you only read data once. So it would appear that a finite task would be better. I'm pretty sure that you get this error the second time you run this sub-vi because the task, started the first time you ran it, is still running. That's why you get the resource reserved error.

Mac G4 OSX DAQ problems

I am attempting to run LabVIEW 7.0 on a mac G4 with OSX (10.3). I downloaded the newest NI-DAQ driver DAQmx 1.4 and installed it. I have a PCI-6025E board installed in the machine.
NI-DAQmx Base Config recognizes the PCI board and allows me to configure it.
If I attempt to run in the Classic environment,the NI-DAQ Configuration Utility does not recognize the board. I cannot therefore configure and use channels.
Thomas D. Schaefer
Wells Manufacturing Corp

Why are you trying to run under the classic environment? LabVIEW 7 is an OS X app, and I believe the same is true for the new DAQmx drivers. It does not surprise me that you would have problems communicating with hardware between OS X and the classic environment as hardware is abstracted from the "TrueBlueEnvironment". You would need a classic version of the DAQmx drivers. Do you have any trouble accessing your hardware from the native environment?
Chris

Simple DAQ problem

Dear Sirs/Madams,
I'm trying to take N voltage readings from a single channel on a BNC aquisition board/PCI-6251 (multiple channels will be later) - and I get some kind of error message which I don't understand. The code and error message are attached.
Thank you for your help.
Attachments:
daq28032007.vi ‏26 KB
error message.PNG ‏17 KB

Hello Raff,
The problem is that you have a 'Clear Task' function in the for loop. This means that the second time the loop iterates, the Task reference you have specified as a tunnel on the left hand side is no longer valid.
Just move this 'Clear Task' function to outside the for loop, and this should solve the problem.
Putting all the code in the for loop will make it work, but will give extra unnecessary overhead.
I hope this helps
Regards
Hannah
NIUK & Ireland

Daq problems voltage ramping

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