How to initialise DAQ cards prior to AI_Vread?

I have a problem when i use the AI_Vread function. It appears to me that the i need to initialise my daq card before it can start to pick up the readings from my voltage source. Please advise me!!!

Hello;
You can refer to one of the shipping NI-DAQ examples code. For your case, I believe you can look at the one named "AIOnePoint.c"; which can be found at C:\Program Files\National Instruments\NI-DAQ\Examples\VisualC\AI.
Hope this helps.
Filipe

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How to monitor DAQ card outputs during TestStand operation?

I am trying to debug a rare failure mode on a test station that runs on TestStand. TestStand controls measurement equipment through a PCI-GPIB controller and a DUT and DUT switch box through two NI-DAQmx devices; PCI-6509, and PCI-6534. I believe that root cause of the failure is due to the software not putting the DUT into the correct state for the test. In order to check this I need to monitor the changes on the GPIB and DAQ cards. I was able to use NI Spy to monitor the commands on the GPIB bus but I have not been able to monitor the state of DAQ cards. Is there a tool that will allow me to pause TestStand during its operation and look at what logic states the PCI-6509 and PCI-6534 outputs are in? Or at least monitor the I/O of the PCI-6509 and PCI-6534 cards similar to what NI SPY offers for the GPIB cards?
Regards,
David

I am not aware of a tool similar to NI SPY for I/O cards.
However you can introduce a break point at the point of interest in a test sequence(step).TestStand will stop execution at that point.
You can then manually verify the I/O status using a DMM .
Hope this helps.

How a DAQ card acquire resistance/position/frequency?

I don't understand a thing...
how a DAQ card can acquire (directly)
a position, a frequency and so on.
I had a look at examples folder (ANSI C)
and found examples to read
frequency, position.
An ADC can acquire only voltage.
How with a DAQ card I can acquire
linear position, resistance and so on?
Thanks in advance.

Yes, normal DAQ ADC read voltages, However most DAQ-Cards provide some supply/exitation voltage/current you can use together with an sensor that deliver a voltage or a current, with thanks to Ohms law can be transposed to a voltage
linear position -> potentiometer -> voltage
frequency is measured with timers
Greetings from Germany
Henrik
LV since v3.1
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How do I use two DAQ cards in one Labview code? Current I'm getting error " error 200558 occurred at DAQmx Create Channel.vi. One task cann't contain multiple independent devices". Can someone help me?

The two DAQ cards are NI PCI-6070E & NI PCI-6052E. The Labview I'm using is labview 7 Express and the Window system is Window XP. I'm using NI SCXI-1000 chasis and SCXI-1102 & 1102B two modules plus a feedthrough SCXI-1180. 1102 is connected through SCXI-1349 cable to DAQ card 6052E while 1102B is connected through SCXI-1349 cable to DAQ card 6070E. SCXI-1180 is connected to 6070E through SCXI-1349 adaptor on the back of 1102B.

Sarah, thank you for replying my question. It seems that I'm making progress everyday (smile). I'm able to run the test using both daq cards in my code now. But as I'm moving forward, I'm getting new questions too. How do I use one STOP button to control both tasks and how can I save data into one single file?
I attached my code here hoping you can get the specifics on my application by looking at the code. Thanks very much!
Thanks.
Attachments:
DAQmx_Task_Example_plus_voltage_2.vi ‏416 KB

How can I create software start and stop trigger in LabView using 6023E series DAQ card? I don't want to use the external trigger.

I am using 6023E DAQ card to collect the signals, such as AE, Force, Torque from the machine. I want to collect only some part of signal for example between start triger and stop trigger. I'd like to know how I can creat those triggers in LabView from one of the channels that I am acquiring at the same time. I found one or two library file that is only for start trigger. I know that this is availabe in some of DIAdem functions. Please let me know if you have done some example for this requirement.

If you are wanting to create a software trigger based on an analog input voltage in LabVIEW, there are several options. One suggestion would be to compare the voltage values from one input channel to a number within a loop. If the input voltage crosses that threshold (is greater than the number), have a case statement that will acquire data from the other channels. This would simulate a software start trigger in LabVIEW.

How to generate a pulse waveform 90 deg phas shifted with respect to a pulse generated using a counter in PXI 6070E daq card ?

Hi
I ma using 6070E daq. I am generating a infinite pulse train using one of the counters. I want to generate another pulse train which should 90 degress phase shifted with respect to the previsously generated pulse. How to implement this using the counters in the DAQ card.

Hi Gopal,
1) yes the frequency generator is programmable. You have 2 timbebases (10MHz and 100kHz) and you can divide down by any integer between 1-16. Those are the only frequencies you can use.
2) The way counters work is that you can apply a gate signal to the counter which will cutoff the output. Therefore, you can have a second counter generating a pulse train of an equivalent frequency to the frequency generator (fout) but you don't want it to start immediately. You want it to start only after a short delay (equivalent to a 90d phase). Therefore, you need to "gate" or prevent the output on this counter for that small delay period of time. The way you can do this is by using a second counter to create a delayed pulse. You would
connect the output of that counter to the gate of your pulse train function. That way, during the delay period of the pulse, you won't be outputing your pulse train yet. When the pulse (high-time) of your pulse reaches the gate, then your pulse train will start generating its pulse train (which is consequently delayed by the amount of delay used in the single delayed pulse counter). Since you don't want your pulse to go back low, you will have to turn off or clear your pulse counter while it is high. That way the signal on the gate will remain high forever.
Your better solution is to use a PCI-660x card to perform this action. You will have more counters which will give you a greater range of frequencies to choose from and you will have more accurate timing of the signals.
Anyway, hope that clears things up. Have a good day.
Ron

How can I make a timer that will record elapsed time up to 15 hours with a PCI-6503E DAQ card?

I'm a beginner LabVIEW programmer, but need to take measurements of elapsed time from the start of data acquisition for up to 15 hours. I'm using a PCI-6503E card. Looking at examples on the web and LabVIEW, itself, I was only able to find a way to take time measurements with a DAQ card up to 167 s, unless two counters were tied together, but there are no instructions on how to do that. Could someone help me? Thanks.

I suggest you to look in the Resouce Library: inside it there is plenty of useful examples.
I found this VI with two cascaded timers in the Measurement hardware > Counter/Timer > Event/Time Measurement cathegory:
http://zone.ni.com/devzone/devzoneweb.nsf/opendoc?openagent&5293158F4EC950C4862568C1005F6CD9&cat=C7029C9ACBD3DF7386256786000F8EE6
Hope this helps.
Roberto
Proud to use LW/CVI from 3.1 on.
My contributions to the Developer Zone Community
If I have helped you, why not giving me a kudos?

How does the PCI-6229 DAQ-card communicate with CB-68LP connector block?

Hello!
I want to do a very simple task which is to just turn on/off a LED. I am using LabVIEW 7.1 and I have a DAQ-card PCI-6229. The DAQ-card is then wired to a connector block CB-68LP.
Now my problem is to figure out how the connector block communicates with the DAQ-card?
In the file I attached there is a picture of connector block and the device pinouts from the DAQ-card. But how do I know which of pinouts triggers some connector on the connectorblock?
Which are digital outputs on the DAQ-card?
Where can I read about this?
Attachments:
daqANDconnectorblock.bmp ‏2437 KB

Hello asc01001:
The digital pins of the PCI-6229 are labelled as Px.y, where x is the port name while y is the channel name. For example, pin52 of the NI 6229 is P0.0; which is also port 0, channel 0 of the digital I/O of the DAQ card.
While "D GND", which are located at pin53, pin18, pin50, etc. are the negative terminal of all digital I/O of the DAQ cards.
Please advice if this helps.

How to avoid dependance between output digital port with a PCI 1200 daq card?

Hello,
I don't manage to fix the state of a line on one port (PA0 for ex) without change the state of another line of another digital port (PB0 for ex)
I use a PCI 1200 Daq card with Labview 5.0.1 (under Windows 98)
How to configure a robust state (high logic level) on a line of a port??
Does anybody have an idea on this problem?
Thanks a lot in advance and happy new year to the community
JF LAVEZARD

jflab a écrit:
Hello,
I don't manage to fix the state of a line on one port (PA0 for ex) without change the state of another line of another digital port (PB0 for ex)
I use a PCI 1200 Daq card with Labview 5.0.1 (under Windows 98)
How to configure a robust state (high logic level) on a line of a port??
Does anybody have an idea on this problem?
Thanks a lot in advance and happy new year to the community
JF LAVEZARD
Hello,
I've found the problem
The PCI1200 has a chip 8255 for Digital I/O
If I use the bad VI, it reconfigures the port and all the lines go in a low logic state
so I'd to write only on the port or the line without reconfigure the port
So the good VI in the palett is: Port Write and not Digital Port write!
See attached file..
Thanks
Best Regards
Attachments:
port_dio.jpg ‏771 KB

How to switch multiple relays using PCI 6601 DAQ card

What is the specification of the digital output value given from the PCI 6601 DAQ card?How to develop LAB VIEW code to switch a relay?Can anybody please explain?

Hi hasi,
did you read the manual and the specs of the PCI6601? It says: "5V TTL/CMOS compatible"...
You shouldn't expect to much current from a simple DO pin - probably it's not enough to drive your relay!
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome

How to arm channel 1 of a PCI 6133 DAQ card using labview?

Hi,
I am new to the Labview and I need some help. I have a PCI 6133 multifunction DAQ card and I'm using Labview 8.2 to capture five channels waveform data. I setup channel ai0 to be the trigger channel and I need to capture data from ai0, ai1, ai2, ai3, and ai4 when ai0 is trigger.
Question:
1) I am using DAQ assistant to configure my channels. How can I arm the channel ai0? I have an "execute button" and it should arm the scope when I click it.
2) Is there trigger ready signal, so I can save all the channels data when channel ai0 is trigger?
Can anyone provide some help?
Thanks

Hello wirte spreedsheet,
Thanks for posting to Discussion Forum. It looks like you are using the
PCI-6133 to acquire analog data from ai0:ai4. You want to use ai0 as
the trigger for the other channels.
Does your application need to be retriggerable?
Are you doing continuous acquisition?
Are you doing Analog start trigger or reference trigger?
Take a look the following shipping examples, found in LabVIEW click
Help>>Find Examples. On the browse tab, Hardware Input and
Output>>DAQmx>>Analog Measurements>>Voltage:
Cont Acq&Graph Voltage - Analog SW Trigger.vi
>> This example demonstrates how to perform an analog software
triggered acquisition. The example allows the user to specify the
triggering condition and the number of pre-trigger samples to acquire.
Cont Acq&Graph Voltage - Int Clk - Analog Start.vi
>> This example demonstrates how to continuously acquire data
(Waveform) using the DAQ device's internal clock and an analog slope
start trigger.
Take a look at these applications and let me know if you have any questions or comments.
Have a good day.
Regards,
Sandra T.
Applications Engineer | National Instruments

How to use PXI 6071E daq card to complete multichannels scan with high sampling speed

I used pxi 6071E daq card to acquire 115v 400hz AC signals.when I use mutichannel scan function,I find that the voltage of waveforms have much more error.The voltage error is about 0~15v.please you can tell me why this happened?how to solve it.
Attachments:
多通道监测4.vi ‏199 KB

Sunny;
As you are scanning multiple channels and the signal range is high, you can try to set the interchannel delay a little higher. The interchannel delay is the time which the multiplexer will take to switch to the next channel. If that time is to short, the instrumentation amplifier can have problems to settle, and then an error at the reading will happen.
You can change the Interchannel delay at the AI Config.vi.
Hope this helps.
Filipe

How to run VI without the DAQ card connected to the labtop

This may be a silly question but I want to have the answer and couldn't find the answer for spending time in searching in the web.
I want to run the VI that controls the intruments in my labtop. The VI was run in a destop that has a DAQ card in the PC (a PCI card). I know it is possible to run it without errors (without a DAQ card) in my labtop . Anyone knows how to do it? I used labview 7.1. Thanks,
Jun

If you are using DAQmx and if the DAQ card is supported, you can add a simulated device in MAX.

How to control two 6011e daq card to acquire eight signals simultaneously.

I use two 6011e daq card to acquire eight signals simultaneously .I use labview function to realize it,but the data graph show that the signals aren't acquired simultaneously,why?how to do it?

Hello;
You need to use the RTSI bus to route one board's clock signal to be the second board's clock signal. By doing that, you will have the same signal clock timing both boards, which will make the synchronization hardware timed.
You will need to have a RTSI cable connecting both boards together also.
The best way to go about this is to open the Labview examples that show how to synchronize multiple devices. You can apply the same idea to your board.
The examples can be found at Search Examples->I/O Interfaces->Data Acquisition->Multiple Device DAQ Examples.
Hope this helps.
Filipe

How SCXI modules are multiplexed into one Channel of the DAQ card?

Hi all,
I am Sirisha from Hyderabad.
I am a new to NI hardware.
take the below mentioned senario.
Suppose i am using SCXI-1000 chassis with SCXI-1520 and 3 SCXI-1102 modules and PCI-6070E DAQ card.
now i know that if i connect the DAQ card to the SCXI chassis through sh-6868 cable and 1349 adapter, all channels of SCXI modules are multiplxed into the 0th channel of DAQ card.
Here i want the detailed explanation of theory of multiplexion on how all the scxi channels go to 0th channel of DAQ card
Thanks in advance
regards
Preetam

Sirisha,
Thank you for contacting National Instruments.
Here is a KnowledgeBase article entitled "How Are SCXI Channels Multiplexed While Having Other Inputs On The DAQ Card?"
There is a little more specific information about multiplexed mode here.
Michael P
National Instruments

How to initialise DAQ cards prior to AI_Vread?

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