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DAQ Setup for taking measurements from K type thermocouple, Pressure transducer, flow meter and control multiple Thermoelectrics

April 28, 2015, 5:04 pm
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Hi all,

I am a newbie in DAQ and I have only used NI myDAQ before. Due to my inexperience, I am facing troubles selecting the correct modules that fit my needs. I am looking for a DAQ system that would be able to take measurements from multiple thermocouple, pressure transducer and flow meter and also be able to control multiple thermoelectrics. I have requested assitance from the NI staff but I am still not completely sure which modules to get. Can someone tell me what modules I need? I will try to clarify any questions.

 

Thermocouple 

http://www.omega.com/temperature/pdf/tc-npt.pdf

 

Flow meter (Input: 24Vdc   Output: 4-20mA)

http://www.bronkhorstusa.com/en/products/gas_flow_meters_and_controllers/elflow_select/

 

Pressure transducer (Honeywell Model TJE)

- around the same input and output of flow meter

 

Thermoelectrics (Probably this one, not sure yet) 30A, 270W, 15.2V

http://www.customthermoelectric.com/tecs/pdf/12711-5P31-30CZ_spec_sht_20150213.pdf

 

I am not sure if the DAQ can power the thermoelectrics and all the other components.

 

I really need some guidance and help for this. Greatly appreciate it if someone could enlighten me. Thanks a lot.

 

Dennis

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NI LabVIEW 2009 MeasAppChm File (9.0 )

April 29, 2015, 2:34 am
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Hi,

When I installed NI DAQmx 9.3 device driver package, I come across the following files,

1. NI LabVIEW 2009 MeasAppChm File (9.0 )

2. NI LabVIEW 8.5 MeasAppChm File (8.5 )

3. NI LabVIEW 8.6 MeasAppChm File (8.6 )

4. NI Measurement Studio DAQmx for Visual Studio 2005 (9.30 )

 

Are these files necessary to be present in the system ? When I search this file name online, I doubt them to be some malware. What these files are useful for?

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NI USB-6001

April 29, 2015, 3:40 am
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Can I use this low-cost, multifunction DAQ, together with LabVIEW to output an analog signal (sin wave)?

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Necessity of a poisson ratio when using strain gage (wheatstone) measurement

April 30, 2015, 12:44 am
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Hi,

 

I am building this labview interface to eventualy make strain gages measurements on composites samples. I have been testing what I have done so far in half bridge config. and so far so good. I have read about the need of disposing my gages on the material whether in an half or in full bridge ( http://www.ni.com/white-paper/4172/en/#toc1 ). My question :

 

Does Labview need a precise material poisson ratio value(s) when using the DAQmx tools (one of 'strain gage information' asked as input for DAQmx) for getting good accurate values of strain?

 

1) In other words, if I am using 2 gages (half bridge: one in axial direction of the sample, one at 90° of the axial direction on the sample), will Labview DAQmx only use the 'equilibrium purposes' (precision/temperature/offset) of a half/full-wheatstone-bridge-config with only  a relevant poisson r. value?

 

2) If yes: that would mean I need to find the material's poisson ratio for each material type (composite) first. Then, what would be the best way to put my gages (half of full bridge) on the material to find out a 'precise experimental value' of the poisson ratio without having it? (seems like using bending modes are the only way out)

 

(please consider  http://www.ni.com/white-paper/4172/en/#toc1   as a reference)

 

TY,

Daniel

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New signals to cDAQ not working

April 30, 2015, 7:48 pm
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Hi there,

I have a cDAQ-9178 with NI9207 (AI), NI9265 (AO), 2* NI9213 (TC), NI9375 (DIO) installed.  Everything was working fine.

We then added additional signals:

- 1 new AO to one new NI9265

- 1 new DI to existing NI9375

- 4 new TCs to existing NI9213.

Since the additions, the new TC signals work fine, the existing AI, AO, TC signals all work fine.  But I cannot get the new DI and new AO signals to work. Is there a specific step in the set up that needs to be done?  I did not set up the original system so I'm unfamiliar with set up requirements.

 

Cheers.
 

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Digital filtering in PXIe-4330 with hardware timed single point sampling?

May 2, 2015, 12:34 pm
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Hi, a question from a fairly new LabVIEW user:

 

I want to take measurements from a loadcell using the PXIe-4330 module.  It is a real time force-control application, so my main concern is obtaining the latest force reading from inside a control loop.  When setting up DAQmx I see three sample mode options: finite, continuous, or hardware timed single point.  Based on other forum posts, I gather that the single point option is most appropriate for my needs.  Unfortunately, using this approach I see a lot of noise in the readings.

 

I've read that the 4330 module is intelligent about filtering the signals according to the sample rate you use (it oversamples as fast as it can and then applies a digital filter with cutoff determined by the desired sample rate).  Sure enough, when I use DAQ assistant and set the sampling mode to continuous, the signal looks very smooth; it seems the noise is being effectively filtered out.  As soon as I switch to hardware-timed single point mode, the noise returns.  I'm assuming that the digital filtering isn't enabled, or isn't set up the same, in single point mode.

 

Is there a way I can get the 4330's digitial filtering working in the single point sampling mode?  If not, is there an alternative using the continuous sampling mode that would still be practical for a real time control application?

 

Thanks!

Matt Hall

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Samples Acquired

May 4, 2015, 2:14 am
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Hello

 

In the VI attached i am trying to acquire the voltage waveform of an electric bulb.I am using NI-6008 DAQ Card.

Eventhough the samples to read and rate is set as '1k', the number of values written in the measurement file are only 3.


Inputs please.

 

Thanks

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Complete noob - want to measure voltage with manual start and stop

May 4, 2015, 12:59 pm
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Hello

 

As the subject says I am a complete noob when it comes to programming NI.

 

I am looking for someone to point me in the right direction


Setup:

Windows8 Desktop

Visual Studio 2013

NI 6255 PCI DAQ card

NI SCB-68 Connector Block

 

What I want to do:

I want to write a console application to measure voltage on signal ai16

-- I want to be able to manually start and stop the application

-- I want to be able to output the measured voltage to a csv file.

 

Where I am at:

I have compiled and run the "NI-DAQ\Examples\DAQmx ANSI C\Analog In\Measure Voltage" example

It says that I have "collected " samples but I dont know what that means, since I do not see an output file..

 

What I do not understand:

Samples - I do not understand this or even know where to start

File output - how do I get the file to save the data that is collected.

 

 

Thanks in advance

Chad

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digital channel doesn't do clocked sampling

May 4, 2015, 6:44 pm
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Hi, all,

 

I am trying to generate a digital output signal as TTL pulses to control another device. I used matlab daq.session to creat all the possible clock signals matlab suggested for the digital channels to do clock samplng  (sClk/counterChannel or addAnalogInut). Still I cannot get the digitalchannel to work with the clock. Matlab always told me that the channels are not able to perform clocled sampling. Is it possiable that the digital channels on my BNC2110 board or PCI6110 card do not support clocked sampleing? Is there anyway to get around it?

I am able to use ni-max to toggle the digital channels to turn on the devide that I want to control. So it seems to me that the hardware are okay.   

 

the system is :

matlab r2013b

BNC2110 board

PCI 6110 card

whidndows 7

12G RAM

 

Many thanks,

 

mc

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9207 incorrect read out - possible wiring problem

May 5, 2015, 4:11 am
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Connecting both voltage and current  sensors to my NI 9207 result in faulty readouts in Distributed system manager.

 

Situation:

NI cRIO9075 with module NI9207 powered by a NI PS16.

 

To this I have connected a floating voltage channel, a grounded voltage channel and a self powered current channel. (see schematic png)

 

For the grounded voltage channel I measure the same values in Distributed system manager as with my Fluke 83 Multimeter.

For the floating channel I measure a correct  value as well.

But for the self powered current channel I see a slightly lower value for NI compared to my actual current output.

(i.e. output = 18mA, NI=15mA  or   output = 0.12mA NI = 0.10 mA etc.)

 

I suspect there is a problem with the grounding or reference point of the current measuring module. Since I had similar problems with my floating

voltage channel before I grounded it correctly using the 1M resistor.

 

Is this the correct way to connect the module? Or is something amiss?

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Is there a way to watchdog an 1163R

May 5, 2015, 8:55 am
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I would like to insure the 1163R output goes low should a system crash take place.  I recently started using a USB 6525 for some systems so I could use the chassis slot for other items. Because of a timing issue I discovered the watchdog capability of the USB 6525 and developed my application to watch the device and go to a low state as a fail safe.  This watchdog would be useful on the systems using the 1163R but it appears this is not supported by the device. Since the device is never in the high state for over 500 milliseconds at a time the risk is low but still possible to have a system crash at just the wrong time.

 

Currently I am using a simulated 1163R on my development and getting the device not supported error. After checking documentation I do not see a watchdog timer mentioned which supports the message I get on the simulated device.  Short of the watchdog timer are there methods using the 1163R to insure the hardware goes to a safe state in case of computer failure?

 

Thanks,

Randall

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Which devices and software excatly need I?

May 5, 2015, 7:24 pm
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Hi,

 

I lost in the the system configuration, i dont know which devices, and accessories need I.

 

I have to do a pid control., I need NI 9237 daq to receive the signal from the load celland NI usb 6216 daq to control a pressure relief by the received signal by 9137. I need also a full labview development system. thats ok.

But is there anything? I dont understand why need i chassis and controller?

 

With just Ni 2937, 6216 and labview, can i do this regulation?

 

 

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Acquired Samples

May 5, 2015, 11:33 pm
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Hello

 

In the VI attached , I want to write the current data acquired from a lamp into a measurement file. Currently when I run the code only 3 values are written eventhough the samples to read and rate is set as '1k'.

My aim is to keep acquiring and writing the current data into the file untill the elapsed time runs out.

 

Thanks

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Getting -201300 on DAQmx_Read_ChannelsToRead

May 6, 2015, 6:43 am
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MAX version 14.5.0f0

DAQmx version 14.2

 

Hi, I'm stating to look at the logging feature.

 

I created a Task in MAX with 4 channels on a simulated USB-6255 device.

Set the Logging mode to Log and Read

Then in my 100% fully functional C++ code to run the Task.

It uses the DAQmx_Read_ChannelsToRead method.

Then I get the error -201300 DAQmxErrorAttributeNotSupportedWhenLogging

Why?

 

-cpede

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Using PCIe6320 with SPI communication

May 6, 2015, 7:31 am
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Hello,

 

Quick question. I wonder if it is possible to use a PCIe 6320 in order to use a SPI communication and the SPI digital waveform reference library ?

 

Thank you for your answers,

 

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Distorted Output with NI 9263

May 6, 2015, 2:36 pm
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I am currently working on a project but I have run into a road block.

 

I cannot get my DAQ to output a clean signal I and I am sure what I am doing wrong. I am using a NI 9263 DAQ with a NI cDAQ 9172 chassis. I made a very simple vi to test the hardware but the results are not very good, and even when using a 96kS/s sampling rate to generate a 1kHz signal produces rather poor results.

 

I have included the vi I used to test the hardware and pictures of the output. Any help would be greatly appreciated.

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NI9205 SIngle ended input with burden resistor

May 7, 2015, 3:24 am
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Hi,  

I am using a NI9205 module with spring terminals configured for single ended inputs. The inputs are measurement signals from current transducers and so I need to connect a burden resistor between each input and ground, as per the diagram attached. Can anyone recommend a neat way of installing the burden resistors for this application?

 

Regards,

Mark

 

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How do I read voltage on multiple channels using the 6255\SCB-68

May 7, 2015, 10:19 am
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Hi All

 

I was able to get the following code to compile, run and view the voltage data as expected. when reading the voltage (RSE) on Dev0/ai65

...National Instruments\NI-DAQ\Examples\DAQmx ANSI C\Analog In\Measure Voltage\Cont Acq-Int Clk\ContAcq-IntClk.c

 

* I think that I am using RSE but I have no clue since I do not see an argument to specify

 

 

I am trying to read two different data points:

1. View the voltage (RSE) on Dev0/ai65

2. View the voltage difference (Differential) between Dev0/ai17 and Dev0/ai25

 

Can someone point me to an example (or web link) where two different data points are being read.

 

*edit - I am trying to complete this task using C++

 

 

 

Thanks

Chad

 

 

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How can I connect them?

May 7, 2015, 10:33 am
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Hi,

 

This is the system and I dont know excatly, which cables, or other devices need I, how can i connect the DAQ with the perrure relief and the amplifier. I am new in this field. I attached the amplifier and the pressure relief data sheet. THank you!

 

qqqq.jpg

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NI 4472 coupling on Labview

May 8, 2015, 6:52 am
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Hi everybody,


I have a PCI 4472 acquisition board, Labview 2010 and DAQmx 9.3. The board accepts both AC and DC coupling and I can successfully set it in the Test panel on NI MAX, but I can't find a function to set the channels coupling on Labview.


Thanks for the help


Tommaso

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