No proper signal with NI-4351 DAQ-card

Hello,
I am trying to use a NI-4351 for temperature measurement (together with TX-68T connector block). However, I don't get a proper signal in our laboratory. Using the MaX and looking at the test panel: there is sometimes the right voltage but most of the time the signal is noisy or even more than that: it is jumping to the maximum and minimum of the voltage range (for every voltage range).
In an another building with another supply circuit the signal is okay. So we suppose an EMC problem: Together with the Elec. department we have disconnected all "critical" consumers- no change, also filtering the supply of the PC has no effect.
Can you propose a special supply voltage filter? The noise frequency is very low (less than 1 Hz). Other lab cards and electronic devices work properly under the same conditions. Has anyone ever had this kind of problem? Any solutions?
Thank you.
Bernhard

double post
refer to http://forums.ni.com/ni/board/message?board.id=250&message.id=13633
Message Edited by TimoS on 07-06-2005 03:46 AM

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No proper signal with NI-4351 card

Hello,
I am trying to use a NI-4351 for temperature measurement (together with TX-68T connector block). However, I don't get a proper signal in our laboratory. Using the MaX and looking at the test panel: there is sometimes the right voltage but most of the time the signal is noisy or even more than that: it is jumping to the maximum and minimum of the voltage range (for every voltage range).
In an another building with another supply circuit the signal is okay. So we suppose an EMC problem: Together with the Elec. department we have disconnected all "critical" consumers- no change, also filtering the supply of the PC has no effect.
Can you propose a special supply voltage filter? The noise frequency is very low (less than 1 Hz). Other lab cards and electronic devices work properly under the same conditions. Has anyone ever had this kind of problem? Any solutions?
Thank you.
Bernhard

okay, but I don't know how to do it. Is there any possbility to do this in the MAX? Or can I access the card directly (without MAX?)? Or do I have to check hardware pins? Because at the moment I am using 2 virtual channels to make a readout in LabView and these virtual channels are not representing a real hardware information.
Bernhard

TC measurements with PXI 4351 DAQ Card

(I am using version 6i of LabVIEW). I am trying to create a VI that will use a PXI 4351 Card with a TBX-68T to take 4 thermocouple continuous measurements. I am also acquiring 8 voltages with a 6030E and TBX-68 and writing them to a file. My voltage data acquisition is modeled after "Buffered Continuous Analog Input.vi" I would like to aquire voltages and temperatures in the same vi, but using different devices and accessories. (I need a higher frequency for the voltage acquisition, and more precision with the temperatures). Is there a subvi I can use to collect the temperature data in the same vi as my voltage? I don't want the thermocouple DAQ to interfere with the voltage DAQ, either.
I tried the NI435x thermocouple.vi
but I couldn't get the Built-in Cold Junction Sensor to work or figure out how to combine it with my exisiting voltage acquisition. I also got NaN for my readings, and I checked the wire connections in all the sub vi's as suggested by another solution.
Any comments would be great. Thanks in advance.

Claudia-
Thanks for the response.
Regarding the CJC- When I switch it on, the temperature readings I get are very random, roughly negative 1 degrees. (I am operating right now at room temperature, and will be using J-type TC's to measure ~43 degrees C). Also, when I use the built-in CJC, the aquisition rate seems to slow down considerably. When I use the "user specified" everything seems to be ok, including the aquisition rate.
I measured the resitance of the Thermistor on the TBX-68T and it was about 5000 Ohms, as expected.
Just to make sure: When using the TBX-68T, do I need to hard-wire a thermocouple to Channel 1/auto-zero and another to channel 0/CJC? Because I connected a TC to channel 0 right now, but I wasn't 100%
sure.
I've attached my main vi and two sub vi's that I am using for the voltage aquisition part of my project. (Note:the current measurements are just voltage measurements multiplied by the recipricol of the resistance it was measured across, ie. 10).
I would like to keep this file as is because it writes to a file exactly the way I want it to. I'd like to have the temperature aquisition with the 4351 in the same vi as the 6030E so that they both stop and start at the same time. I am just not sure how and where to log the temperature data since there will be fewer data points than the voltage data. Any suggestions? Should I write two separate files? can I somehow append them?
Thanks again. Hope to here from you soon.
Attachments:
EBlackMainDAQ.vi ‏107 KB
Save_Data8.vi ‏45 KB
Build_String_Array5.vi ‏33 KB

I am searching a VI for AC acquisition with a PCMCIA DAQ card 6024E

Hi,
I am searching a VI for Alternativ Current acquisition with a PCMCIA DAQ card 6024E.
I have tried several availble examples but they are unfortunately not compatible with this card.
I am a beginner with Labview, as a consequence any help and support on that topic would be really appreciated.
Thanks,
Alban Cotard.

I think you wann measure Alternating Current?!?
what want you know, the period, amplitude, rms.....?
e.g. use the "cycle average and rms.vi" or other VI in this palett
regards timo

Data-acquisition with NI 6036E DAQ card & GPIB using an external trigger

Hi all,
I hope somebody could give me some help with the following and answer some questions:
Simple system description:
Labview 6.1
PCI-GPIB card
6036E DAQ card
In my system, I am using an external analog trigger signal (A) for continuous data-acquisition. Characteristics of the analog trigger signal (A) are: ~40 Hz, signal height +1.48V, triggered by rising edge (the analog trigger signal (A) could be changed to a TTL signal). Each data-acquisition is done within ~1.0 ms after the rising edge of the trigger pulse. The timing of the data-acquisition and analyzing procedure is controlled by execution in a sequence structure placed in a loop.
Now, I connected a power meter to the system, to measure the laser power during the data-acquisition. The power meter has two options to provide the laser power data:
a) via analog signal output (voltage corresponds to laser power in watts)
b) via GPIB (direct output reading of laser power in watts).
Problem:
During a certain point in my data-acquisition sequence structure (defined by a frame), I want to use the next occuring analog trigger signal (A) to acquire 1 value from the power meter.
How do I do this in Labview programming for the following two situations?
a) If I connect the analog output from the power meter to an analog input channel of the 6036E DAQ card. The analog trigger (A) would be connected to a second analog input channel (In case the analog trigger signal (A) is changed to a TTL signal it would be connected to the PFI0/Trig input pin on the DAQ card).
b) If I use the GPIB connection of the power meter. The analog trigger (A) would be connected to a second analog input channel (In case the analog trigger signal (A) is changed to a TTL signal it would be connected to the PFI0/Trig input pin on the DAQ card).
An other possibility would be to trigger the power meter directly, so it outputs constantly power meter values at ~40 Hz. How could I than acquire 1 power meter value (at a certain time im my sequence structure) via analog input at DAQ card or GPIB?
Additional questions:
How do I configure the PFI0/Trig pin on the 6036E DAQ board individually as an INPUT?
How do I use an analog trigger signal (A) as counting signal for a loop, or as an activation signal for a sequence structure which includes GPIB commands?
It would be very nice if somebody could give me some help.
Kind regards,
beam

Hi beam,
I just want to verify that I understand your situation correctly:
An external trigger signal (A) is wired to one of your input channels (e.g. CH0) to trigger data acquisition of a second channel (e.g. CH1). Your power meter is connected to an analog input channel, which you would like to trigger with a certain rising edge at some of your sequence structure.
Problem:
During a certain point in my data-acquisition sequence structure (defined by a frame), I want to use the next occuring analog trigger signal (A) to acquire 1 value from the power meter.
How do I do this in Labview programming for the following two situations?
a) If I connect the analog output from the power meter to an analog input channel of the 6036E DAQ card. The analog trigger (A) would be connected to a second analog input channel (In case the analog trigger signal (A) is changed to a TTL signal it would be connected to the PFI0/Trig input pin on the DAQ card).
If a task has been configured to acquire signal from one analog channel, it's not possible to run a second analog input task or to add a second channel on the fly. You had mentioned that it's possible to read from the instrument through GPIB. Is it possible to perform a software trigger such that at a certain frame of your structure, when the trigger signal A reaches voltage "x", a GPIB command is written to your power meter to query a measurement reading?
Additional questions:
How do I configure the PFI0/Trig pin on the 6036E DAQ board individually as an INPUT?
You do not need to explicitly configure the PFI0 line as an input. If you want to use it as an input such that it acts as an analog trigger, simply wire the trigger signal to this pin. When configuring the trigger in your software, specify PFI0 as the trigger source.
How do I use an analog trigger signal (A) as counting signal for a loop, or as an activation signal for a sequence structure which includes GPIB commands?
You can try using the Limit VI to find out when the trigger signal reaches a certain level, and count how many times this level is reached. Similarly, you can use this as the condition to execute GPIB commands.
Hope this helps,
Lesley

Frequency counter with E-Series DAQ Card

I am trying to measure the frequency of a signal at 0.1 sec increments using a DAQCard-6062E and an AT-MIO-16E-10. I am using a VI from the examples (frequency counter.vi, in a while loop) which works well with the DAQCard, but it's giving wrong measurements with the AT-MIO card. Why is that?

Hello Waw,
Take a look at this KnowledgeBase to see if it fixes the problem.
http://digital.ni.com/public.nsf/websearch/862567530005F09E8625681C0074935E?OpenDocument
If not, what version of NI-DAQ do you have? Are you getting incorrect measurements with different ranges of frequencies? Is LabVIEW giving you any errors? Do any examples provide correct results with the AT-MIO-16E-10? Please let me know if you have any questions. Have a great day!
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National Instruments

Mac G4 crashes using continuous generation with PCI-1200 DAQ card

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I've tried slow signals (10Hz) and fast signals (2kHz) but the computer still seems to crash. I have no clue what is going on!

bissdp,
The first thing I would recommend is making sure you have the latest version of the driver:
www.ni.com > Support > Drivers and Updates > Current Versions > Multifunction DAQ
Another you could try is to determine what component is causing the computer to lock up. Use a process explorer utility to try to see what processes are locked up. A search in google might turn up utilities like this one: (http://www.clarkwoodsoftware.com/peekaboo/)
Keep in mind heat or speed issues. It may sound funny, but you may want to try opening the computer case and making sure the board has enough air flow to keep it cool.
These are just some ideas for now, I hope they help.
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DC Motor Controlling with ANSI C & DAQ Card

Hello,
I have 2 DC motors and a sensor. I have a NI Daq Card and i have a NI Connector board. I am trying to control DC motor with based on sensor values. Based on the conditions motors should move forward or backward. I am also using motor driver, i already connected my DAQ Card to computer and Connector block and i connected my motors to motor driver and my motor driver to connector block. And i also connected my sensor to connector board.
I gave you a HIGH LOW example which is ritten in PIC BASIC. What i am trying to learn is how i will write in ANSI C and use with DAQ card. And with which function i can read the value of the sensor? Normally if i read port in PIC Basic i will easily read the value.
I checked the DAQ CARD ANSI - C Examples but they aren't too clear. So this i just wanna ask someone who know this.
And to show what i exactly mean, here are some code written in PIC BASIC
INPUT PORTB.0                          ; Light Sensor
OUTPUT PORTB.3                     ; Left Motor Forward
OUTPUT PORTB.4                     ; Left Motor Backward
OUTPUT PORTB.5                     ; Right Motor Forward
OUTPUT PORTB.6                     ; Right Motor Backward
; to make code easy to read we are defining symbols for our ports:
SYMBOL             LSENSOR                 PORTB.0
SYMBOL             LMOTORF                 PORTB.3
SYMBOL             LMOTORB                 PORTB.4
SYMBOL             RMOTORF                 PORTB.5
SYMBOL             RMOTORB                 PORTB.6
Our functions:
TURN_RIGHT_FORWARD:
HIGH   RMOTORF
LOW   RMOTORB
LOW   LMOTORB
LOW   LMOTORF
TURN_LEFT_FORWARD:
HIGH   LMOTORF
LOW   RMOTORB
LOW   LMOTORB
LOW   RMOTORF
GO_STRAIGHT_FORWARD:
HIGH   LMOTORF
HIGH   RMOTORF
LOW   LMOTORB
LOW   RMOTORB
GO_STRAIGHT_BACKWARD:
HIGH   LMOTORB
HIGH   RMOTORB
LOW   LMOTORF
LOW   RMOTORF

Hey there,
I noticed that you have posted here (http://forums.ni.com/ni/board/message?board.id=250&message.id=31497) and got some answers
Might be worth sticking to that forum.
AdamB
Applications Engineering Team Leader | National Instruments | UK & Ireland

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How do i create 6 digital 25Hz PWM output signals with my PCI-6221 card?

Hi!
I´m a student, who´s trynig to control a gasturbine process for my diploma thesis. The control program should be written in LabView 8. I need to control 6 25 Hz PWM signals for the gasvalves. The needed accuracy of the duty cycle has to be about 0.1 %.
A tech. engeneer from NI told us , that we can do this by using one single digital output for each PWM.
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Here you can find an example, how to do this:
http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=DE27921DB53A4D8DE034080020E74861&p_...
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DAQ card works with NIDAQ test panel but not with VB app/Component works

I am seeing this problem with 2 different DAQ cards. The card works fine with the NIDAQ test panel, but acts like the return lead is lifted with my VB app. The plotted signal appears to be little more than noise. Channel scan is internally triggered; that apparently works fine. The VB app is running in this configuration successfully in other areas, and I fixed this problem once by swapping cards. Currently, I lack a spare, as my "spare" is showing the same symptoms. Any helpful hints?
Card type: AT-AI-16XE-10
Configuration: Double-ended input, +/-10V range
Running: VB6, NIDAQ 6.1, ComponentWorks Std. 2.0.1, Windows NT 4.0 SP5

I upgraded to NI-DAQ 6.8.1 (with patch), but no joy. The upgrade went smoothly, the card was recognized and I was able to set the resources without a problem. The test panel works fine looking at the actual signal on the target system: slowly varying DC between 0-5 V or so. My app works fine also, except that it behaves as though the A/D is not connected to anything: noise between .05-.1 V or so. I swapped DAQ cards between the test system and my development system. The problem appears to be in the test system, not on the card. Another test system, identical except for (now) the version of NI-DAQ, works fine. I'm stumped!
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How can I control a stepper motor drive using a DAQ card?

I need to control a simple CW/CCW stepper motor drive using a DAQ
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Cheers,
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What DAQ card do you have? Ideally, one with a counter output to generate the steps, where you can control frequency. If you try to start the motor too fast (acceleration or abrupt application of fast pulses) it may stall out. Search in Help/Search for Examples for 'frequency' and 'pulse' for example of frequency generation. You can also use a digital output on the DAQ card to control direction.
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~~~~~~~~~~~~~~~~~~~~~~~~~~
"It’s the questions that drive us.”
~~~~~~~~~~~~~~~~~~~~~~~~~~

DAQ Card is inducing noise on an external clock signal resulting in false triggering

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3) Cursed at various inanimate objects (made me feel better but didn't help the situation)
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5) Swapped my card with a card of a different type (problem is still there)
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Hello OSU_Mech_Eng,
I'm not quite sure how the DAQ card could be inducing glitches into
your digital signal. Digital signals from mechanical devices like
quadrature encoders can often be glitchy or bouncy, but your schmitt
trigger should act as a debouncing filter to clean up that digital
signal. It sounds like you have thoroughly troubleshooted this
problem, and I would recommend moving on and trying to use a counter on
your DAQ board to generate the digital signal, rathar than using the
raw signal from your encoder/schmitt trigger.
You were correct when you stated that the best way to do this is by
configuring your counter to perform retriggerable pulse
generation. You can use the signal of from your encoder to gate
the internal clock on your DAQ card, creating a clean digital
signal. By setting the minimum pulse width of the signal, you
will be able to ignore the small glitches in your signal. Here is
a link to some Knowledgebases describing how to do this:
How Do I Remove Glitches or Add a Debounce Filter to My Digital Signal?
How Do I Define the Parameters for Pulse Generation in NI-DAQmx?
For further reference, on all of NI's new M-Series DAQ cards (PCI
625x), the PFI circuitry contains built in debouncing filters to
protect against small glitches in digital signals. If you have an
M-Series card lying around, it might be helpful to give that a try.
I hope this helps,
Travis Gorkin
Applications Engineering
National Instruments
www.ni.com/support

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
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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

No proper signal with NI-4351 DAQ-card

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