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external digital input start and done events

November 5, 2015, 8:12 am
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Dear NI members,

 

we are working on a microscope driving application, written in C by using the NIDAQmx driver. We create a digital input task and we asign a Change Detection event for it. From the microscope a 8kHz signal will arrive every time the scanner starts acquisition and that signal will stop after acquisition is done. To detect the start point we are looking for the first change in signal from low to high. We are having issue of detecting the end point, as the number of 8kHz pulses sent by the scanner can be different. What is the best way to detect that the signal is not arriving anymore? 

The card we are using is NI PCIe-6321.

Thank you in advance for any ideas.

 

Best,

Georgi

 

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Error 363513 occurred at niFpgaCompileFarm_UploadFile.vi

November 9, 2015, 2:12 am
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I am quite new to the FPGA programming with cRio and Labview, and I tried my hands on a minimal program which reads out a channel on the NI9403 (digital module). In my program I've connected this up to a Boolean indicator.

Image may be NSFW.
Clik here to view. Capture.PNG

I've put it in a .VI directly under the FPGA target. The rest of the project is straight from the FPGA template.

Image may be NSFW.
Clik here to view. Capture2.PNG

 

When I compile this program, using a NI compile farm, I get the following error:

 

Error 363513 occurred at niFpgaCompileFarm_UploadFile.vi

Possible reason(s):

LabVIEW: An error occurred while sending data on the network.


Complete call chain:
niFpgaCompileFarm_UploadFile.vi
niFpgaCompileFarm_UploadFile.vi.ACBRProxyCaller.3CC00086

 

It happens during, or right after the "Transferring files to the compile server" phase, as far as I can tell.

 

Any insight on what is happening, and what to do?

 

cheers,

Arvest

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prevent NI write named waveform from enabling sample clock until initiate

November 10, 2015, 6:52 am
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Hello,

 

I am attempting to use the NI HSDIO-6652 sample clock (on-board clock is clock source) exported via DDC CLK OUT to act as the clk_in for a simple logic circuit on an external DUT. The logic on the DUT is a long shift register which shifts data at the rising edge of it's clk_in input. The issue I am having is that when niHSDIO Write Named Waveform.vi executes the sample clock enables before the labview code has even executed the NiHSDIO Initiate vi (this was observed on oscillosope). Since the shift clock for the DUT is the sample clock I end up losing data in the shift registers. I need to be able to shift in a data for exactly X clock cycles.

 

Is there a better way I could be doing this or is there a way to export the sample clock only while the active data event is occurring? Or is there a way to have the start trigger follow the sample clock? 

 

Thanks,

Scott

 

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Unit °C^-1

November 11, 2015, 7:05 am
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Hello,

 

in my VI I want to calculate the concentration of water with the help of this:

 

Image may be NSFW.
Clik here to view. \frac{D_{\rm LF}}{\rm g/l} = \frac{a_0 + a_1 T + a_2 T^2 + a_3 T^3 + a_4 T^4 + a_5 T^5}{1 + b T}

 

And I want to match the right units. I know the temperature is "degC" but how can I commit the unit "1/°C" to LabVIEW, because the constants (a0, a1 ...) have this unit.

Can you help me?

 

Thank You

Regards

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USB-6501 Operation

November 12, 2015, 7:24 am
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Hello all,

 

I have a brand new NI USB-6501, and I'm looking for some help with operation.  I am running OS X 10.11.1, LabVIEW 2013 SP 1, NI-VISA 15.0, and NI-DAQmx Base 15.0.0.  I set up and plugged in my module and get a steady blinking green light.  I ran NI MAX, found the module and renamed it "Motor_Module".  I then went to my DAQmx Base Examples and found the USB-6501 Interactive Control.llb and ran the interactive control VI that is contained in that library.

 

The first thing I tried was simply running the VI.  I got Error -200220, Device identifier is invalid.  I changed Device Name to "Motor_Module" and ran the VI again.  This time, I got Error -200558, One task cannot contain multiple independent devices.  Create one task for each independent device.

 

And this is where I stand.  My end goal is to have this module output an open-collector type signal at +5 V.  Any help would be greatly appreciated.  Thanks.

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how to enable the digital input filtering feature of NI USB 6525

November 12, 2015, 7:36 pm
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How could i enable the digital filtering feature of an NI USB 6525?

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how to connect yokogawa wt3000E with labview using USB

November 12, 2015, 10:48 pm
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Hi,

    I'm working on a project, i need to interface Yokogawa WT3000E with Labview 2013 using USB Interface, I have downloaded labview driver for yokogawa and USB Driver, I searched through the net and found that WT3000E needs .inf file for interfacing, I created .inf file using NI-Visa, But in Visa Resource name i was not able to find it. Suggest me wth a solution.

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Alternative free software

November 15, 2015, 5:47 pm
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About a year ago my school was cleaning out a bunch of old stuff and they had some old NI SPEEDY-33 boards. Thinking they might be useful I grabbed a couple of them. After playing around a bit I realized that there was no way to activate the DSP module for labview because my school lost the activation code. Is there any free software that can be used to program these things? os and programming language are not an issue, I can learn.

 

If there is not a way, is it possible to contact labview about activation codes for EOL products at a discount?

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Programmatically generate a single hardware timed pulse PXIe-6363

November 17, 2015, 9:55 am
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Hi

 

I use C# but any language besides LabView is fine.  I would like to programmatically generate a hardware timed pulse of programmable duration from 1µs to 1000 ms in duration.   I have a level shifter to bring it to 3.3V.   I have PFI12 (cntr0) available.  I want both rising and falling edge which is implied by the duration but just to be clear.   I was successful at creating an edge but not a pulse.  It would be nice, but not necessary to define the number of pulses.  

 

Thanks for your help.  There are a number of reasons I choose NI equipment but one of the big ones is the support.  Most of the time I get the answer I need the first time.  Documentation says to set the timing to finite but I must be doing it wrong as I get only a rising edge.  

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daqmx testpannel

November 18, 2015, 7:18 am
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Hello

 

In our application we use a PXI-6509 board. During debugging we make use of the testpannel in Measurment and Automaition Explorer.

Our problem now is that when our programm runs we can not use the testpannel of the PXI-6509.

Our idea now was to make a local client/server  application where the server communicates with the DAQmx driver and our testprogramm runs as a client.

We can also monitor the state of the IO with an external pc. This is a big adavantage for use.

 

But before we start building a client/server appliation. Is this already a feature in the latest version of Measurment and Automation Explorer ?

 

 

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Implementing I2C Clock Stretching in HSDIO

November 23, 2015, 4:00 am
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Hi All,

 

I've successfully implemented I2C Read and Write using NI I2C Library for HSDIO PXIe-6556. I understand how clock stretching in I2C works, but I'm confused on implementing it for HSDIO. Any insights or suggestions will be helpful.

Thanks in advance.

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NiFpga Poke Function

November 23, 2015, 8:29 am
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Hello - it appears the NiFPGA_WriteXX functions perform the write and then verify that the write succeeded.  Is there a way to perform a "poke" type function, where the write is performed but not verified?

Thanks.

 

I am workng with a PXI7811 instrument.

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NI 7845 Board

November 23, 2015, 11:36 pm
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When I useed NI-7845R board.I found have +5V connection,Who is know what to do is it? is output +5V or input +5V? Other I found have much GND connection and ADND connection,I want to know dufference about it.Does anyone know? 

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USB-6501 Voltage at Random Outputs

November 24, 2015, 5:10 am
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I have my USB-6501 plugged in, and without running a program, I have +5 V at a bunch of random pins.  Even stranger, if I unplug it and then plug it back in, the pins that I have voltage at will change.  Right now, when measured with the negative probe at ground, I get +5 V at pins 0.0 (fluctuating wildly), 0.2, 0.3, 0.6, 0.7, and 2.7, but not at either of the +5 V supply pins.  Anyone have any idea what that's all about?  I know I am communicating with the unit because, although I can't seem to control what pins I get voltage at, I can change that voltage between +3.3 V and +5 V

 

I'm also trying to see if there's a way (for digital output) to set the signal frequency, pulse length, and time between pulses?

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power excitation for solenoid valves

November 24, 2015, 2:21 pm
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Hi,

 

1. I need to select  a right module for exciting solenoid valve which requires 24DC  V.  As per the forums, The maximum voltage that can be provided is 10V from NI 9237.  

 

2. Also I need to operate 8 solenoid valves simultaneously. Can anybody suggest ?

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24 v digital out signal from host event to fpga turning on and off

November 25, 2015, 2:20 pm
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Hello Ni forums 

 

Hardware Specs

 

crio 9074 

c series module ni 9472 module digital 24 V output

 

 

To expand on the subject describes,

 

I want to be able send an alarm trigger to the fpga 9472 digital out that lasts for 30 seconds using the real time os clock time on the host

 

 

 

The way I approached this problem is that 

 

In the loop where the event occurs , if the event trigger is set then the fgv has a time stamp of when the event occured is sent.

In the loop that communicates with the fpga control, I write to the control based on the condition that if the difference the of the current time checked and the time from the fgv is less than or equal to 30 secs then it will send a true value, else  send false and wait for the next event occurence.

 

The main problem after implementing this is that the 9472 led does not turn off when a false value is send to it.

 

regards Mzamanstl

 

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how to speed up mydaq digital output

November 26, 2015, 9:53 am
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Hi,

 

I am controlling a unipolar stepper motor through a Mydaq using digital write to pins 0-3.  It is SLOW!  Is there any way to speed this up?

 

thanks in advance!

 

Brian

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HSDIO StartTrigger Dynamic Generation Delay

November 30, 2015, 11:41 am
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I have a PXI-6541 card that I am using to trigger output on a PXIe-6341, using the nihsdio c# wrapper. The 6541 card is configured to be software-triggered and sends a start trigger from PFI0. To test the timing between the two cards, each card outputs a digital pulse on one channel 1ms after the start of the sequence. What I've found is that the 6341 card starts the pulse exactly 1ms after the trigger, but the 6541 card has a fixed delay of around 300us with a sample clock if 100 kHz. This delay increases by a factor of 10 when I reduce the clock frequency by a factor of 10, which makes me suspect it involves the number of clock cycles. The sample clock from the 6541 card, which is derived from its onboard clock, is routed to the 6341 card. I have checked the sequence that is being written to each card and the channel goes high at the same sample index. Is there a way to output a trigger after I call the Initiate() method to see when the sequence starts on the 6541 card or a better way to ensure both cards are triggered at the same time?

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Program DO-24V and DIO TTL-5V signal with wait time in a flat sequence

December 3, 2015, 3:19 am
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Hi All,

 

I am new to programming DO/DIO. Basically I want to control 2 FET using DO and they take a signal of 15V/0V and 5V/0V to switch on and off. So I am using 1 DO-24V (NI 9472) and 1DIO 5V TTL(NI 9403) for this purpose.

 

I am able to switch both the signals on and off when I am pressing on the bolean switch but when I try to program it using flat sequence to make it a timed event of switch on and off, it doesn't work. The front panel shows the signal changing but it is not executing the signal. I have connected a voltmeter to check the signal which is coming out of both of the DO. 

 

I am attaching all the files associated with it. 

 

It will be great if someone can help me in this.

 

Specifications:

cRIO-9114

Labview-32bit-2010

DO-24V-9472

DIO-5VTTL-9403.

 

Please let me know if you need any more information.

 

 

Regards,

Gaurav

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NI USB 6525 Digital Input Signal Voltage

December 10, 2015, 1:45 am
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I have connected my circuit as in the attachment. From the voltage divider, i should have get a voltage reading of around 4.8V(LOGIC HIGH) when my X06 signal supply is 24V DC. However, i can only get a voltage reading of 1.8V(LOGIC LOW) when i measure the voltage at port 1.0+ and 1.0-

Anyone face the same issue as mine? How to solve the problem? Please advise. Thanks.

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