Synchronisation issue between output signals generated by two tasks

February 2, 2017, 2:01 pm

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Hello everybody, 

 

Here is what i would like my PXI 6259 generates : 

- t0 : 

    - a 62,5 kHz digital output pulse data signal (on port0/line1) 

    - a digital signal S1 at +5v output (on port0/line2)

 

-t1 :

   - stop the 62,5 kHz output

   - stop the S1 signal (from 5V to 0V output)

 

I'm using the C API and here it what I made to generate that : 

- I have created a task for the counter (62,5 kHz)

- A task for the pattern data signal

- A task for S1 signal

 

All task are already started.

 

At t0, i write the samples to the pattern task, and I set the output to 1 for the S1 task.

At t1, i writle 0 for the samples to the pattern task and i set the output to 0 for the S1 task.

 

The generation works fine : data and my S1 signal are correctly generated but I have a delay

- between the S1 to +5v and the start of the data output (the data start sometimes after S1 and sometimes before)

- the stop of the data output and S1 to 0v (same issue, S1 could stop after or before the data but never in the same time).

 

It is an issue for me.

 

I would like to both my data and my S1 signal start to output at the same time and stop at the same time.

 

I have tried another design : 

at

- (t0 - offset) : write the samples in my pattern task

    - start the pattern task

    - set the initial delay to offset for the counter pulse

    - start the counter task

 

- t0 : write 1 to the S1 chan to have the output at 5v

 

t1 :

- stop pattern and counter task

- write 0 to the S1 chan to have the output at 0v

 

It arrives that the delay pulse is not respected and the data task start its output while the S1 output is not as yet generated.

 

Would you have an idea to synchronise my both output : S1 start emitting at the same time as my data, and both stop at the same time ?

 

Thank you for your help and idea.

 

 

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How to determine which simulated device to use?

February 3, 2017, 12:13 pm

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I am trying to create VIs for different instruments (e.g. force gauges, thermocouples, strain gauges, etc.) but don't usually have acces to the instruments as they are usually in use by others with a higher priority or I'm working at home where I don't have the instruments. I want to use the simulated device feature of MAX but there is such a long list of options I have no idea which one to choose. I randomly choose a couple of options but when I tried to make a task for the force gauge it said that there where no supported devices.

 

I was wondering if there was a way to determine which option I should choice when making the simulated device so that it registers as a supported device for what I'm trying to simulate. Is there a document or reference that would have this? None of my google searches have been fruitful.

 

I will eventually be using the DAQmx VIs but my initial test have all been on MAX.

USB6009 Digital Input : Problem to acquire logic signal

February 6, 2017, 7:57 am

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Hi,

I need to acquire 3 signals.
I use Digital Input from USB6009

2 signals (P0.0 & P0.3) are periodic square 180µs (UP then down)
The third signal (P0.2) is not periodic but has High Level during 90µs then low level during approx. 100ms.

With my program, I never see high state from non-periodic signal.
Is it normal ?

DDC CLK OUT of PXIe-6556

February 7, 2017, 3:30 am

≫ Next: Controlling a digital output channel with Metamorph

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Is it possible that clock on DDC CLK OUT of PXIe-6556 can not be continious? For example, if necessary generate only N-periods of clock.

Controlling a digital output channel with Metamorph

February 7, 2017, 7:38 am

≫ Next: Alternative voltage generator to USB-6009

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Hello everyone,

 

I am using a NI USB-6501 Board to toggle the shutter of my lab (XCITE DC200). This is working perfectly fine with the MAX software. For my experimental designe I need to toggle it within Metamorph though (to achieve a more accurate toggle), and there is an metamorph extension I can use to access it. Yet it does not have an effect when i toggle the selected pin within metamorph. I am using version 16 of the MAX software.

 

Does anyone of you have experinces with that?

 

Thank you for your help!

Alternative voltage generator to USB-6009

February 8, 2017, 10:37 pm

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Hi everyone,
I am using USB-6009 in order to control the voltage across 5 identical LEDs in parallel through using labview which will be later on used for PID temperature control ( the connection can be changed to series if u suggest any other solutions). Each LED needs 30mA and 5V. The USB only provide a maximum voltage of 5V and 5mA. Is there any alternative NI control hardware that I can use instead of the USB-6009 that is more efficient for generating enough voltage and current for my application? Or if you know of any alternative circuit connection for fulfilling my application?
Thanks

When I set an FPGA I/O pin high, the voltage goes high then decays

February 10, 2017, 8:43 am

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Using the Front Panel of my LabVIEW FPGA program, I change an FPGA I/O pin from low to high.  I look at the signal on a scope and find that the output momentarily goes high and then decays.  I can't figure out why its not staying high.  The block diagram below.

Software Version: LabVIEW FPGA Module 2016

Hardware: NI PXIe-7020R

Replacement for PCI-8335 MXI-3

February 10, 2017, 2:02 pm

≫ Next: Problem with scripted waveform generation HSDIO

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I'll looking to rebuild an industrial PC that currently has a NI PCI-8335 MXI-3 card in it.  This card is connected via fiber to a NI PXI-8335 MXI-3 card.  The new PC's OS will be Windows 10.

 

Can you still buy the NI CI-8335 MXI-3?

Is there Windows 10 support fo the NI PCI-8335 MXI-3?

 

If not...  Is there a replacement for the NI PCI-8335 MXI-3 card that 

1.  Is supported in Windows10

2.  Will still talk to the NI PXI-8335 MXI-3 card?

 

Do I have to replace both cards (PCI-8335 MXI-3 and the PXI-8335 MXI-3)?

 

Thanks,

 

James

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Problem with scripted waveform generation HSDIO

February 14, 2017, 11:10 am

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Hello all,

I am using a PXIe 6541 card to dynamically generate a sequence of waveforms using a script. With a clock frequency of 10 MHz, my test script looks something like

 

script myScript

generate waveform0
Repeat 400
generate waveform1
end repeat
Repeat 400
generate waveform2
end repeat
Repeat 400
generate waveform3
end repeat
Repeat 200
generate waveform4
end repeat
Repeat forever
generate waveform5
end repeat

end script

 

when I run this script, I get the output that I expect from the programmed waveforms and repetition times.  Each waveform is an array of 4 samples that changes the state of one channel to pulse it on and off. However, when I increase the loop times by a factor of 25, I only see one pulse, as if the full script is not being generated. The card should be able to handle this many repetitions, so I am not sure why it cannot output the script if I increase the number of times each waveform is repeated.

 

Many thanks,

Jimmy

daqmx start digital edge retriggerable from counter output

February 14, 2017, 2:27 pm

≫ Next: Changing voltage level Digital output NI9477

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using daq-mx (labivew 2012)  and two counters, ctr0 is 1000 Hz, continuous samples with pause trigger coming from ctr1 at 20 Hz, continuous samples, obtaining continuous 1000 Hz bursts at 20 Hz.

 

We need to generate a finite number of bursts.     Can a third counter,   ctr2 be used to trigger ctr1, reconfigured as retriggerable with a start digital edge, being gated by ctr2 output?   

 

could a fourth counter, ctr3,  be used to count the number of bursts and stop generation after a predetermined number of bursts?      

 

This would be using a pci-6601  or pci-6602    digital board.      the 6601 only has 1 dma channel, the 6602 has 3.     would there be any problem using the 6601 as fairly low frequencies, under 1000 hz?

Changing voltage level Digital output NI9477

February 16, 2017, 7:03 am

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I need to actuate solenoid valves which operates at 12V DC. All valves are connected to Digital Output Module 9477.But how do I set voltage output level of Digital Module as 12 Volts

NI PCIe-6536B digital I/O - hardware & software (NI-DAQmx driver) installation issue

February 16, 2017, 12:09 pm

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I have started working on a development system that has had a NI PCIe-6536B digital I/O card installed. Also installed is the NI-DAQmx 16.0 driver software. However, I am unable to find my NI PCIe-6536B card under Windows 7 or Windows 10 (both x64, both with NI-DAQmx 16.0) in the Device Manager: nothing jumps out at me as being that card. On Windows 10 (x32, with both Traditional NI-DAQ and NI-DAQmx 16.0 installed) I see a device called "PCI Data Acquisition and Signal Processing Controller" and I can even install the PCIe-6536B driver for it and see it in NI-MAX, but it doesn't work. NI-MAX shows error -50150 / Software is in a bad state, and reset/self test/configure all give the same error.

 

From the manual it sounds like the card was supposed to have auto-detected in Windows after installation of the physical media. (a) How should the card show up in Device Manager if appropriate drivers haven't been associated with it yet? (b) Could what I'm seen be caused by an incompatibility between my card and my system, damage to the card or improper installation, etc.? For what it's worth: there is a solid lit green LED on the card.

Can I use DIO port of NI8451 as extra CS lines ?

February 16, 2017, 6:06 pm

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sorry，repeated，please delete this 

Can I use DIO port of NI8451 as extra CS lines ?

February 16, 2017, 6:01 pm

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Hi,

 I have 30 slave devices to communicate, but the USB-NI8451 only have 8 CS line. I am thinking I can use the DIO port as extra CS lines. 

Is that possible?

And then I can use two NI8451s to communicate with 30 slave devices .

cRIO 9002 digital output

February 19, 2017, 9:36 am

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Hi,I'm trying to control some servos for my final project and i'm using labview 8.5, cRIO 9002, chassis 9102, and NI 9472 digital output module. I know it's kind of old but it's what i got. The main problem is that i can't find a way to control the servos using the digital output. I've searched everywhere and i still can't find a way. I'll be very grateful if you could help me, thanks.

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Installation von NI-USB 6008 unter WIN 10 funktioniert nicht

February 21, 2017, 1:18 am

≫ Next: Is there a way to trigger a PXIe-6556 PPMU measurement while the instrument is running a digital pattern?

≪ Previous: cRIO 9002 digital output

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Guten Morgen zusammen,

 

leider ist es uns nicht gelungen, auf einen neuen Rechner mit WIN 10 unser USB 6008 zu installieren (auf unserem alten Rechner mit WIN XP läuft das device und die Software ohne Probleme). Die Software befindet sich (durch den internen Update-Dienst) auf dem neuesten Stand. Das USB device wird im MAX angezeigt, jedoch ist bei einem Rechtsklick kein "Selbsttest" zu wählen. Die Software wird über einen Administrator installiert, bedient wird sie jedoch ohne "Admin-Rechte" (kann das ein Problem sein?). Wir bitten um Hilfe!

Is there a way to trigger a PXIe-6556 PPMU measurement while the instrument is running a digital pattern?

February 28, 2017, 7:53 am

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I'd like to be able to take measurements with the PXIe-6556's PPMU(s) while the instrument is running a digital pattern. While it is possible to output an event trigger from a pattern step while it is running, I haven't found a way to get the event trigger to trigger a PPMU measurement.

Is there a way to trigger the PPMU to take a measurement versus having to halt the pattern and take a measurement?

HSDIO Transmission Line Length

March 2, 2017, 8:13 am

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I need to design a board with a specific transmission line length. When using the 6556 and a 1M cable, how can I guarantee the line length? Where should I assume the start of the transmission line is(Card connector, end of cable, end of connector)?

 

 

SPI Communication using PXIe-6556

March 2, 2017, 12:41 pm

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I routinely have to communicate with various ASICs using mostly the SPI interface and occasionally the I2C bus.  Typical usage would be to write to programming registers in the ASIC or reading back the register values to update fields in my LabVIEW code.  I have built LabVIEW software to do this using the HSDIO driver VIs.  The software is rather complex, and I was looking for a way to simplify it when I came across the SPI Digital Waveform Reference Library. 

 

It was pretty easy and straightforward to put together a VI to write the bits out to the ASIC.  My problem is that I don't see a way to read back the register values from the ASIC and post the values.  The Swap.vi can handle full duplex communication, but does not seem to return the waveform read back from the ASIC.   Nor does the Receive.vi.  Using the HSDIO driver I setup a generation and acquisition session, and program the ASIC for a read operation.  The acquisition session is triggered from the generation session, and then fetches the waveform data from the 6556 memory.  From there I can parse the bits and ascertain what the individual register values are. 

 

My question then is how do I do this using the SPI library?

NI USB-6501 outputs signal when plugging in

March 2, 2017, 6:44 pm

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I received a new USB-6501. After installing software and hardware, I noticed it gave a "on" output signal (and turn on my down stream instrument) when plugging/unplugging USB cable and turning on computer. It is connected to a Dell OptiPlex3040 with Win7 64 bit. It works fine otherwise. Does anyone have similar experience or have a solution?