Digital I/O topics

Pin latency problem in USB 6008

NIRSean — Tue, 21 May 2013 20:48:00 GMT

Hi all,

My team and I are running some cognitive workload experiments using an in-house flight simulator and would like to print the events from this simulator to our EEG data. This flight simulator is MATLAB based and we have adopted the C-based NI-DAQmx shared libraries to output the digitally encoded events through a USB 6008. We are successfully outputting all of the recorded events onto the EEG data but are also picking up some extraneous events. After some careful troubleshooting, we've determined that these unexplained event codes are probably not coming from the MATLAB flight simulator but instead might be a hardware problem from the DAQ. The random events occur within ~1ms of a true event and are always off by a single power of 2. This leads us to believe that one or more of the eight pins in port0 is lagging behind the others, thus holding its previous state for just a slight moment longer than the rest. The EEG software was initially recording at 8kHz, we then lowered the sampling rate to 4kHz and then 2kHz. Even while recording at 2kHz, an extraneous event was detected. This test was also repeated using a sampling rate of 16kHz with the same result of a single extra event. We ran a few more trial through LABVIEW, circumventing the EEG software. The extra events were still observed. None of the extra events occur at the same time instance, even though the flight simulator true events were identical, and extra events are rarely the same decimal value.

The events are coded as decimal 1 to 133 to digital port0 and written using DAQmxWriteDigitalU8 (from the NIDAQmx C reference library). The DAQmx channel is set to be port0 (not pins 0to7 individually). When no event is detected, decimal 0 is output through port0. As soon as a event is written, port0 is immediately returned to decimal 0. The pulse width between trigger on and trigger off is within a few milliseconds. Multiple events occuring within the flight simulator's 100ms refresh window are printed to the DAQ in series.

Here are the basic specs:

EEG system: 16kHz,8kHz,4kHz, or 2kHz

USB 6008 sampling rate: 10kHz

Event pulse width: ~3ms

Flight simulator's refresh rate: ~100ms (with multiple DAQ writes inside this window)

At this time, our best guess is that one or more of the pins are lagging behind, but not always, since we only detected a single extra event for the 16kHz tests. Does anyone have any other theories or possible solutions?

Implement watch dog for USB-6251

ediorz — Tue, 21 May 2013 15:18:59 GMT

Hi,

I am pretty new to NI DAQmx and USB 6251 so I might be asking a question that has a obvious answer here....(also if I should post this question somewhere else please let me know)

I am trying to implement a watch dog timer that will trigger a digital output (static or waveform) to a signal light

From the spec for USB 6251, I can see that it does not have a built in watch dog timer that I can use..

Therefore, is it possible to implement my own watch dog timer (hardware timer not software)using the hardware spec for this device??

I am programming using C# .NET 4.0 which i can see the methods for watch dog but cannot use due to hardware spec..

Maybe my best thing to do is buy a model that supports watchdog??

Thanks in advance,

Edward

Synchronize output state of digital output.

FJ_Sanchez+ — Mon, 20 May 2013 15:20:52 GMT

Hello,

it's my first post here and I hope you can help me. I have 24 digital controllable switches and I want to capture 2 analog signals for each switch when I turn on it. I have the switches grouped into 2 groups, A and B, that are switched with the same pattern but with an initial delay of 10ms or 50ms.

- I have NI PCIe-6351 on Dev1 and NI PCIe-6323 on Dev2.
- Group A is assigned to 16 switches, controlled with /Dev2/port0/line0:15 and captured with analog inputs of Dev2 (32 inputs).
- Group B is assigned to 8 switches, controlled with /Dev2/port0/line16:23 and captured with analog inputs of Dev1 (16 inputs).

Just now I've a pattern generator that generates a digital waveform with the patterns A and B. I load this pattern to a DAQmx digital output task in continuous mode as I've to repeat the pattern N times. Digital output is configured in lines /Dev1/port0:1 and connected with wires to /Dev1/PFI0 and /Dev2/PFI0. Then I create 2 analog read task (one for each device) triggered by PFI0, both captures are in finite mode.

The problem is that I don't know how to configure the digital output task that switches the lines (/Dev2/port0/line0:23). The lines 0:15 should be in the same output state (high or low) that pattern A (output at /Dev1/port0/line0 and input at /Dev2/PFI0) and the lines 16:23 should be in the same output state that pattern B (output at /Dev1/port0/line0 and input at /Dev1/PFI0).

Also, after each capture (I capture a finite number of points) I process them and it could be the case that a switch is maltfunctioning and I've to disconect it, so in the next iteration this switch won't be turned on, and therefor I've to remove this line from this digital output task.

Any idea of how to do this? Any better approach of getting the wanted result?

Thank you.

NI 9401 velocity update problem

vivozhang — Thu, 16 May 2013 07:52:38 GMT

I am using NI 9401, and configured it to Quadrature mode to measure speed of a motor.

The sample rate is set to 2ms. I use a TDMS file to store data, those data are input voltage, speed (in rad/s), and time (ms).

It seems the update rate of the velocity is very low, 10ms, that is 100Hz. I don't know why. Does anybody have the problem or any solution?

Thanks a lot.

30.67961576	3	9616682
30.67961576	3	9616684
30.67961576	3	9616686
30.67961576	3	9616688
30.67961576	3	9616690
76.69903939	3	9616692
76.69903939	3	9616694
76.69903939	3	9616696
76.69903939	3	9616698
76.69903939	3	9616700
117.6051937	3	9616702
117.6051937	3	9616704
117.6051937	3	9616706
117.6051937	3	9616708
117.6051937	3	9616710
153.3980788	3	9616712
153.3980788	3	9616714
153.3980788	3	9616716
153.3980788	3	9616718
153.3980788	3	9616720
178.9644253	3	9616722
178.9644253	3	9616724
178.9644253	3	9616726
178.9644253	3	9616728
178.9644253	3	9616730
204.5307717	3	9616732
204.5307717	3	9616734

Will the NI9423 work with Sound and Vibration VI's

Bodger1968 — Tue, 14 May 2013 10:42:51 GMT

Will the NI 9423 mounted on a cRIO chassis work with the NI sound and vibration VI's ?

I have a 10 -30 V 100 pulse/rev optical shaft encoder and would like to perform angle domain order analysis with it.

is the NI9423 a suitable card for this purpose or is something else better suited, I am open to changing the encoder type if needed.

Temperatura di esercizio 196275-01

pic32mx — Tue, 14 May 2013 07:57:36 GMT

Salve!

Avrei bisogno di utilizzare la cavetteria NI per un test in temperatura da -55°C a +125°C.

Potrei avere informazioni in merito alla temperatura di lavoro ammissibile per i cavi, in particolare 196275-01?

Grazie!

Michele M.

Windowing and counting the number of edges

tintin_99 — Mon, 13 May 2013 19:09:26 GMT

Hi for a project I am continuously acquiring a signal . The signal contains Sync bit and Data bits. The pattern is attached to this email. After finishing acquiring I would like to extract the data . The method in my mind is to use a window ( the same widths of the data window and count the number of rising edges and falling edges and if it is equal to the number of RE and FE in data window I can say that window is my data window. then I save data

Could you please help me using this method. Do you think is it a good method and how can I implement this windowing and counting the number of edges in LabVIEW/. my input is a digital waveform

My program works on arduino MEGA well, but doesn't work on arduino UNO .. why?

Khaled88 — Fri, 10 May 2013 08:13:18 GMT

The program to write digital output via boolean control, this program works on Arduino MEGA well, but on UNO, there is no output on pin 8 .. why?

continuous digital output using USB-6211

tim_wen — Thu, 09 May 2013 17:38:09 GMT

Hi,

I am trying to use the LV example "Cont write dig port - Int clk.vi" to generate a pattern.

But I keep getting the -200077 error about the sample clock. The pop-up error message suggests

using "on demand", but there's no such choice with the DAQmx.

Any hint? Thanks.

OM-USB-1208FS isn't recognized by LabView.

TomEdelhoff — Thu, 09 May 2013 17:00:48 GMT

I am using an Omega OM-USB-1208FS and LabView 2012. I can't get LabView to recognize the device. I have seen that someone is the forum has already used this device with LabView: http://forums.ni.com/t5/Digital-I-O/port-format/m-p/2095126 . I have used this device with TracerDAQ with no problems. The ULx for LabView has been installed. I have Visa 5.3 Any ideas?

read digital waveform through single DIO line

tintin_99 — Wed, 08 May 2013 22:01:21 GMT

Hi I have currently purchased NI DAQ USB 6363 to accquire serial digital waveform. I'd like to read serial digital data through one of the digital IOs with data rate of 45 kHz. Please see the attached for the data frame. Could anybody comment one the feasibility of this? Is there any example codes that I can refer to?

USB-8452 as fast SPI slave

Mario79 — Wed, 08 May 2013 21:34:08 GMT

Hi! I have the USB-8452 and i need to use it as fast SPI module (12MHz). It is possible? If yes, where I can find some information? If no, have you plan to develop this feature?

Connecting a rotary encoder to 9923

Nasim — Tue, 07 May 2013 13:02:10 GMT

Hi,

I am trying to connect a rotary encoder (Model VERT-X 13E version B) to NI 9923 and ultimately to NI 9403. I can not figure out how I should connect the wires. Which slots are designated for the positive and which ones are for the negative. This encoder is suppose to read the position of a piston . It is installed on the flywheel. I have attached the info about the encoder. I tried different set of connections but it doesn't work.

Any help is appreciated

Thanks

Using FPGA Targets in a LabVIEW Project (FPGA Module)

sfla — Tue, 07 May 2013 07:01:51 GMT

Hi, I'm trying to add an FPGA Target in the Local Development Computer according http://zone.ni.com/reference/en-XX/help/371599H-01/lvfpgahelp/adding_an_fpga_target/

Here are the steps :

Create a new project or open an existing project.
Right-click My Computer in the Project Explorer window and select New»Targets and Devices from the

But I do not find Targets and Devices in the menu New. I have only this window (see attached file).

Is there something to do before ? I have installed the FPGA module.

Thanks for your response.

Looking for a solution to resolve an error (-1074118624)

kunmok — Mon, 06 May 2013 21:38:09 GMT

Hi,

I'm getting the following error while running DIO data generation and acquisition:

-1074118624: niHSDIO Fetch Waveform (1D U32).vi<ERR>Driver Status: (Hex 0xBFFA4020) Some or all of the
samples requested have not yet been acquired.
To wait for the samples to become available, use a longer read timeout or read later in your program. If
your session uses a trigger, make sure that your trigger is configured correctly.

generation session is using two DIO cards (PXI 6551 and PXI6542) and acquisition session is using only one DIO card (PXI 6551)

Does anyone know how to resolve this error?

Thank you,

Labview fpga(on/Off) relay operation

aalg — Mon, 06 May 2013 19:56:02 GMT

Hi all,

I am using pci 7811R with break out box(SCB68) and ERB48 Relay. I will like to write FPGA vi for the operation of the Relays. These relays are controlling the unit under test. The UUT is wireless product so there is Freq, RF,Power, Voltage...There are different Relays on and off the when the UUT is being tested. My questions is I am not sure if I am keeping relays that was supposed to be on or off the right time. Not too much exprience in Labview and Labview FPGA. Will appreciate any feedback. attached is sample of the Relay operation vi in my project.

Thanks,

Aalg.

Upgrade from NI-DAQ legacy to NI-DAQmx

Magued — Mon, 06 May 2013 19:40:26 GMT

Hi,

We have a large system that is developed in VB and uses the traditional NI-DAQ legacy system. The system uses VB6 and windows XP.

We would like to upgrade to Windows 7 with the least amount of changes.

1) Do I need to download the latest driver? And what is the version number?

2) Would the latest driver be compatible with VB6?

3) Are there any major hardware changes that will be required?

Thanks, Magued

NI 9236 Dehnungsmessung

ohr — Sun, 05 May 2013 15:20:05 GMT

Ich möchte Dehnungen bzw. Spannungen eines Objekts mittels DMS messen und habe die NI 9236 Module sowie die cDAQ 9178 bzw. 9174 zur

Verfügung. Eine generelle Frage: Kann ich meine DMS/Rosetten direkt an das Modul anschließen oder muss ich diese zuvor in einer

(Viertel-)Brückenschaltung (inkl. externer Spannungsquelle) verschalten und so an das Modul anschließen?

Unstable PWM from DI/O pins from sbrio 9636

SkuxxDeluxxe — Fri, 03 May 2013 22:54:49 GMT

Hey guys

Im trying to control a Vex Motor Using a PWM generator VI in the FPGA of the sbrio 9636, and I output this signal to Pin 5 of the Digital I/O Pin. Our PWM parameters are 5% duty cycle with a frequency of 50Hz. The output of the PWM is very clean, but its very unstable as the duty cycle changes substantially and the signal itself flickers on and off when measured through an oscilloscope. I've used this signal to drive a vex motor but the motor does not drive well at all. I know its not the motor controller and the motor itself as I have inputted a pwm signal from a waveform generator with the same parameters and the motor runs smoothly. Is there a way to make the PWM output from the sbrio more stable ?

Thanks

compatibility with Keithly PCI-3160

Tim_G — Fri, 03 May 2013 17:50:51 GMT

I need to replicate a test station that uses the now obsolete Keithly KPCI-3160.

I will be replacing it with a NI PCIe-6509.

Will this be a major re-write or minor tweek to the software?

The software was developed using National Instruments Lab Windows CVI.