External trigger with cDAQ-9172

Hi,
I would like to synchronize my data collection between my EMG system (Delsys Myomonitor) and my VI in LabVIEW. I have a trigger module (Delsys) and would like to use it to start my data collection in both systems. I have a NI cDAQ-9172. Is there any ways I could start the data acquisition in LabVIEW?
Thanks

Which modules are you using in your 9172?
Any DI module with 8 lines or less can be used to route trigger signals if placed in slots 5 or 6 (e.g. 9401 or 9402). Alternatively, if you are using a 9205 or 9206 you may use the PFI to route the trigger signal from any slot in the 9172.
Which modules are you trying to synchroinze? The 24-bit C Series modules use Delta-Sigma converters which have special synchronization considerations.
Best Regards,
John Passiak

Similar Messages

How syncronize PCI4472 with cDAQ-9172?

I need syncronize the acquisition of 32 channels from PCI-4472(8 channels) and rack cDAQ-9172(16ch-9233(4modules) + 8ch-9234(2modules)). I tried several arranges but dont get to do work. I have a 9263 auxiliar module if necessary.
Can anyone help me? A second problem when i do the aquisiton without syncronize is get waveforms with differents DTs between devices.
VI in attached. Thx.
Leonardo de S. Cavadas
Maintenance Engineer and Inspection - Bureau Veritas do Brasil
Engineer Metallurgist with emphasis in Advanced Materials
Technologist in Computer Science
Attachments:
ProdCons2Devices.vi ‏61 KB
CH23DT117.PNG ‏46 KB
CH24DT125.PNG ‏46 KB

Hi Leonardo,
to use trigger from cDAQ-9172, you need an additional hardware-timed digital module to access the PFI lines. The hardware-timed digital module must be installed in slot 5 or 6 to access the PFI lines.
Thus, you can use PFI line from PCI-4472 to synchronize your measurements.
I hope I help you.
Regards,
Ricardo Ramos
Engenheiro de Vendas - Sul
National Instruments Brasil

9472 Error 50808 with cDAQ-9172

I am using the module NI-9472 (digital output) to switch a din-rail Relay with 24V DC that is switching a 3phase contactor, but am I getting the error 50808 when using this module with the cDAQ-9172 on slot 1.
I have tryed the same application, with the same 9472 module with cDAQ-9171 and everything is working ok. The problem only pressists with the cDAQ-9172 and only when I connect the cables from the 9472 module to the relays. If these cables are disconected, I never get the error, and the module LEDs work just fine.
I am also posting the VI I am using in order to get some help, maybe I should do this in other way.
Thank you for the help.
Attachments:
error.jpg ‏92 KB
Test 2.vi ‏50 KB

Hello,
DAQmx returns these errors after the host PC's USB controller reports a USB transaction error.
To recover from this state, you may use this : Programmatically Reset USB DAQ device in LabVIEW
The underlying issue could come from the host controller, the device, or even the USB cable. Some host controllers are more susceptible than others to encountering these transaction errors. It is recommended to double-check your USB cable and if necessary try the device on a different host controller.
You could try a different USB host controller (PCI USB host controllers cost typically between 20 and 30 dollars).
You'll find all these information in the following document : Why Do I Receive Error -50405 or Error -50808 Using an NI USB DAQ Device When Inserting or Removing ...
FYI, a customer who met the same issue get the 9172 working by using an externally powered USB hub.
Regards
Jérémy C.
National Instruments France
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Simultanous multirate-AI with cDAQ-9172 / LV

Hi, we are using the cDAQ 9172 device with two
9233 and two 9215 modules. Is it possible to use these 4(2) modules
with different AI rates at the same time - within one VI?
f.ex.: 2 x 9233 at 50k and 1 x 9215 at 1k
Following the 9172 User Guide there is only one Ai timing engine .... so there is no possibility to do so?
The 9215 runs at a max. rate of 100k - if i use it in cooperation with the 9233 module(max. rate 50k) - the max. "system" rate is then 50k??
Thank you!
bob

Hello,
please have a look at this link:
http://zone.ni.com/devzone/conceptd.nsf/webmain/51f073af23f61a198625710e0076bb24#1
There are different ways to determine the maximum sampling rate.
- DAQmx
- Web based cDAQ advisor
- Lookup tables
The maximum rate for your modules would be 50 kS/s
Best regards
D. Ackermann
Applications Engineer
National Instruments Germany

Counter issues with cDAQ-9172 and 9401

I'm trying to do a pulse count with a 9401 module in a cDAQ-9172 system. My problem is that the count always ends up in the 30 kHz range, when it should be in the range of 1 kHz - 5 kHz. Furthermore, the pulse count doesn't change even when the input pulse frequency is changing. I've used a multimeter to verify that the input signal is pulsing at the expected frequency. It seems like the system is counting the wrong thing (maybe defaulting to some sort of internal timing device?), but I can't figure out what it is or how to fix it.
Any advice would be much appreciated.

Thanks for the response. MAX basically confirms what I've been finding.
Some more specifics:
I have two counters set up, only one of which should be getting a signal at a time. When I connect a function generator sending a square wave to one of the counters, that counter reads the correct frequency and the other counter reads zero - exactly what should happen. When I connect the signal I'm trying to measure to an oscilloscope, it shows a square wave with the frequency I'm expecting. However, when I connect the signal to one of the counters, that counter reads the wrong frequency, and the other counter is counting pulses when it shouldn't be receiving anything at all. The only thing I can think of at this point is that somehow my signal is creating some kind of noise that causes incorrect measurements on both counters, but this doesn't make a whole lot of sense to me, as the oscilloscope shows a pretty solid square wave. In fact, the signal doesn't really look appreciably worse than the output of the function generator. Even if there were some noise, it would have to be pretty severe to affect the edge count, I believe.
Essentially, I've been able to convince myself that the incoming signal signal is an acceptable square wave with the expected frequency, and that the DAQ system is capable of counting pulses on a similar square wave when it comes from a function generator. Somehow, when I try to combine the two it doesn't work, so I'm at a loss at this point.

Strain Gauge Bolts With cDAQ-9172

Hello Everyone,
I am using the cDAQ-9172 with NI 9237 connected to NI 9949. I have some strain bolts that have a value of 2000u for 15.7 kN. I was wondering what I should put in for gage factor? Also what is an appropriate signal input range? Thanks in advance for any help.
James

James,
Those values depend on your particular strain gauge you're using. There should be a spec sheet for your particular gauge that will contain that info.
Kyle Hartley
RIO Product Support Engineer
National Instruments

PFI Trigger with cDAQ-9178

I am trying to receive a trigger input with the PFI on a cDAQ-9178. Neither of the two PFI inputs show up as input options in any of the NI-DAQmx vi's in LabVIEW. How do I get the PFI inputs to show up?
Thanks,
Mike

If you use the DAQmx Start Trigger VI it will be listed in the trigger source input pulldown. See attached image.
www.movimed.com - Custom Imaging Solutions
Attachments:
cDAQ 9178 PFI Lines.png ‏10 KB

NI cDAQ 9172 with 3 USB 9233 for collecting impact hammer data

Hello,
I am collecting data on a NI cDAQ 9172 with 3 USB 9233 cRIO. The software I am using is Sound and Vibration assistant. I have setup the necessary parameters and trigger. The impact hammer is connected on the USB 9233 module one and the rest of the channels on the first module and remaining two modules are accelerometer channels. Would I have a problem triggering the rest of the channels on module 2 and 3?
I have attached my project file for you to have a look at. Thank you very much for your help.
Attachments:
Xrx-run1_11-19-try1.seproj ‏239 KB

The data acquisition part of the project should have just one step. All the channels should be in the daq step of the project. In this way they are all sampled simultaneously and all channels will be triggered and sampled at the same time. This looks like you have this in your project.
I would consider using the cDAQ chassis as the holder of the 9233 which you have. In your project you have all the 9233's in the cDAQ chassis - this is also good.
Since your DAQ step has all the channels, the trigger applies to all the channels in the DAQ step. consider putting a time series plot on your view so that you can see all the data after the trigger. In other words drag the triggered data from the trigger step out onto a graph.
You can also review the the example which ships with the assistant for impact test. Pull down the help menu, select open example, select sound and vibration assistant, and then select the SVA_Impact Test example project.
Preston Johnson
Principal Sales Engineer
Condition Monitoring Systems
Vibration Analyst III - www.vibinst.org, www.mobiusinstitute.com
National Instruments
[email protected]
www.ni.com/mcm
www.ni.com/soundandvibration
www.ni.com/biganalogdata
512-683-5444

Pulse count with a 9401 modules (cDAQ-9172 system)

I'm trying to do a pulse counting by a 9401 module in a cDAQ-9172 system. I have three 9401 modules . One of them is working as a trigger (start-stop count) and the other two (in slot 5 and 6) are for counting pulses from the 2 meters. It looks like a simple task but my problem is that I am counting always 3 to up to15 pulses less than my reference counter. everything points out to a task in my program is causing a delay. The question is where or what is causing such a wrong counting
Attachments:
COOMET Comparison DN80 short.vi ‏737 KB

First for triggering with cdaq you must use the 9405 or 9406 (for analog triggering or 9401 for digital triggering) module in slot 5 and 6 - look in following link. Signals are routed with the chassis PFI Lines and only available at Slot 5 and 6.
http://digital.ni.com/public.nsf/allkb/851828B06A20E01B862571DA0005591A?OpenDocument
http://digital.ni.com/public.nsf/websearch/EFD808DC883F095186257170005A634D?OpenDocument
Then the other moduls in other slots can be configured with these pins for triggering. When you wants triggering on both edges you can look in following link:
http://forums.ni.com/ni/board/message?board.id=170&message.id=248456&requireLogin=False
Best Regards

How to externally trigger the execution of TestStand with a start and abort button through a digital interface?

Hello,
I'm Currently evaluating TestStand as an alternative for an in-house developed Test Sequencer.
To start our own Test Sequencer we use a small box, connected to a DIO board. The box has a start button and an abort button. The box also has a pass, a fail and a running led.
The interface with this box is made via some digital lines of a PCI-DIO-96.
In our own Test Sequencer we have groups named Init, Run, Abort, Exit.
The Init group is executed at startup (only once). It is used to initialize all the HW and SW. -> I guess this is the Pre UUT Loop callback in TestStand.
The Exit group is only executed once at the end of the day when the application is terminated. It is used to free all the used hardware and cleanup all the resources. This probably is the Post UUT Loop Callback in TS.
When a product needs to be tested, the operator presses the "start" button which triggers our own Test Sequencer and the run and abort group are being executed (first the run group, afterwards the abort group).
When the product is being tested the "running led" of the little box lights up to indicate to the operator that the application is running. (only when the run and abort group are running)
The Run group has all the functional tests in it. (MainSequence)
The abort group is used to put everything back in it's original state after the test on this single product is done. (Post UUT)
When executing the tests and something goes wrong (operator gets stuck in a clamper, ...) the operator can still press the abort button and then the execution immediately jumps from the currently executing step in the run group to the first step of the abort group. So, when something goes wrong, immediately the abort group is called.
At the end of the run and abort group, if no errors occured, the "pass led" lights up. If one or more steps went wrong the "fail" led lights up.
This setup can also be used to test multiple product in parallel. At that time all the different parallel testers have such a small box which contains a "start" and "abort" button and a pass, fail and running led. (it is possible that they are all connected to the same PCI-DIO-96 board. )
My question:
Is it possible to do something similar like this in Teststand? If yes, is there an example available that shows me how to do this in TestStand? (externally trigger the execution of TestStand)
Typically, in the Init group (Pre UUT Loop) the digital interface box gets initialised.
In the Close group (Post UUT Loop) the digital interface box is taken out of scope.
Note: The PCI-DIO-96 board to which the digital interface box is connected will also be used in the rest of the developed application (MainSequence, ...)
What's really important for me is that I can create a process model that all the application developers in our organisation can use. I really don't want any of the application developers (limited software experience) to mess around in all the features of TestStand.
For them it's important that they just add the function DigitalInterfaceBoxInit () in the Pre UUT Loop Callback and the DigitalInterfaceBoxClose () in the Post UUT Loop Callback, and then everything works!
It is important that the appliation developers do not have to create any global variables, other functions, synchronisations, parallel sequences, ... in TestStand. All this needs to be done with a simple call to the DigitalInterfaceBoxInit function.
Thanks in advance for all the help!
Best Regards,
Dennis Vanotterdijk
[email protected]

Dennis-
Your application sounds very well suited to TestStand's abilities. I am also quite impressed with your knowledge of how TestStand's architecture is arranged when you are still just considering whether or not to use it.
I think that TestStand would work really well for you in this application. Like you mentioned it will provide you with a form of standardization for your application developers to work from. It also provides the flexibility for you to add your custom routines in many different places. TestStand also makes parallel and batch testing much easier in TS 2.0 so that you could develop one test for your product and execute different instances of it in parallel to test multiple products at once.
As for your specific question about how to c
ontrol TestStand using a DIO board. I think this is very feasible and should not be too difficult. Since TestStand provides you the ability to create a custom operator interface your operator interface could monitor the status of your DIO board and launch/abort executions based on the read values. Usually the executions are launched/aborted when a button on the GUI is pressed however, I do not see any thing different about basing the action on a DI signal vs a mouse click. I am sure your application is more involved than this high level description but from the sounds of it I think it is very possible to do with TestStand.
Based on my experience of building test systems with TestStand and your description of the application, I would feel very confident in using TestStand to achieve all the goals you mentioned. If you have further detailed questions on how one of your features might be implemented, feel free to contact one of our Application Engineers or email us at www.ni.com/ask
and we would be glad to help you.
Best regards,
Richard McDonell
National Instruments

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

Encoder Speed with NI 9215 module and cDAQ-9172

I've a NI cDAQ-9172 with the NI9215 analog input module, and I want to estimate the speed with an optical encoder (OMRON E6A2-CW3C). My approach was, making a comparison with a point in the midle of the high of the signal, ie 4V, making this way a perfect square signal with 1of high. After that I use the Tone Measurements and the Timing and Transition Measurements modules to calculate the frequency of the wave form, and this way I'm able to calculate the RPM speed.
The problem with this solution, is that even with the engine at a constant speed of 746RPM, measured with a stroboscope, Labview give me a high variable values between 730RPM to 760RPM, and I can't solve this problem because I really need an accurate measurement.
Should I buy for example the NI 9401 module to make this measurement? If so, does any one knows how to build a VI to get the encoder speed?
In attach I send the VI that I'm using to calculate the speed.
Thank you for help.
Attachments:
Encoder Speed.vi ‏112 KB

Hi,
The best way to measure a speed through a quadrature encoder is to use the counters that are inside the cDAQ chassis.
With the 9172 chassis, you need a digital I/O module (9401) in order to access the counters.
With the new generation of chassis (9178), you don't need the 9401 because you can connect your encoder signals to the BNC.
Best regards,
Thomas B. | CLAD
National Instruments France
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Labview interfacing with NI cDAQ-9172

I currently have access to a NI cDAQ-9172 with a NI-9205 AI input
board and a NI-9481 relay control board. I basically have the DAQ
Assist tools for the analog inputs and the relay outputs, however, I'm
having trouble interfacing them together, such as if the two analog
outputs are above x Volts, turn on the relay control; otherwise, turn
it off. Do I need to create a task for a specific DAQ Assist tool in
order to control the behaviour of the relay outputs based on the
analog inputs?

Hello Stanley,
Let me try to address your questions in order:
1. LabVIEW gives you the ability to program several design patterns
including Finite State Machine, Master/Slave and Producer Consumer.
LabVIEW even provides templates for these design patterns, which you
can create by going to the File menu and selecting New.... The image below shows where you can select from the different design pattern templates.
For more information about the state machine design pattern specifically, I would recommend that you examine this tutorial.
2. I believe the "DAQmx Tools" you referred to are the DAQmx sub-VIs in
the DAQmx sub-palette. You must use the inputs (controls) and outputs
(indicators) to configure these VIs, there is no pop-up menu like there
is for the DAQ Assistant. However, you are able to generate the sub-VIs
from a configured DAQ assistant using the right-click menu, as shown in
the diagram below. This would allow you to configure your NI-DAQmx operation with the pop-up window, and then optimize performance using the DAQmx sub-VIs.
3. Based on the description of your application, I would strongly
suggest that you consider either the state machine template discussed
above or the NI LabVIEW Statechart Module. This module is designed to
give you a higher level of abstraction for complex systems. Since you
already have a flow chart, it seems that it would be pretty easy to
convert that to a statechart to programmatically implement it. You can
see a video here on how to implement state machines in the LabVIEW Statechart Module.
If you have questions about how to architect your program specifically,
I would recommend that you post to a new forum. You are more likely to
get better insight and more relevant information on that topic if you
post a new question that reflects the appropriate topic.
Message Edited by Matt A on 09-17-2007 07:37 PM
Matt Anderson
Hardware Services Marketing Manager
National Instruments
Attachments:
Generate NI-DAQmx Code.JPG ‏16 KB
Design Patterns.JPG ‏73 KB

Externally trigger hr2000+ spectrometer with dg535 delay generator

Hello all,
I have three Ocean Optics HR2000+ spectrometers, an Ultra 100 laser, and a Stanford Research Systems DG535 delay generator. I'm using the delay generator to trigger the laser, shortly followed by the 3 spectrometers (all 3 simultaneously).
I've managed to get this procedure working in SpectraSuite and tried to replicate it in LabView using the HR2000+ LabView drivers. The spectrometers have individually worked in normal and external trigger mode in LabView, but as soon as I try to fire and sync all 3 spectrometers using the delay generator, LabView staggers their waveform acquisitions to happen one at a time. This defeats the purpose of the delay generator.
I tried using a flat sequence structure to make sure the integration times and triggering modes have executed before the waveform acquisitions begin with no success.
The attachment shows my code before I had a flat sequence frame between the trigger and waveform acquisition functions.
The delay generator has been controlled both manually and through LabView as well. I'm using a Win 7 machine.
Thank you for any help!
Sincerely,
Mike
Attachments:
specs.png ‏71 KB

Hi Daniel,
Attached is the driver I used.
My code looks more like the Acquire Multiple Waveform VI under the Example folder.
Are you suggesting I do something similar to the Acquire Continuous Waveform VI?
Everything works up until the simultaneous part, and it also works one spectrometer at a time.
Thanks!
--Mike
Attachments:
ocean_optics_2000_4000.zip ‏574 KB

[Question] PCI-6220: digital level at the pause of a continuous impuls train with external trigger

Hallo,
I'm trying to use a PCI-6220 card to generate a continuous impuls train which will be paused at an external trigger. I've used the example code in the example library to generate the impuls train. The idle state of the impuls train is set to be high. But I figure that die digital level at the pause is sometimes high and sometimes low. I suppose that the level stays at the exact time when the pause begins?
Is my assumption correct? Is there any way to let the impuls always pause at the idle state, like it will then be paused after a full impuls is finished? Any tips or links will help. Thanks in advance.
Wei

Yes your assumption is right. The output is latched to the last set value.
If you are generating the pulse through the counter, setting the Idle state in Create Virtual Channel.vi doesnt help?

External trigger with cDAQ-9172

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