Using Counters with NI - cDAQ 9172

Hi,
I used to originally run a program with NI 6009 and used counters in LabView to measure vehicle velocity. I had 0-5 magnetic sensor connected to the PFIO terminal. I was essentially counting a falling edge and it worked fine in the NI 6009 module. But when I switched over to the NI 9206 (Fuel Cell) module having the same speed connected to the PFIO termainal I had problems using the counters. Does anybody have any suggestions as to how counters are to be used in the new cDAQ chassis. I found an article in the forums on how to go about selecting internal channels to show up the counters. But even after being able to select one I had no response on the program. Any ideas on waht could be tried to make the counters work?
I have also attached my program if that helps.
Thanks!
Attachments:
Eride_Main.vi ‏108 KB

Hi Rahul,
I want to correct my previous statement. I believe that the following example will show you how to perform a counter task with the 9205.
Regards,
Jim Schwartz

Similar Messages

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

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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Travaux Pratiques d'initiation à LabVIEW et à la mesure
Du 2 au 23 octobre, partout en France

Strain measurement using 9237 and cDAQ 9172

I am trying to measure strain using a 9237 and cDAQ 9172.
The strain gage is connected to 9945 (Red wire to EX+, White to IN+ and Black to QTR terminal also tried connected the white and black to IN+ terminal).
The 9945 is connected to 9237 quarter bridge strain measurement module on a cDAQ 9172. I have two 9237 on the cDAQ 9172.
The device passes the test in MAX.
The problem is I cannot read the strain value.
Can anyone help me please?
Attachments:
Strain measure.vi ‏19 KB

Hi jujare,
In the VI you attached, you don't have the bridge configuration set up. The default is full bridge I, so if you have a quarter or half bridge wired up, that is one reason you could be getting bad data. I'd suggest you take a look at "Cont Acq Strain Samples(With Calibration)-NI 9237.VI" in the Example Finder. It shows the configuration for bridge type and has some handy wiring diagrams. You could also add controls to your vi to set the bridge configuration if you'd prefer.
If your strain gauge only has three wires, it's probably a half or quarter bridge. A full bridge needs at least four wires.
I hope this helps!
Regards,

Physical Connections to use 4 counters with NI 9411 in cDAQ 9178 chassis

Hello,
Currently I have a NI 9411 module in a cDAQ 9178 chassis. I am using 2 of the counters to read frequency measurements.
From the NI 9411 pinout diagram (see pdf file attached to this post), these are the connections I made:
CTR 0 SRC, pin 1 to COM/ground
CTR 0 GATE, pin 2 to first frequency signal
CTR 1 SRC, pin 6 to COM/ground
CTR 1 GATE, pin 7 to second frequency signal
The problem is now I'd like to use the 3rd and 4th counters in my cDAQ 9178 chassis, but I am confused how to wire
in the 3rd and 4th frequency signals, because CTR2 GATE is pin 1 and CTR3 GATE is pin 6. Can I change the pin assignments
to use the other pins in the NI 9411 module for counter frequency measurements? I haven't figured out how to do that in MAX
configuration.
Thanks,
Anna
Solved!
Go to Solution.
Attachments:
NI 9411 pinout.pdf ‏72 KB

Hi EETDer,
The "C Series Signal Connections for Counters" help that you found is a good resource. One thing I want to point out is that for a frequency measurement on a single counter, you only need to wire the signal source to the CTR Gate. Internally, the module will route an appropriate internal timebase to the counters source, therefore you DO NOT want to connect the CTR Source to ground. On your device, you will just wire each signal into the counter source, thereby only utilizting pins 1,6,3,8 for your 4 frequency measurements.
Chris
National Instruments
Applications Engineer

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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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.

How do I acquire multiple signals in the NI cDAQ 9172 using 2 analog input modules?

Hi everyone,
Is anyone familiar with using the NI cDAQ 9172? This is my first time using it and I am not sure what exactly I am doing wrong... Alone with a NI 9233 analog input module, it works great. I can grab my 4 signals from each channel and go. However, when I add another analog input module to the mix, it gets an error. It looks like it is reading only one and not the other. It bombs at one of the DAQ start task and read task.
Basically, the block diagram is just a double of the one 9233 working alone. Is there something needed for input to make the 9172 working? Any ideas?
Any help is much appreciated. Thanks!!

Hi Jud,
Both threads are correct. The cDAQ-9172 has a single analog input timing engine, so both of your analog input modules will need to be in a single task. The other VI you referenced shows one analog input task (with channels added from two modules) as well as an analog output task. Analog output has a separate timing engine from analog input, so both of those can run in parallel independent tasks.
The beginning of this thread is a good example; a single DAQmx Create Task followed by a DAQmx Create Virtual Channel for channels from each module. Also, Getting Started with NI-DAQmx will give you the fundamentals for data acquisition, though I don't know how many of their examples use CompactDAQ.
Regards,
Kyle

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

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

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

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

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

Sample rate for digital sampling (cDAQ-9172 & NI 9401)

Hi!
I have a cDAQ-9172 with a NI 9401 C-series module (digital). I would like to sample the digital inputs with a sample rate of e.g. 400 kHz or 200 kHz. My problem is that I can only select a the 100kHzTimebase clock, and therefore only get a 100 kHz sample rate. The 20MHzTimebase clock is too fast, since it gives me a sample rate of 20 MHz). Is it possible to get a user defined sample rate of e.g. 200 kHz, by e.g. dividing down the 20MHzTimebase clock?
Solved!
Go to Solution.

The cDAQ-9172 chassis does not have an internal timing engine for digital input however you can use one of the onboard counters to generate your clock. Set your pulse train generation counter to be one of the internal counters, such as "cDAQ1/_ctr0" and your digital input sample clock source to be /cDAQ1/Ctr0InternalOutput".

Using Counters with NI - cDAQ 9172

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