PXI-6229 counter output

Hi,
I was using the DAQMx test panel for PXI-6229 module with my PXI-6229 card. I couldn't find an option of routing the counter pulse generation output to different PFIs. It is locked at PFI12 for ctr0 and PFI13 to ctr1. Is there some way by which I can route to other PFIs in the test panel or do I have to write code for it.
I want to route ctr0 output to PFI10 and route PFI12 as a counter input to measure frequency.
Please let me know
Thanks
Shiladitya

Shiladitya,
The Test panels are designed for functional testing only, and do not necessarily expose all capabilities of the device. In order to route these signals to custom PFI lines, you would need to write code. In LabVIEW, this would be done using a DAQmx Channel Property Node. Simply wire the intended terminal to the CO.Pulse.Term property.
Hope this helps,
Ryan Verret
Product Marketing Engineer
Signal Generators
National Instruments

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Changing the PXI-6624 Counter Output rate on the fly

I'm programming an application in VB.net 2005 to set several counter output channels (each with its own task) on the PXI-6624 card. I'd like to know if there is a way to change the frequency of the output without stopping the task, changing the frequency and restarting the task. I'm using the PXI-6624 card to simulate encoders and speed sensors.
Thank you very much,
JonS101

Hi,
Yes, you can change the frequency on the fly. Here is a knowledgebase that will give you an insight of how you should approach this matter. How Can I Change the Duty Cycle on My Continuous Pulse Train? To find this property node and how to use it refer to the DAQmx .NET reference: Where Can I Find NI-DAQmx Property Node Listings and Help?
I hope it helps
Jaime Hoffiz
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Product Expert
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6229 counter output inhibit

Greetings all,
I am trying to use my pci-6229 board and BNC-2090a for the following purpose.
I want to monitor analog votages on AI0-x while putting out a ttl signal at lets say 60Hz.
If an analog signal goes above a certian value I want to stop the counter ttl trigger, or possible
lower the rate, to maybe 10Hz.
The main concern is monitoring the voltages at the fastest update rate and being able to immediately turn off the
outgoing counter or change its rate. By changing the "# of Samples per Channel" the update rate seems to change, but I'm not sure
how to optimize this.
Any suggestions, I've searched the boards but am having some difficulties.
Thanks,
Jim
Message Edited by xband on 01-29-2008 03:26 PM
Attachments:
ReadBNC-2090a1.vi ‏26 KB

Ok, I have made an attempt at doing what I would like using a Pause Trigger, I can make my digital state go to high by putting >1V on AI0.
The counter rate does not change though.
I'm also not sure of how to "Clear" the counter task, whenever I wire to a "Clear Task" outside the loop, it gives an error.
Jim
Message Edited by xband on 01-29-2008 07:56 PM
Attachments:
ReadBNC-2090a Pause Trigger1.vi ‏52 KB

PXI 6229 pulse period measurement

Hi there,
I try to make pulse period measurement using PXI 6229 counter, I have 0.5Vcc according to DMM and 1.05V peak2peak based on scope. Then, I connected 0.5Vcc (incoming pulses) into SCB68 pin 3 and GND pin 55. I used the DAQ assistant to perform measurement n the setting for Signal Input range is min= 1ms and max = 23ms, those values I got it from scope i.e pulse period. I set it to the Rising and Acquisition Mode to 1 sample(on demand). But, I can’t get the measured values and I have no ideal why?
Please help
Walter.

Hi Walter,
the counter input of the PXI-6229 accepts standard TTL digital signals. You can find its specifications on page 7 of this document.
I will repeat the relevant parts here:
Input high voltage: Min: 2.2 V; Max: 5.25 V
Input low voltage: Min: 0 V; Max: 0.8 V
If I'm correct, your signal does not meet these specifications, so in this case you will have to connect the signal to an analog input and measure the pulse width as if it was an analog signal.
Please check this page for an example.
Daniel

Counter Output/Counter Input PXI Signals Behaving Erratically

Question for all your LabVIEW guru's out there,
I am running a frequency loopback test using the NI PXI 6229 MIO DAQ card. I am generating a "Counter Output" pulse train signal which feeds through my device under test and then back out of my device under test and back into the PXI 6229 for a "Counter Input" frequency measurement. Both the "Counter Output" and the "Counter Input" are assigned different PFI lines using DAQmx in LabVIEW.
I have 4 lines to test on my DUT. All four lines run this same frequency measurement but with different PFI lines on the PXI 6229. Each line is test independently.
This is my setup for the 4 lines:
Path 1: P2.0 (Counter Output - Pulse Train) -> DUT (Device Under Test) -> P2.1 (Counter Input - Frequency Measurement)
Path 2: P2.2 (Counter Output - Pulse Train) -> DUT (Device Under Test) -> P2.3 (Counter Input - Frequency Measurement)
Path 3: P2.4 (Counter Output - Pulse Train) -> DUT (Device Under Test) -> P2.5 (Counter Input - Frequency Measurement)
Path 4: P2.6 (Counter Output - Pulse Train) -> DUT (Device Under Test) -> P2.7 (Counter Input - Frequency Measurement)
where:
P2.0 = PFI8
P2.1 = PFI9
P2.2 = PFI10
P2.3 = PFI11
P2.4 = PFI12
P2.5 = PFI13
P2.6 = PFI14
P2.7 = PFI15
I have a LabVIEW VI which generates the "Counter Output" and reads the "Counter Input" frequency. I am seeing weird behavior from the PXI 6229 card. I can test "Path 1" and "Path 2" and the frequency I read is what I generated. No issue there. However, when I test "Path 3" and "Path 4" the frequency measurement is erratic. The readings are two different frequencies repeated over and over again and none of those frequencies are the expected frequency which was generated out of the "Counter Output." If I reset the card, and start by testing "Path 3" and "Path 4" the frequency readings are correct and the erratic behavior is gone. However, when I try to then test "Path 2" and "Path 1" now those lines have the erratic frequency issue. I can continue resetting the card and see same issue. The PFI lines that I test first will always pass.
To summarize:
Steps Taken:
1. Test Path 1 = SUCCESS
2. Test Path 2 = SUCCESS
3. Test Path 3 = Erratic Frequency (Two Frequencies repeated over and over again in my frequency results array)
4. Test Path 4 = Erratic Frequency (Two Frequencies repeated over and over again in my frequency results array)
5. Reset the PXI 6229 Card
6. Test Path 3 = SUCCESS
7. Test Path 4 = SUCCESS
8. Test Path 3 = Erratic Frequency (Two Frequencies repeated over and over again in my frequency results array)
9. Test Path 4 = Erratic Frequency (Two Frequencies repeated over and over again in my frequency results array)
I am wondering if Port 2 (P2.0-P2.7) on the 6229 card has certain dependecies and this is why I am seeing issues. I am trying to get around this issue so that I don't have to always reset the card.
Are P2.0-P2.3 (PFI8-PFI11) and P2.4-P2.7 (PFI12-PFI15) treated differently or require different setup? How do I resolve this issue?
Thanks so much!

I have a theory...
The DAQ card follows a policy called "lazy uncommit" wherein the terminal used for the output will continue to be connected to the counter even after the task has completed (until the terminal is needed for something else). So as you run more tests, the counter output will end up driving more lines. This behavior should be easy enough to confirm.
As the DAQ card drives more lines, I'd imagine this affects the actual signal. You could scope it to check, but it sounds like either the rise/fall times are becoming longer or some extra noise is being introduced on the line.
The readings are two different frequencies repeated over and over again and none of those frequencies are the expected frequency which was generated out of the "Counter Output."
This implies you are picking up an extra edge during transitions--this isn't too uncommon if the signal is noisy since there is no built-in hysteresis on the DAQ card. I would expect the measured frequencies to have periods that sum to either the full period or the semi-period of your actual signal (depending on how many duplicate edges are detected).
Suggestions are as follows:
To stop the DAQ card from driving multiple PFI lines, it would probably be easiest to just programmatically reset the device in between your tests (using DAQmx Reset Device). If you can't reset the device (e.g. because you are running some other task that can't be interrupted) then you can instead configure a dummy task that uses the PFI line in question as an input.
To stop the DAQ card from picking up multiple edges during transitions, you should configure a digital filter on the input terminals. If you reset the device it sounds like this might not be necessary... it's up to you if you want to configure this or not.
Best Regards,
John Passiak

Counter output PCI 6229

Hi all,
i have a little problem with NI pci 6229. I want generate a pulse train on both counter CTR 0 and CTR 1. I look the example that run on machine but i dont find the pin , with the oscilloscope, with y train pulse. I check the between Dgnd and PFI 8 ( pin2 ) but i dont see a train.
How can i solve ? What is the correct pin couter out on NI PCI 6229 ? it is referred to Dgnd?
tanks

Hi,
the terminal for a counter output task is PFI12 and not PFI8. The PFI 12 has the default Pin number 2.
NI PCI/PXI-6229
http://zone.ni.com/reference/en-XX/help/370466W-01/device_pinouts/6229_pinout/
Have a nice day.
Regards,
A.

Counter Output Pin on PCI-6229

I am using NI-DAQmx 7.3 C API with (among others) a PCI-6229.
I have used DAQmxSetCOPulseTerm() to connect a counter output to a terminal other than the default. It seems to work- the output pulses do, in fact, appear at PFI 6 (the terminal I'm using for testing). But the pulses continue to appear at the default output pin as well.
Is that expected?
In order to reverse the situation, I used DAQmxResetCOPulseTerm() just before calling DAQmxClearTask(). The function returns zero, but if I subsequently make a new task to do pulse output from the same counter, pulses appear at both PFI 6 and at the default pin.
Am I missing something?
John Weeks
WaveMetrics, Inc.
Phone (503) 620-3001
Fax (503) 620-6754
www.wavemetrics.com

Salvador Santolucito wrote:
Hi John,
I would suggest using the DAQmxTristateOutputTerminal. I have tried what you are doing in LabVIEW and I'm seeing the exact same results. When I set the default pin to tristate, the counter output does not show up on it.
-Sal
Thanks for trying it and confirming what I saw, and thanks for the pointer to DAQmxTristateOutputTerminal.
John Weeks
WaveMetrics, Inc.
Phone (503) 620-3001
Fax (503) 620-6754
www.wavemetrics.com

NI PXI 6229 DAQ Card Digital Output High/Low Levels

Hi everyone, I can't seem to find in the NI PXI 6229 DAQ spec what the Digital Output high voltage and low voltage is when I set a digital signal high and low. What is the voltage when I set a Digital Output "HIGH" and what is the voltage when I set a Digital Output "LOW"?
Thanks!

See the digital I/O characteristics section of the specs. Typical ttl levels.

How to route the ctr0 in DAQ MX for PXI 6229?

Hello,
The counter ctr0 of the PXI 6229 is internally wired to PFI12.
How could i change the terminal on which this counter is wired? What is the function in LabWindows CVI 7.1 (NI_DAQ MX 7.3) should be used? Is there any example of this? (in all the CVI example the fact that we have to connect the counter to a terminal is just mentioned)
Thanks for your help!
guyom

You can change the output terminal on M Series devices using the following function:
int32 __CFUNC DAQmxSetCOPulseTerm(TaskHandle taskHandle, const char channel[], const char *data);
On M Series devices you can route the output of a counter to any PFI line.
I hope this helps!
gus....

How to Immediately Change Counter Output Rate?

I have a piece of code that largely works like this example: http://zone.ni.com/devzone/cda/epd/p/id/5493
In other words, I set up the Counter Output with some initial frequency and duty cycle, but then during the main loop of my program I continuously change the frequency to a new value based on other criteria.
I'm using an M-series PXI card and LabVIEW RT.
The problem I'm having is that the card waits for the next edge before changing the counter output rate. For instance, lets say it is going at a low frequency and I am upping to a high frequency. If the command arrives in the middle of the current pulse, it will wait to complete the low-rate pulse before starting the high frequency output. Is there a way to make it interrupt the current count and immediately start counting at the new rate?
Thanks,
Isaac

Hi Isaac,
I posted the code in LV 8.2 so you should be able to open it now (it sometimes takes several minutes to upload).
There are a few limitations to using the digital lines instead of the counters:
1. The digital lines are updated off of a sample clock which will be much slower than a timebase. For example, on the 6221 the maximum update rate is 1 MHz, while the counter output has a max timebase of 80 MHz. As a result, the number of frequencies you can generate are going to be more restricted (divide down from 1 MHz vs. 80 MHz).
2. On M series devices, the digital lines must be clocked from an external source. This could be generated from a counter
3. You have to build the digital waveform, which is a bit tricky (I think the example code should help out with that but I haven't had time to thoroughly test it).
4. If you are generating digital lines at fast rates, you will need to write quite a few samples at a time to the output buffer to ensure the data does not underflow. If the buffer includes multiple periods of the digital signal, you would have the case that using the counter output would still update more immediately.
Again, to determine the best course of action it would be useful to know what frequencies you want to generate and which exact hardware you are using. I just mentioned the digital lines as an alternative to the counters, but it might not be ideal for your situation.
-John
John Passiak

RPM Measurement using Quadrature Encoder and PXI 6602 counter

Hi,
I am on a project at work where I need to verify the speed (in RPM) of an unloaded motor which can operate up to 1400 rpm. After doing some research, i determined that a quadrature encoder could be used to make the measurement. I am looking at this encoder http://sine.ni.com/nips/cds/view/p/lang/en/nid/205321.
I have a PXI 6602 counter/timer module in which I would like to interface to the quadrature encoder. I would like to create a VI that allows me to calculate the speed using the encoder. Can someone provide me with details of what needs to be in the VI or an example which can do this? At the most basic level, i want to calculate the speed on demand. After doing this, i would like to figure out how to quickly calculate the speed so that i can determine response time of the speed changing within sub-millisecond resolution (1 ms resolution max).
Further, i created a VI that allows me to change the pulse width of a 100 Hz pulse train at run-time which tells the motor controller the desired speed. I would like to be able to use this VI to change the speed of the motor and the first VI (that I am seeking help about) to calculate the response time (time between the initial speed and settling at the new setpoint).
I am familiar with the NI example finder, but have not been able to find an example that I can use.
Thanks,
Gary

Hey Gary,
I think for you setup, you should try using the Meas Dig Frequency - Low Freq 1 ctr. You can find it by searching example finder with 'low freq'. This vi tells you the frequency of a digital signal by sampling between two pulses and inverting the time between pulses. If you hook up your encoder to a counter and have that counter specified in the vi, it will be able to give you on demand readings of frequency (you can do some multiplication to get the rpm value, freq*60/pulses per revolution of encoder). A simple way to take continuous readings is to put a while loop around the daqmx read and the data output of the read. You can also replace the numeric indicator to a waveform chart to graphically display the change of frequency or rpm readings over time.
You should be able to integrate this as two separate tasks with the pulse train vi you created earlier.
Hope this helps
Luke W

Two counter outputs with 90deg phaseshift

Hi,
I have NI PXI-1042 chassis and two NI PXI-6513 digital output cards in it.
Task is to create two pulses with 90degrees phaseshift.
Is there function in labview 7.1 which generates pulses descriped above. I`m meaning that if I tell function to count up, signal A is ahead signal B and if A is 90 degrees behind B it means counting down?
Is there way to do this by connecting 3 (signal A, signal B and GND) counter wires all in one counter and controlling only one counter to "count output down" or "Count output up"?
- Santtu

Hi Santtu,
I think I understand what you are trying to do.
Essentially you have two counters, but you want to be able to control their
phase relationship to one another. This is definitely possible to do;
however, there are not many examples dealing with it.
I did find one Traditional DAQ Example (non- M-Series) that
might help you out with this: Twin
Pulse Train Generation with Variable Phase Shift Control
Traditional DAQ uses an older API, so I would recommend you look at the
attached example over this example. Just wanted to give you more
than one option.
As far as it 'counting' up or down, that really would have
to be done by a counter input task. Since the input would be the same as
that for a quadrature encoder, then you would use the methods described in my
previous post. As the output it will simply look like two different
counters.
For the best solution though, I went ahead and created an
example for you. It shows how to generate 2 different counter pulses that
are out of phase with one another by a specified amount of time.
Hope this helps,
Otis
Training and Certification
Product Support Engineer
National Instruments
Attachments:
Gen Dig Pulse Train-Continuous-Dig Start-Phase Shift.vi ‏82 KB

Pxi-6229

Hi,
I am using the PXI-6229 DAQ card Part Number 779115-01, for my project. Is it possible to
configure the IO lines as Open Drain/Collector or Push pull? If so, how and which are the
ports we can configure.
Thanks
Shiladitya

Hi Shiladitiya-
All M Series cards operate as 5V push-pull digital outputs and are not configurable for open drain/collector.
Hopefully this helps-
Message Edited by Tom W [DE] on 06-23-2006 09:49 AM
Tom W
National Instruments

PXI 6229 + LabVIEW

Hi all,
I am doing some tests with LabVIEW and I want to send analogic voltage signal to a PXI 6229 (the chassis is a PXIe-1071). I would like to know if I need to add, in the testing programs I have, any control to make the connection between Labview and the controler. For instance, to describe to which connector in the PXI 6229 the cable is connected to (it only has Connector 0 and 1)
Thanks in advance,
Francisco

Hi again.
Thanks everyone for the solutions given. Everything was correctly made, but I was connecting the wrong cable.
I just would like to know another thing: I need to generate a signal using formula block (2 different ones: one with respect to the X axis and the other one with respect to the Y axis). My question is: should I create 2 DAQ Assistants, each one with a different output connected to a different axis, or is there any assembly block that allows me to assemble both formulas block and the connect it (the assemble block) to the "data" part of the DAQ assistant?
Best wishes,
Francisco

PXI-6229 single pulse

Hi,
I am using the PXI-6229. I would like to output a single digital pulse for a specific amount of time. How would I do this?
Thanks

Hi,
There is an example program called Gen Dig Pulse.vi. You can find it in the NI Example finder. Open LabVIEW and go to Help. Select Find Examples. In the Browse tab select Hardware Input and Output>>DAQmx>>Generating Digital Pulses>>Gen Dig Pulse.vi.
I hope this helps.
Regards,
Ima
Applications Engineer
National Instruments
LabVIEW Introduction Course - Six Hours
Getting Started with NI-DAQmx

PXI-6229 counter output

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