Synchronization in PCI-6221

Hi. I use the device PCI-6221: 1 analog output and 5 analog inputs. I set the waveform graph for the input signals. I generated the sine signal. The input waveform on the graph changed continually its phase. What have I to do to leave the phase unchangable while changing the amplitude or the frequancy of the output signal?
Thank You.

Hi Dimon87,
Many times on a traditional scope, a waveform is displayed so that the zero crossing is triggered to be at x0. Is this what you are attempting to do? With 5 channels on a multifuction DAQ board, there is an interchannel delay (as you've discovered in other forum threads) between the channels so if you're looking for channel phase relationships, you'll be limited to this delay. It sounds like you're looping your analog output back into your 5 analog outputs so this would definitely have a phase delay between the 5 channels due to the interchannel delay. Your previous thread "Measuring the subtract of two phases" talks about this.
PBear
NI RF

Similar Messages

How to get counter values from pci 6221 card?

Hii
I am using PCI 6221 card .. In that i am using the ctr o .. In my application i am using Linear encoder to measure the Lift movement.. so from software how to access the counter values i.e how much mm it moves...

Measure Angular Position.vi in the LabVIEW examples will be a good starting point. Adapt it to Linear Encoder by clicking on the selector below DAQmx Create Channel.vi.
You can also create a corresponding DAQmx Global Channel (or task) in MAX and then use it in your code.
Feel free to post back if you need further help.
Message Edité par JB le 10-31-2008 02:15 PM

How Do I enable multiple trigger voltages on the PCI-6221 using NI-DAQmx?

I am using the PCI-6221 to do some simple data acquisition. The idea is to allow three different analog voltages to trigger the data acquisition state. I currently have the code set up for one voltage trigger but I am not sure what needs to be done to add the two additional trigger voltages. Any ideas?
Thanks.
Solved!
Go to Solution.

Is it possible to do something as simple as this:
    DAQmxErrChk
        (DAQmxCreateAIVoltageChan(taskHandle,"Dev1/ai0","",DAQmx_Val_Cfg_Default,0.0,5.0,DAQmx_Val_Volts,NULL));
    DAQmxErrChk
        (DAQmxCfgSampClkTiming(taskHandle,"OnboardClock",3000.0,DAQmx_Val_Rising,DAQmx_Val_FiniteSamps,3000));
    DAQmxErrChk
        (DAQmxCfgAnlgEdgeStartTrig(taskHandle,"Dev1/ai0",DAQmx_Val_Rising,0.7));
or will I need to put the trigger on PFI0?

How do i create 6 digital 25Hz PWM output signals with my PCI-6221 card?

Hi!
I´m a student, who´s trynig to control a gasturbine process for my diploma thesis. The control program should be written in LabView 8. I need to control 6 25 Hz PWM signals for the gasvalves. The needed accuracy of the duty cycle has to be about 0.1 %.
A tech. engeneer from NI told us , that we can do this by using one single digital output for each PWM.
Now, after a while, i need to implement it into my program. But there are troubles:
My NI-PCI-6221 standard card only has 2 couteroutputs and only the first of the 3 ports seems to be buffered (Error Nr. 201062)...
I tried to do the programming, by manipulating the "DIO_PWM_50Hz.vi" I found in google.
Does anyone of you have any information or helpful examples how i can create these PWM with my card, or did I get a wrong Information by the salesagent (...not the first time....)?
Thanks for your help
Tobi

Here you can find an example, how to do this:
http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=DE27921DB53A4D8DE034080020E74861&p_...
As the text says, best would be to use the counter. As your Hardware has only 2 Counters, you would need additional hardware. Best would be to use a Counter-Card (660x), thes boards have up to 8 counters, so you coulkd control your 6 gasvalves indipendently.
The soultion with the timed digital outputs of the m-series boards would only work, if you can use the same timing (one counter) for all 6 outputs.
Hope this helps!

Using timer/counter with PCI-6221/USB-6210 to control timed-loop VI

Dear all,
I need to ask about two devices and one of their functionalities, PCI-6221 and USB-6210. For our NI-based system, we need to control some timings in a Timed-Loop vi, for that currently we are using PCI-6221 and we give external TTL signal (at 1 kHz) to it,
recenntly we need to make some changes and for that we found USB 6210 DAQ to be more suitable, but we need to clear ourselves on some specific things.
Can the counter/timers functions available in the either PCI 6221 or USB 6210 can be used to control the Timed-loop VI by giving external clock or by using their own internal clock source?
Although we are using external clock with the PCI 6221 but we want to know about the usage of their internal clock, also are controlling timed-loop also possible for USB-6210
Also... What if we use the RTOS, are they still able to control the timed-loop VI without giving any 'EXTERNAL CLOCK' and using the internal clock sources of the DAQs
Waiting for reply,
Bests,
RaJaf
Solved!
Go to Solution.

Ben,
I having read previous email which I send earlier with general overview, we discussed in more detail within our team and I am giviing the specific answers.
Please check in RED the most recent answers. Blue are the questions/suggestions by your side.
1.    Using Internal hardware clock of PCI-6221 would enable us get rid of external clock, but how to divert the internal hardware clock to the current settings. Any idea (can you provide us with some reference manul for otherwise). I mean is there some flag-bit etc. or VI
2.       Is it also meant that with the installation of RTOS the timed-loop can directly get the timing source from the internal hardware clock PCI-6221? --- How???
3.       In order to make desktop to work as RT system, what is the hardware (motherboard, processor, etc..) requirement? What are the LabVIEW modules (specific name) that needed to be installed? Our platform is LabVIEW 8.6. (Currently we have windows-7 with i7 core processor)
What kind of application are you intending for this system? ---- high-speed laser scanning system.
Are you most concerned about accuracy, speed, or responsiveness? To control the laser mirror scanner to move at 1 kHz or 2 kHz speed. On the other hands, using PCI-5105 (128 MB memory) as a DAQ for real-time/on-the-fly data processing.
Bests,
RAJAF

Im using a pci-6221 daq-card.I want to know the difference(use)of a line output and a port output.

Im using a pci-6221 daq-card.I want to know the difference(use)of a line output and a port output.

Hello Hellraiser24,
This question has actually been discussed in another thread here:
http://forums.ni.com/ni/board/message?board.id=170&message.id=95895&requireLogin=False
I hope this helps,
E.Lee
Eric
DE For Life!

How to entirely develop an application with PCI-6221 in Borland C++ Builder V6 in DAQmx?

Hi,
     I am sorry that I have asked a huge question.
     But the main questions I want to know is :
     1,In Borland C++ Builder 6,Which version of DAQmx is the best one we will use? DAQmx V8 don't support BCB6.
     2,Would you please give an example source file to use *.Lib in BCB6?
     3,In other computer,not including developping environment ,which items of DAQmx we have to install,PCI Card Driver?
Which dll?How to make the installation the smallest?
     Thanks for your possible answer.

Why DAQmx8 doesn't support C++ Builder 6 ?
I've just used LabVIEW with DAQmx8 create dll file for C++ builder 6. My application is to use PCI-6221 generate Analog output. ( just DAQ assistance ).It works well.

How can I configure NI PCI 6221 and DAQ SCB-68 for pressure sensors?

Hello
everybody,
I am using the measuring board (NI PCI 6221) and DAQ
SCB-68 for the data acquisition.
With the DAQ-Assistant I created AI for the voltage of
pressure sensors. In a big indicator panel from this DAQ-Assistant I see the
voltage for both sensors in the correct size. But if I set sensors in the
blockdiagramm to control the signals for sensor one I get a wrong voltage size
and for sensor 2 nothing.
How can I configure this data acquisition equipment to
get the correct signals?
Thanks a lot for your help.

I do not know the type of sensor you are using. But pressure transducers may have a very low output voltage(in the mVolt range). They also need an excitation voltage. Here is an introduction. http://focus.ti.com.cn/cn/lit/an/sloa034/sloa034.pdfThen working with pressure sensors I always use 3 stages in the circuit.
1 Instrumentation Amplifier as a preamp
2 filterstage
3 Final amp and output buffer
(you may combine stage 2 and 3)
Besides which, my opinion is that Express VIs Carthage must be destroyed deleted
(Sorry no Labview "brag list" so far)

PCI-6221 fails self-test in MAX but device manager says it's working

Hi everyone,
I bought a few PCI-6221 (37-pin) data acquisition cards and have been able to get one to work but 3 others don't work.
Device Manager sees them and says they work. MAX sees them and when I run Self Test, they fail with error number
-50002. Motherboards in non-working systems are PC Chips M957G and P25G. OS is Windows XP Pro with SP2.
I already tried uninstalling SW and the board, reinstalling SW and the
board...autodetect etc works fine. I even reformatted
the HD on one of the computers and reinstalled the OS. Anyone have any ideas? Thanks in advance. Halden
[email protected]

Thanks Tom for your suggestion to try NI-DAQ 8.0. I just saw it today. Yesterday,
I was able to isolate 3 PCI-6221-37 boards as defective because they all wouldn't work in another computer while
one other identical model card did work in that same computer. I called to arrange to return them to NI and learned
that for these 3, I needed NI-DAQ 8.0. The fourth one was okay
with NI-DAQ 7.5. Apparently, this was a known problem.
I wish NI would have simply notified me that my boards would
not work with the software sent with them and sent the NIDAQ 8.0 CD as soon as they knew rather than have me
waste a day of my engineering time trying to figure it all out. Booo NI.
One of the boards has worked for almost a day under NIDAQ 8.0. I was able to make some progress on the
system I am building. But then it stopped working. LabVIEW
(version 7.0 executable) programs would not open completely
or would open slowly. One that accessed the COM port only (no
data acquisition) did work. MAX opened very slowly or not at all
and when I click on
Devices and Interfaces, the hourglass is up for a long time and finally the + icon goes away indicating that MAX is not
aware of any devices being present. The Windows Device Manager says the board is present and working. Windows
Task Manager lists LabVIEW Runtime and MAX when only MAX is open and indicates that MAX is Not Responding.
I shut down the computer, removed the PCI-6221 board, booted it up again, and MAX is the same way. I uninstalled
MAX and NI-DAQ LabVIEW 7.0 support and then reinstalled them.
Now the MAX loading window is up for more than a minute and NIMAX.exe is listed in Task Manager's processes. After
the first minute, LabVIEW Runtime appears in the Task Manager's
Applications list. After a while longer, the MAX window finally
opens
and MAX is listed in the Applications. I click on the + icon by Devices and Interfaces in MAX and the hourglass appears
and Windows Task Manager says MAX is Not Responding. Eventually, the + icon and the hourglass go away and
the Task Manager lists LabVIEW Runtime and MAX as Running.
I shut the computer off for several minutes, started it up again, and MAX is still takes a long, long time to open.
I haven't put the PCI-6221 card back in because MAX still isn't working.
What do you suggest I do next?
Thanks
Halden

Trouble specifying TTL for digital outputs from PCI-6221

Hi!
I'm trying to generate TTL output signals using a PCI-6221 daq board - within Labview, I'm using DaqMx to create two digital waveforms and then write these. When I plug in an oscilloscope, the shapes/frequencies of the signals are correct, but the lower value is 0V, and the higher value is 1V, rather than the TTL values. Is there a way to specify these voltage levels to TTL within the software? I see from NI help that "do.logicfamily" exists to specify TLL, but when I add a property node and connect it to the channels, I do not see Logic Family as an option under "digital output." Let me know if you have any ideas!
Thank you,
Emily

Set your oscilloscope to use 1MOhm impedence. Your problem is that the maximum current for those DIO is 24mA. 1V/50 Ohms = 20mA. So you are current limiting the digital outputs. If you need more current, then you need to add in some digital buffer chips that can output more current.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines

How to use scb 68(pci 6221) for voltage and current measurement

hi

PCI 6221 is DAQ card with 68 terminals and SCB (Shielded Connector Board) 68 is termination board to those 68 pins of 6221 card, so that you can connect signals (to be measured) to appropriate pin of PCI 6221. You might already aware of it.
Refer to the pin out of PCI 6221 to check which is the correct terminal, for voltage measurements.
You cannot measure current directly, instead use a resistor of known value (and appropriate current rating), let current (to be measured) flow through it and measure the voltage across that resistor.
I am not allergic to Kudos, in fact I love Kudos.
Make your LabVIEW experience more CONVENIENT.

How to fix error -50010 in MAX 4.0 self-test of PCI-6221-37?

Hello Tom or anyone who could help
This is a continuation of my previously posted problems getting my PCI-6221-37
card to work.
I reformatted the hard disk and reinstalled Windows XP Pro on the computer. Then
I re-installed NIDAQ 8.0 with LabVIEW 7.0, 7.1, and 8.0 support. Now MAX
opens in a reasonable period of time and recognizes the PCI-6221-37 card. When I
run the self-test option, it replies with an error -50010. "The specified offset is out of
range for read operations. The operation could not be completed as specified"
Any ideas?
Halden

Hi Halden-
Let's continue our discussion here. I am in contact with our software engineers to help diagnose this problem. If you could provide a screenshot of the error in the other thread, it would be a huge help. Thanks a lot-
Tom W
National Instruments

How to make a ramp for a stepper on PCI-6221

Hello!
I'm looking for a solution/example in ANSI-C to make a ramp for a stepper that is connect at PCI-6221 CTR-port.
The function I'm actually using is:
DAQmxErrChk (DAQmxCreateCOPulseChanFreq (taskHandle, "Dev2/ctr1", "", DAQmx_Val_Hz, DAQmx_Val_Low, 0.0, 1000.0, 0.5));
DAQmxErrChk (DAQmxCfgImplicitTiming (taskHandle, DAQmx_Val_FiniteSamps ,1800));
So this works fine when the stepper have to run constantly. But for my application I need the use of a ramp. To change the frequency value I have to write in a running Task, but that is (IMHO) not possible? Please correct me, if I'm wrong.
I don't not know how to change the value unless to stop the task and start it with new value. But this method is not a solution, cause i always stop the motor and start it with a higher frequency from zero. So what I'm actually do is to look after the correct NI-function for my problem.
If someone has an idea/example/solution, please post it. I'm thankful for all kinds of feedback.
Best regards,
Oliver

Unfortunately, ramping a stepper is not straightforward using the counter hardware. Under finite generation, the freq cannot be changed on the fly. And under continuous generation, where freq *can* be changed on the fly, it must be done under software-timed control. Also, under continuous generation, it will be pretty tricky to both change the freq on the fly *and* control the exact total # of steps.
If you need a well-controlled ramp and a well-controlled # of steps, I'd suggest you start figuring out a scheme to use the hardware-timed digital output port (see also "correlated dio"). The big downside is that you'll need to generate a large buffer of digital states to define your pulse train because you'll probably need to output at something approaching a MHz. Out of those million samples per second, probably only about 0.1% of them represent transitions.
When these kinds of apps come up, I always put in a good word for one of NI's Alliance partners - Viewpoint Systems, who sells a digital board that works much more sensibly for these situations. With the DIO-64, you create buffers containing only the timestamps of the transitions and the digital state at those transition times. So to generate 1000 steps in a second, you'll buffer 2000 states rather than 1,000,000. You'd also get ~20x better quantization error for your available step rates.
I've been requesting a buffered counter output capability from NI since before Y2K, so I'm no longer holding my breath...
-Kevin P.

High frequency quadrature decoder (NI PCI 6221)

Hello, i would like to ask you about high frequency quadrature decoder. I am using module in DAQmx for measuring linear position. For this i am using NI PCI 6221. My problem is that i want to use this for my interferometer and we need really high speed. So I tried to use External timing whitch should be possible for this card up to 80MHz. Unfortunatelly i always will get error message that there is some kind of owerflow and my program crashes. So my question is how to get all data form this card. I know that the buffer size FIFO is only 2 so if it is impossible to get all data so i want find another solution. Is it possible let my card work alone on 80MHz and only repeatly rewrite all buffer and just sometime ask this card for sending current buffer. I dont really need all the data, but when i will ask i need to know reall position. This high speed is really necessary because my interferometer is sensitive and i dont wat to lose any steps. If there would be any possibility how to work on 80MHz and only sometime ask for sending data with position, it would be great. Sometimes i will ask not for only current position but for full buffer because i want so see what is happening during some time period, but this task will be only sometime.

Dear BMAJTZ,
The counter frequency (the maximum speed available) is configured by the Task in the background. In our case, the counter is set to detect edges, so it always uses the maximum speed available. If an edge occurs, the count value increases by 1, and this accumulated count value (stored as a binary number) is read by the DAQmx Read VI, and converted to meters. So if your encoder input is slow enough for the 80 MHz card to handle, you won't miss any ticks, even if you only read the value occasionally.
You can find further information about counters and encoders on these links:
http://www.ni.com/academic/students/learnlabview/digital.htm
http://www.ni.com/white-paper/7109/en
Also if you can tell me the approximate frequency of your encoder signal, and how often you nedd the position info, I can do some benchmarking for you to see if your card is capable of the task.
Best regards:
Andrew Valko
National Instruments
Andrew Valko
National Instruments Hungary

Error 200141 when trying to measure motor encoder's speed from PCI 6221 card,

Hi,
         I was trying to measure angular speed of a motor from its encoder signal. I'm using Ctr pin from PCI 6221 card take signals from the encoders. The problem comes when I've got an Error-200141 saying "data was overwritten before it could be read". I have tried a few ways as follows to overcome this problem.
     - Use DMA
     - Get rid of the noise from the signal by shielding the wire from encoder to DAQ card and using a capacitor.
        None of those seemed to solve the problem completely. Even though the noise from the signal was removed, I could still see the mechanical glitter at the edge of all the pulses from the oscilloscope. Is that a possible cause of this problem (my technician told me we can do nothing with this glitter. In other words, we can't remove it)?
        Please suggest me how to solve this Error-200141. With this message, I have also attached VI.
        Thank you very much.
   Regards,
   Suksun
Attachments:
Meas Dig Period-Buffered-Continuous-Low Freq 1 Ctr_Angular speed from encoder.vi ‏72 KB

Hi Suksun,
Only had a quick glance at your code, but can you drop the samples to read to 100.
I think what the problem is from what I can make of your code, is that
you have a low frequency counter, that you measure on the rising edge,
however if you don't get a 1000 pulses within 100 seconds, DAQmx will
report an error. So by lowering the number of samples to read you
should be able to get 100 samples in 100 seconds, you should not
overwrite data as the buffer will be sized correctly.
Hope this help
Regards
JamesC
NIUK AE

Synchronization in PCI-6221

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