PXI 6239 counter

Hi,
I have PXI-6239 card , i have many query on this card .Does this card requires any external voltage for counter input and timer output .I am not able to read timer output i have done a code for this everthing is correct eventhough i am not reading any frequency but in the multimeter it shows overloaded but i have given input as just 10 HZ. And also i have dount on digital output i have conneccted the external circuit as shown in the user manual but here also same problem that i am not reading any voltage.Could any one clarify about this

Hello AutoTec,
You do not need to connect an external source to your
counter. There are a few counter examples
that are shipped with LabVIEW and will measure a digital frequency. (Hardware
Input and Output >> DAQmx >> Counter Measurements >> Digital
Frequency >> Meas Dig Frequency-Low Freq 1Ctr.vi) Connect your signal (10Hz signal) to the gate
(Pin 32 or PFI 1) on the counter.
Pin 32 can be used for a PFI line, P0.1 digital input line
or a counter gate line. If you use this
pin for your counter application, you can not use as a PFI or digital line.
Respectfully,
Rob F
Test Engineer
Condition Measurements
National Instruments

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Using PXI 6251 counter to delay a trigger on PXI

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I need to synchronize some devices on an PXI chassis. Basic operation is a user waveform generation on a PXI5401 that routes the Trigger Signal for the generation to one of the PXI (RTSI) lines. I'd like to use this trigger signal to start a counter on a PXI 6251 counting the PXI 10MHz Clock. No problem so far ( at least none that I see What I need is a possibilty to set another sync signal as soon as a certain counter value is reached in order to use this signal as a delayed trigger signal. Is it possible? And how? I've taken a look at the LabVIEW Example finder, but haven't found an example yet...
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Nathan,
Thanks for your excellent solution. I'm ordering the Aux100 cable (9-Pin DIN to two BNC Female) to export the trigger signal from the PXI to the Device_2. I will test the program (Echo_Mode_PXI_5122.vi) to be sure it will be suitable for my application.
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Attachments:
Echo_Mode_PXI_5122.vi ‏49 KB
Pulse_Echo_Mode_PXI_5122.vi ‏49 KB

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

WANTED: NI PXI-6602 counter/timer

I'm looking to buy a used NI PXI-6602 counter/timer board. Got one?

"Zvezdana S." wrote in message
news:[email protected]..
> Hugh,
> To possibly obtain an used board from National Instruments, you should
> contact your regional Internal Sales Representative (ISR) for possible
> used boards. If you are not sure who your ISR is, generate a service
> request at:
I never knew NI had an SRQ line we could pull.
Craig Graham
Physicist/Labview Programmer
Lancaster University, UK

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
National Instruments
Product Expert
Digital Multimeters and LCR Meters

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

PXI-6123 counter connections

Good afternoon.
As a labview novice, I apologize in advance for any poor communication on my part. But, after scouring the discussion boards for a day and a half, I thought it time to post my situation. Thanks in advance for any help/discussion.
Hardware: PXI-6123
The setup:
Coming from an encoder on an electric motor I have 6 wires that carry 3 signals.
1) A and A_not
2) B and B_not
3) Z and Z_not
The potential across A and A_not is a square-wave of +/- 10V who's period ocurrs 1024 times per motor revolution.
The potential across B and B_not is also +/- 10V and it's 90 degrees out of phase with the A signal
The potential across Z and Z_not is at -10V for the majority of the motor's rotation, but sends a +10V square signal briefly once per motor rotation.
(i.e. pretty standard encoder signal)
Problem: I'd like to use the counter to process (RPM, angular position, etc.) these signals, but they are not in a TTL format. The best I can do at the moment uses an external ground as a reference, such that the A signal moves +/- 5V relative to this ground.
The PXI-6123 card specs call for a 0-to-5V signal for its counters, and I'm worried that the -5V will damage the card.
I understand that I could bring in these square waves at analog signals, convert them to digital, and then use the counter to process the digital. Is this the way to go? The sampling rate associated with this conversion would have to be relatively fast in order to resolve the square waves, could this sampling/conversion process work separately from the sampling and recording of the other analog inputs? I am recording 5 other analog inputs while the motor is rotating, and it would be undesirable to have to record these signals as very high rates.
So in summary, the big picture is:
-I have a +/- 5 V encoder signal from which I'd like to record the angular position of a motor.
-recording this angular position, in conjunction with other analog inputs, should not have to occur at very high sampling rates
It seems inputting the encoder signals into a counter is the best option. Expect for 1 snag: I worry the -5V bias will damage the board.
Thanks in advance!
-Mike

Hi Brendel, this is Paul with Applications Engineer at NI.
You are correct that your card only supports 0-5V aka TTL counter inputs. Only our industrial cards support the higher voltages.
There are a couple of ways we recommend to work around this, the first is to use a Schmitt Trigger to bring in your signal, and then convert it to the 0-5V you need.
The second is to use the analog triggering on your card to perform an analog comparison event, that I'll let the following links describe better than I can.
Explanations:
http://digital.ni.com/public.nsf/allkb/771D82A44F27A0AF86256DD0007FB9A1
http://digital.ni.com/public.nsf/allkb/39DF4F9A6F285E7986256B58006FC129
A forum post with a good discussion about it:
http://forums.ni.com/t5/Counter-Timer/Measuring-frequency-of-non-TTL-pulse-train-with-counters-on/m-...
And, some example code to look at:
http://zone.ni.com/devzone/cda/epd/p/id/2555
Let us know if you have any further questions.
Thanks,
Paul
Paul Davidson
Sound and Vibration Software Staff Product Support Engineer
National Instruments

How to access PXI 5152 from a Laptop via ethernet cable?

Hi, I have the following setup.
   PXI 1002 chasis
         PXI 8175 controller
         PXI 6025E DAQ card
         PXI 5152 scope
          PXI 6602 counter timer.
    I have written a program that uses the counter timer for triggering an external circuit board and the scope for data acquisition. I need to run the vi on my laptop and get access to the PXI devices.
I have connected the Laptop to the PXI using a cross over LAN cable and configured manual IP addresses and identical subnet masks on both systems. If i run the Remote Device Access Server(RDA) on the PXI chasis, I can access the 6025E card and a portion of the 6602 card also. I can see them from MAX directly.But how can I access the scope, as the RDA server works only with DAQ devices.
What I want is a method to configure the PXI system as a remote device on my Laptop.so that I can see the PXI cards in NI MAX on my laptop.
I would like to see if I can do this without having to get a new express card.
Please help!! I am newbie with remote systems.
Thanks in advance!!

Hi JJ,
Sorry for the delay. You are correct that using remote
front panels will still require the VI to run on your PXI system, and you will
not be able to do any configuration other than that allowed with the front
panel. If your controller is slow, is there a reason why the development can’t
be done on another computer and then transferred to the PXI system only to
test? To help speed things up on your PXI system, you could create an exe on
your development machine (if you have the application builder or LabVIEW Professional)
and then run this on the PXI system. This only requires the LabVIEW runtime engine
(which is already installed since LabVIEW is on the system), but will not
require LabVIEW to open. If you do this, please read this knowledgebase: How Do I Enable The Web Server Or Use Remote Panels With an
Application (EXE) Built in LabVIEW?
As far as the RT vs. Win 2000 – this can
change things very juristically. If you boot using RT, then this will require
you to develop on your host computer, and then deploy it to the RT system. If
you use Win 2000, then my above comments apply.
Hope this helps you out.
Message Edited by David L. on 06-10-2008 02:37 PM
David L.
Systems Engineering
National Instruments

How can i find out the resolution and accuracy of PXI-6602 module?

I have a 32 bit 8 channel PXI-6602 counter module. PXI card is interfaced to PC with MXI-4 link. How can i find out the resolution and accuracy of this system.What is the maximum accuracy and resolution i will get from this system. Because optical signal to cmos conversion signal is given as a input to the counter.

Hi chandhu,
Were you referring to the accuracy of the count register or the timing clock?
PXI-6602 specifications can be found in the NI 660x Specifications. The resolution of the count register is, as you’ve noted, 32 bits. This corresponds to a maximum count value of 4,294,967,295. As long as all of the edges are in accordance with TTL specifications, the accuracy of the count register is 100%.
On the other hand, the PXI-6602 baseclock accuracy takes on the baseclock accuracy of the PXI CLK 10 signal. Again, this is all found in the specifications.
You may also want to check out the NI 660x User Manual – it contains a lot of details on the operation of these counter/timer devices.
I hope this helps. Please post back if you have further questions.
Ed W.
Applications Engineer
National Instruments

Pulse Generation application with DAQmx and a PXI-6624 module?

What is the best implementation method for the following pulse generation application
using LabVIEW, DAQmx and a PXI-6624 counter\timer module?
I have two rising edge trigger signals (Trigger-1 and Trigger-2).
There is ample spacing between each trigger. They never occur at the same time.
I need to generate a single pulse (fixed width, variable delay) whenever Trigger-1 occurs and
a finite pulse train (fixed width, variable delay, N-pulses) whenever Trigger-2 occurs.
However, the output must appear on one counter output because this composite signal
will be used as a trigger source for another PXI module in the rack.
With DAQmx and a TIO counter\timer can I use both the GATE (for Trigger-1) and
AUX (for Trigger-2) at the same time on the same counter to gate out the desired pulses?
Trigger-1 would be wired to the GATE of CTR0. One Trigger-1 event would generate one pulse on the output of CTR0.
Trigger-2 would be wired to the GATE of CTR1 and the output of CTR1 would be routed to the AUX input of CTR0.
One Trigger-2 event at the GATE of CTR1 would generate multiple pulses on output of CTR0.
Would DAQmx and the PXI-6624 TIO support this implementation?
What is the best way to accomplish the task at hand.
Thank You.
Best Regards,
Scooby

Hi Scooby,
I have looked into the application you have described and I see a potential problem with what you describe. In DAQmx, it is not possible to call the counters of the same DAQ device in the same task, so you cannot have the finite pulse train generation and the single pulse generation tasks running at the same time. What you can do, since you mention the triggers will not occur at the same time, is to stop one counter task while you are triggering another. The way I would suggest you merge the outputs is with a two input Or logic gate to avoid damaging your counters. Your signals will effectively be added together by this logic gate. I do not see any way to merge the outputs internal to the DAQ device.
Please let me know if I can be of additional assistance.
Laura

CTR works with PXI 8196,PXIe 8102, fails with PXIe 8100 - why?

My client has reported a problem.
For years he has used a PXI 8196 RT Controller with PXI 6602 Counter card and my software has given good results. They have 20+ of these systems and they have worked well.
Now they are moving to PXIe 810x controllers, for cost reasons.
WIth a PXIe 8102, the same code also works perfectly, measuring total counts over a period, as well as instantaneous frequency.
With a PXIe 8100 - the exact same code reports DIFFERENT answers. The reported frequency is always 1% HIGHER than actual (For example, a known 4500 Hz input is reported as 4500 Hz on 8102, but as 4545 Hz on 8100.
This happens on any channel, and swapping just the controller will make the problem come and go.
Here is the CONFIGURE code, where the channels are set up (again, this has worked for years).
Here is the SAMPLE code:
Basically the CONFIG code configures the thing to count edges. I do this because they need an accurate count over a 20-minute period, in addition to instantaneous frequency readings.
The AVG TIME is a user-settable number defining how long a period to average, when showing the "instantaneous" frequency.
So, I create a buffer for N samples, corresponding to that period.
At SAMPLE time, I read the counter. I replace the oldest value in the buffer with the newest, then subtract the newest - oldest to get the total counts in the sample period.
The PULSES PER COUNT item is a scaler, to account for a 60-tooth wheel, or something.
So, this same code has worked perfectly for years, until I plug an 8100 code in. Then the result changes by 1 %, and EXACTLY 1%?
The CPU burden on the bad controller is 31%.
Any ideas?
Steve Bird
Culverson Software - Elegant software that is a pleasure to use.
Culverson.com
Blog for (mostly LabVIEW) programmers: Tips And Tricks

Well, the controllers are not in my own hands. I have an 8196 controller and on that, the CPU time is between 2 and 4%.
But the 8100 and 8102 controllers are in my client's hands.
I haven't gotten any hard timing numbers other than I saw the 31% figure reported on the video monitor.
It's hard to believe that it would be EXACTLY 1% if it was CPU overburden.
My software includes a calibration facility; here is a run from the good 8102:
Here is a run from the 8100:
This was with a reference digital freq generator. You can see the one case where everything is within 0.1 Hz.
the other case has everything EXACTLY 1% higher. My only explanation is that the scan engine is running 1% slower.
Steve Bird
Culverson Software - Elegant software that is a pleasure to use.
Culverson.com
Blog for (mostly LabVIEW) programmers: Tips And Tricks

Three Counters in PXI-6259

Hello Everyone,
I'm trying to measure time t in the picture that I have attached. I am using a PXI-6259 for this (both input and output). My first idea is to use one counter to generate the input, another counter to time when to stop the first counter and the third counter to measure time t. However, I find difficulty in getting the timing correctly, especially, the second timer.
Do you have any ideas on how to do this?
Thanks
Attachments:
picture.JPG ‏27 KB

Hi P.Jack,
I would like to ask for a bit more information about your
project and DUT. Creating a pulse as input for the DUT is not a problem. Examples
can be found in the LabVIEW example finder ((Help >> Find Examples…
>> Hardware Input and Output >> DAQmx >> Generating Digital
Pulses). Please keep in mind that the finite pulse train uses both counters
(one to generate the train, and one to count the number of pulses that have
been generated). Continuous generation only uses one counter, leaving you with
a free one. On that note, I would like add that the 6259 only has two counters.
Is the DUT output a TTL signal ? Also, is this a stimulus
response system, where t can vary in the time it takes? (that is the impression
I gathered from the picture). The overall task you are looking to accomplish
cannot be completely done in hardware with the PXI-6259 because there are only
two counters on the board, and this entire program would require four counters..
If hardware timing is essential, I would suggest a PXI-6602 counter/timer card.
This will allow you to use two counters to create the pulse train, and another
two to do a buffered counter acquisition.
If partial software timing is OK for this project, than the
6259 can accomplish the task. I would do a pulse generation, and then once this
is complete (time T starts), you can clear the task and create a buffered
counter task. Instead of creating another task, you may also think about doing
a digital read on the input line. You would put the read in a loop, and
constantly monitor the line until it goes low. You would put tick counts before
and after the loop, then compare them and see how long it took for the digital
line to go low. Either route is software timed because it requires configuring
and starting a new task at a minimum.
David L.
Systems Engineering
National Instruments

Count the number of Pluses Generated

we are using the pxi-6602(counter/IO) along with SCB-68.
the problem we are encountering is that,we want count the
number of pulses generated.
we are using the counter0 and generating the
pluse, using the example VI Genrate Finite pulse(TIO).VI
which we are able to capure at the CTR0-out.
we want to count the number of pulses generated at
CTR0, so we have connected to the gate of CTR1
and we are running the example vi Measure Pluse NI(TIO)
we are not able to count back the number of pulses generated.
can any one guide us ....
are we heading in the right
1)is it possiblt to count and measure the number of pulse generated.
2)is it neccessary to specify the PFI line in the measuring/counting.
3)output of one counter is connected to gate of the other counter to measure. is it right
4)since this is the first time we are using counter/timers, please guide us, about connecting the
out and source and gate in scb-68.
thanking you
rags

I'm not at a LV PC now, so I can't look at the examples you mentioned. However, the primary problem is that when you generate a finite pulse train on Ctr0, the DAQ driver makes use of Ctr1 to control the # of pulses generated by Ctr0.
Because you have a 6602, you can simply measure the # of pulses with any of the other 6 counters on board. Ctr1, the one you might naturally think to use, is the only one that won't work.
The method will depend on whether you're using traditional NI-DAQ or DAQmx. The example names sound like traditional NI-DAQ, so the simplest thing is to actually wire from Ctr0 output to your measurement Ctr's Source input. Each of the Ctr's has a different PFI pin as its (default) Source input. Summarizing your questions:
1. Yes it's possible to measure # of counts generated by Ctr0 with any Ctr EXCEPT Ctr1. (Note that if you generated continuous pulses with Ctr0, you could then use Ctr1 to count them).
2. It's possible to specify the PFI line for counting pulses. If you physically wire to the default Source input, it won't be necessary.
3. Output of one counter should be connected to the SOURCE of another counter.
4. Ctr0 Out should be wired to, say, Ctr2 Source. Don't have hw here to be able to identify pin #'s.
Final note: under DAQmx, you wouldn't need any wiring. You can programmatically tell any measuring counter to count the edges on any other pulse-generating counter.
-Kevin P.

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

PLL with the Ni 5411 Arb and PXI Star

I am trying to PLL the NI 5411 Arb with the PXI Star, but I have found no documentation indicating how to do it and it does not appear to happen automatically like some other devices. I currently have a 6608 timing card in the PXI Star Slot.

The PXI-5411 is capable of Phase-Lock Looping with the 10MHz Backplane clock and is capable of receiving a trigger signal from the PXI Star Trigger line. However, the PXI-5411 is not capable of driving the PXI Star Trigger.
For more information abotu how the PXI-5411 uses the PXI Trigger Lines, see the "RTSI/PXI Trigger Lines" part of "Chapter 2 - Arb Operation" in the User Manual of the board (linkes below).
NI 5411 User Manual
The Example program attached below (written under LabVIEW 6.1) shows how to synchronize two NI 5411 boards by first Phase-Lock Looping (PLL) their internal clocks with the 10MHz Backplane Clock provided by the chassis, and then sending a trigger line from one 5411 (the master board) to the other (the slave board).
If you want to receive the PXI Star Trigger as the Star Trigger, you will need to use a PXI board capable of sending a signal to this pin. The only NI PXI boards capable of sending a digital trigger pulse over the PXI Star Trigger line are the PXI-5112 (High Speed Digitizer) and the PXI-7344 (Motion).
The PXI-6608 board is not capable of driving the PXI Star Trigger line, however, if you install the PXI-6608 board in slot 2 of the PXI chassis, it will override the 10MHz clock signal provide by the PXI chassis, with the onboard OCXO 10MHz signal provided by the board itself. The PXI-6608 provides a 75 ppb accuracy 10MHz clock, that replaces the aproximately 50 ppm accuracy 10MHz clock provided by the PXI chassis. By overriding the 10MHz clock with a better accuracy one, the PXI-5411 boards will do PLL using a better reference clock.
The only device that PLL automatically with the 10MHz backplane clock are the PXI-6115 Simultaneous Sampling boards.
See related links for more information.
Hope this helps,
Claudia Lorente
Applications Engineer
National Instruments
http://www.ni.com/ask
Knowledge Base 2S2BFCQ7 : PXI Devices That Can Send and Receive Star Triggers
About Your 6608 Device
Knowledge Base 2NFGGQAL : OCXO Stability On The PXI-6608 Counter/Timer
Knowledge Base 2CCF38PQ : Accuracy Problems when I Drive the PXI Backplane Clock with a PXI-6608
Attachments:
5411_Synchronize_Generation.vi ‏229 KB

PXI 6239 counter

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