Route multiple 6602 counter inputs to one counter output...

Hi!
I´d like to route 4 different ttl signals, that are read by 4 different counter inputs to one single output channel (e.g. the output of one of the counters used) using pulse train generation with a divider of 4. Note that only one of the four inputs is active at the same time, to prevent overlay.
How can I do that with Traditional-DAQ?
Setup would look like this on the SCB-68
TTL1 ----o in0 (ct0)----o out0 TTL(1..4)/4 [Hz]
|
TTL2 ----o in1 -- (output of ct2 is redirected ro ct1)
|
TTL3 ----o in2 --
|
TTL4 ----o in3 (ct3)--
May it be better to just output each counter input signal at it´s own output and connect these outputs to one free I/O-pin hardwired?
Best regards
Zorniki

In the end I configured a counter for Pulse Train generation and opted to change the duty cycle and frequency via 'DAQmxWriteCtrFreqScalar" (i.e. Pulse Width Modulation)
I registered a callback for the 'DAQmx_Val_CounterOutputEvent' and then changed the dutycycle and frequency in that callback.
Unfortunately, I kept getting "The pulse generation with previous property settings must complete a
full cycle before the property can be updated." error messages and, opon further reading, managed to find a doc where National Instruments suggest adding a 'Wait(period)' before executing the 'DAQmxWriteCtrFreqScalar' call.
The problem with this solution is that it one has to wait a minimum of 2 Periods before the Pulse Train can be modified which is not acceptable for our work.
So is there an alternative solution which allows us to change the Pulse Train after only 1 Period ? Is there an event we can trap which allows us alter the Pulse Train after every period ? I'm sure PWM must be possible on Daq cards (PCI-6602 or PCI-6281 or PCI-6259)?
Cheers, Shaun.

Similar Messages

Processing counter input into an analog output

Greetings to all --
I've set up a PCI6070E card to do digital input through its "counter 0" channel and output through its "AO 0" channel.
I'm brand-new to Labview, however, and having trouble figuring out how to design my program. In short, this is what I want to do:
1. Count the number of pulses, let's call it P, that arrive at the counter in a given time increment. (Ideally, this time will be adjustable from 1 microsec to 1 sec. In reality, I may have to settle for some number of milliseconds or more, as Labview doesn't seem to like to do loops at more than 1khz. But that's an issue for another day.)
2. Perfrom a mathematical operation to turn P number of counts into some number N between -10 and 10
3. Set the analog output to read N volts
4. Reset counter to zero and start over at (1.) again.
I can make labview count pulses in, and I can send voltage signals out, and I can use the front panel to get the inputs I need from the user for the mathematical operation, However, I'm having trouble with counting how mant pulses hit in a given time increment, and then resetting my digital counter to zero.
Can anyone point me at the right function names or help files, or suggest a rough program flow? I appreciate it.
Chad
[email protected]

Chad,
The only way you can perform this type of operation with your device is in software. See the knowledge base entries below for more details.
HW resetting Counter on an STC Device:
http://digital.ni.com/public.nsf/websearch/55AF6CADD87F6F7786256B89005B8AFD?OpenDocument
How To Reset in Software:
http://ae.natinst.com/operations/ae/public.nsf/web/searchinternal/65e3dbc715998c3286256e900075b7f8?O...
Regards,
L. Allen

Counter Input with Delayed counter Output with board 6023E

HELLO
Is possible with board 6023e have two counters working at same time in this case i need a counter to creat a delay and another one to read. If isn´t possible how i can have a delay in microseconds.

Yes, each one of those boards have two STC counters you can use. Take a look at the User Manual of the boards for more information. When looking at the pin diagram for the boards, the counter pins are GPCTRx_.
If you are using LabVIEW, CVI, VB or VC++, when you install NI-DAQ, it will install a lot of counter example programs which will show you how to program the counters.
Brian

How do I use one audio jack as input and one as output?

On my MacBook Pro, if I get a USB-headphone connector (to add another audio port), will I be able to set one audio port as input and the other as output? To use the port coming out of the USB jack as a headphone jack, and plug a mic/output device into the computer's port?
I'm thinking about buying a "Sabrent USB External Stereo Sound Adapter". I have a preamp that is NOT an interface, and I want to be able to monitor what I'm doing so I can multitrack. But my MacBook only having one audio 1/8 inch jack makes it so I have to choose either input OR output...I'm hoping if I add an extra port via USB I'll be able to have one of each.
Thank you!

Roger Wilmut1 wrote:
nategm wrote:
On my MacBook Pro, if I get a USB-headphone connector (to add another audio port), will I be able to set one audio port as input and the other as output?
Yes, either way round. In System Preferences>Sound you can set the input and output ports separately.
Roger, the System setting have -Nothing- to do with the question being asked. Do you use Logic Pro audio software? If you did you would know Logic has it's own audio settings that run independently from the System audio. There's also the fact that Maverick has problems with "some" older USB 2.0 audio hardware. Basically, this is not a slam-dunk, that's why I suggested asking someone if they've used this combination before. Although... the USB audio device is cheap ($10) it might be worth it to try. Still.............**
** I question the wisdom of using cheap audio hardware on a computer that cost $1000+, software that costs $200 and then using the internal audio chip ($2) and an external monitoring device that costs $10. Defeats the whole purpose of using professional audio software.

Two counter inputs and counter output NI 9401

I am trying to configure two counter inputs and one counter output on one NI 9401. I have looked and found how to configure digital lines in booth directions but it seems like I can only do two counters in all on one module. Can someone verify this for me or let me know how to get all three on to one module?
Thank you

Hi mschoenwald,
The counters are actually located on the backplane of whatever chassis you are using--I'll assume you are using cDAQ and not cRIO.
If you have the older <link no longer exists>, then there are only 2 counters available in general. You can access both from a single parallel (8 lines or less) digital module in slot 5 or 6 of the chassis.
The 2nd generation Compact DAQ chassis (including 9174, 9178, 9181, 9188, etc.) includes 4 counters. You may access them from any slot with a parallel module. There is no restriction preventing you from accessing all 4 simultaneously from a single module.
The 9401 is bi-directional and configurable by nibble (line0:3 may be configured one direction, and line4:7 another). However, it is quirky in that it requires the line direction to be configured before any of the tasks are started. This is because the data lines themselves are used to set the line direction behind the scenes. The best way to work around the behavior is to use DAQmx Control Task to explicitly reserve your tasks before any of them are started (see here). Keep in mind that the counter output should use the opposite nibble from the two counter input tasks.
Best Regards,
John Passiak

How do I program a NI 6602 card to send trigger pulses, one at each output port, triggered by an input trigger signal, using only one counter for each output port?

Hello,
I have managed to program a NI 6602 card in LabView to send pulses on three different output ports, one pulse on each output port (with individually chosen delays) for each input trigger pulse coming on a separate input port. It is the DAQmx Create Channel (CO-Pulse Generation-Time)-VI that I have used for this, see attached code. However, this VI controls both pulse delay and pulse width, and therefore uses two counters for each output port (although you only specify one counter in the VI input signals), as I understand.
In my application though, I only need to have the delay chosen, the pulse width can be arbitrarily short, and thus I should only need one counter for each output port. How do I accomplish to program this in LabView?
Best regards,
Claes
Attachments:
Configure Side Camera Flash 1 Triggering.vi ‏47 KB

Well you're welcome to do that--it will work just fine as long as you are configuring a start trigger.
<rant>
However, personally I really don't like putting multiple counter outputs in the same task. I have seen so many people assume that the counter outputs would be synchronized due to having them in the same task when this is not the case (you need to configure a start trigger in order to synchronize the counter outputs even if they are in the same task). This is the only case I can think of where multiple channels in a DAQmx task are not automatically synchronized.
As an example:
Running this on my PCIe X Series gives a measured 2 edge separation of 1 ms + {7.78 us - 10.11 us}. This would likely be much worse on a bus with more latency (e.g. USB).
The resulting output is close enough to what you might expect that it might go unnoticed, but really these counter outputs are not synchronized and it would be easy to glance at the code and not even think twice about it. For the small amount of extra work on my end to create a separate task for each counter, it really clears up some ambiguity about what the counters are actually doing. For me it's worth it.
So again, for your case there really isn't a problem with having the counters in the same task since you are using an external start trigger anyway. I have just gotten in the habit of avoiding doing this.
</rant>
Best Regards,
John Passiak

PCI-6602 - What to do with unused counter inputs?

I've got an application where I need to track the position on two quadrature encoders. I've developed my application with VB6 however, I've been using a sample LabView program called "Meas-Ang-Pos-Buff.vi" for testing purposes. (I got the example off the NI discussion board). I'm seeing some very odd results that I can't explain.
For testing purposes, I've got one encoder tied to multiple channels on my 6602. I have the same 'A' signal and the same 'B' signal (from the one encoder) jumpered to multiple encoder channels. I'm using a onboard pulse generator to generate the latch pulse (connected to the Index/Z of each counter) to ensure there is no skew in my count values. I'm using an external servo to turn the encoder at a rate equal to my application speed.
The unexplanable results I'm seeing are below:
If I'm monitoring counters 0, 1 and 2, I see the following.
1) If I have counters 0,1,2 and 3 inputs connected to the same 'A' & 'B' from my encoder, the counts on all 4 channels (0,1,2,3) track perfectly.
2) If I disconnect counter 3 and only have counters 0,1, and 2 connected to the encoder, then counter 0 and 2 track perfectly, but counter 1 looses pulses (only when traveling in one direction, the other direction seems to be fine)
3) If I connect counter 3 to ground and have counters 0,1, and 2 connected to the encoder, I get the same result - bad.
4) If I connect EVERY counter input (2,3,4,5,6) to ground and only monitor counters 0 and 1, I still get bad results.
In summary, I ONLY am able to see the same number of counts while monitoring 3 channels IF 7 of the 8 counters are connected together (the 8th being my latch).
This happened to me in the past on a previous setup that did the same thing, but I was able to fix it by moving from counter 1 to counter 4. At that time, I chalked it up to a bad counter 1, but I think there is a bigger issue since it is happening again.
Please any advice would be appreciated.

Thanks for the response. This one has really got me confused and any help is greatly appreciated.
To answer your questions, no I have not modified the sample program and I'm using NI DAQ v8.5.
I've decided to break the problem down to see if I could find a pattern, but no such luck. Here is the testing that I've done.
I'm making the following connections while using the sample program I mentioned earlier:
Counter 0...............PFI_39 (term 02) - Channel_A(0).................PFI_37 (term 40) - Channel_B(0)
Counter 1...............PFI_35 (term 07) - Channel_A(1).................PFI_33 (term 06) - Channel_B(1)
Counter 2...............PFI_31 (term 34) - Channel_A(2).................PFI_29 (term 66) - Channel_B(2)
Counter 3...............PFI_27 (term 31) - Channel_A(3).................PFI_25 (term 63) - Channel_B(3)
Note: I connect the "Z" channel for gating purposes in my VB application, but this isn't required in the LabView sample program since the gating appears to be done internally.
My testing results:
1. If I jumper my one encoder to channels 0,1,2, & 3 at the same time, everything works great. Each channel reports the same number of counts regardless of whether I'm turning the encoder in the positive or negative direction.
2. If I disconnect channel 3 and only have 0,1 & 2 connected, then 0 & 2 track perfectly, but channel 1 looses counts in the negative direction.
3. If I only connect channels 0 & 1, then channel 0 counts perfectly in both the pos and neg direction, but channel 1 looses counts in the negative direction.
4. If I connect any channel by itself (0,1,2 or 3), each one counts perfectly.
5. If I connect channels 0 & 4, everything seems to be fine.
Like I said in my previous e-mail, if this hadn't already happened to me in a previous application, then I would chalk it up to a bad board. If I didn't get good results on each individual channel then I would chalk it up to a bad encoder pulse train. However, it definitely seems to have something to do with connecting multiple counters at the same time in a Motion Encoder Application. I have read the 6602 User Manual backwards and forwards looking for a nugget of explanation, but have found none. There was a section entitled "Counter Input Selections" on page 4-12 (table 4-2) that might offer some explanation, but neither me or my colleagues could understand what was being described. Any help deciphering that would be appreciated.
As of now, I'm going to proceed with my application, using channels 0 &4 (just as I've done in the past), however I don't feel comfortable not having an explanation for the 6602's behavior. Any insight would be greatly appreciated.

Can source and gate used to measure 2 signals using one counter?

I have one PCI 6602 card to measure measure the frequency. PCI 6602 has 10 channels, in which channel 5 and 10 doesn't have 'source' terminal.
We have to measure frequency from 16 signals using one PCI 6602.
From channel 1 to 4 and 6 to 9, we have 8 'Gate' and 8 'Source' terminals.
We have connected 16 signals to these 16 terminals.
At any given point of the time we want to measure either 'Gate' signals(8) or 'Source' signals(8).
Can any provide any guidance to make a program in labview to measure frequency (period) as per above given points?
Regards
Vijay

Hello Vijay,
It takes one counter for each digital frequency you want to measure and the PCI-6602 has 8 counters total. This means that the maximum number of digital frequencies you can measure is 8. If you want to measure 16 frequencies you'll need 16 counters.
Single counter frequency measurements are made by comparing the board's time base (80 MHz) to an external frequency. The board counts the number of time base periods that occur during one period of your incoming frequency. When you configure the board to take a single counter frequency measurement the card routes the time base to the source of the counter and then you connect the frequency you want to measure to the gate of the counter.
Here are a couple of articles that explain how these measurements are taken and calculated. (The second article is on period measurements so for frequency measurements you measure period and take the inverse):
Making Accurate Frequency Measurements
Period Measurements with a Counter
There are example programs available in the LabVIEW example finder. You can locate these by going to Help>> Find Examples... The examples you want is: Hardware Input and Output>> DAQmx>> Counter Measurements>> Digital Frequency>> Measure Digital Frequency- Low Freq 1 Ctr.vi.
I hope this explains how counters work and why you need one counter per measurement.
Cheers,
Brooks

Counter input problem

hi, i'm using a counter input to count the falling edges of a digital pulse. I need to convert this into a time based measurement (period/frequency), but am having a litle trouble doing this. If any one can help? i'd prefer it if it were as simple as possible, i.e. no fancy programming as I'm new to LabVIEW and would like to fully understand what i'm looking at!
Many thanks in advance!
tom

Hi
What version of LabVIEW are you using? If you're programming with version 7.0 or higher you can configure your counter for period or frequency measurements quite easily using the DAQ Assistant.
Just drop down the DAQ Assistant Express VI. The Wizard that opens will ask you to choose your input type. Choose Counter Input and it list options for Edge Counting, Frequency and Period Measurement. Choose the one you want then choose the counter with which to do the measurement. When you click Finish a configuration dialog box will open up for you to configure the Input Range, the Task Timing, etc. There will also be some further information in the help section along the right of the window. When you click OK the DAQ Assistant will build your code.
I've attached a Zip file with 2 labview programs to demonstrate this. (They're written in version 8). Connect DIO 0 to PFI 9 of your DAQ card (I'm using an M Series card. If you're using a different card let me know). Extract and run both files. The Digital Output VI generates an alternating high and low signal for each iteration of the loop. The Counter Frequency Measurement VI measures the frequency of this output. The frequency is determined my the Wait Until Next ms Multiple function so change the input to that to vary the frequency.
Let me know how you get on with that and if you require more info.
Good luck!
SarahB
NI | UK
Sarah
Applications Engineer | National Instruments | UK & Ireland
Attachments:
Frequency Measurements.zip ‏65 KB

Encoder position WITHOUT counter input

Question:
I have three incremental encoders connected to my M-Series DAQ board (PCI-6229) that has TWO Counter input channels. I am measuring the position of each encoder. How do I measure the position of the third encoder if I have used-up both counter inputs? Is there a manual way to accomplish this using my older version of Labview (version 7 express)? Any help is appreciated.
-Clarkam1

clarkam1 wrote:
Ben,
I'm on an extremely small budget and can only use the items available to me at present time. That being said, is there no way to use one counter for multiple encoders? Or could an external device be used to count which the DAQ board would read? I appreciate your timely responses. I'm trying to explore all other options.
So do you work for free?
If you are determined to get all three counters going with that device, you have a big challenge ahead of you. I'll try to explain. At teh input of your counters you have signal conditioning that feeds the counter itself. To do the same thing using analog input channels (since all of the counters are already used) you will have to develop code that simulates the signal conditioning, converts the analog to digital (this may sound easy but if you need to implement over-sampling its not) and then do the work of the counter, again in software.
If my customer was forcing this on me I would first review the behavour of the hardware and use it to establish the requirements of my code. So if you do not have an EE background, you will first have to learn the hardware so you can write software that does the same thing.
So if you work for free then you may want to chase down the examples that NI ships for their FPGA targets that implement serial protocols and the like. You may be able to harvest some code and examples from there. If you don't work for free, then you really have to decide if you want to re-invent in software what you can purchase.
Ben
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

4 counter input & 6 signal input HELP

Hello Friends,
I have a little problem, would be great if someone can help me.
I am using the counter inputs on my Data Acq. Harware to measure the pulse width of my input sigal.
Since the hardware has only 4 counter inputs I can connect 4 channels, but I want to measure pulse width for 6 channels.
Is there a way to use the available 4 counters and measure all of the 6 channels?
Thank you
Regards,
Raj
Solved!
Go to Solution.

In my (very basic) example, you could just increase the timeout to ~10+ seconds to ensure you acquire the pulse. If it's possible that the pulse isn't present within the ~10+ second timeout you would also need to handle the timeout error so it doesn't wrap back around through the shift register and prevent the future reads from executing.
The downside to this of course is that it could take up to ~60+ seconds to acquire from all 6 channels in the worst case scenario. The example was really just intended to show how one might use a single counter to acquire from multiple channels in succession.
The better way to do it with counters would be to run (up to) 4 counter tasks in parallel. The first 2 tasks to finish with their original acquisition should then measure a second channel. This could still take ~20 seconds if none of the signals are connected however.
If you want to trade a lower measurement resolution (and more memory usage) for a lower upper-bound on measurement time you could instead acquire a 10 second window of time using clocked digital inputs and use software to determine the pulse duration by parsing the acquired array.
Best Regards,
John Passiak

Can I generate pulse trains on more than one counter output at the same time?

I have a PCI 6601 card with a BNC 2121 to connect the signals to two devices. The card is used as a trigger for both devices and I want to be able to generate pulse trains on two output channels at the same time, with a time delay between the two. How do I do that in Labview 7.1 Development with DAQmx?

I feel foolish for not being able to figure this out, but it still doesn't work. Attached is the VI I use now. Counter 0 generates a finite pulse train and I programmed Counter 1 to generate a retriggerable single pulse triggered by CtrOinternaloutput. I still get the same error message: -50103 The specified resource is reserved. The operation could not be completed as specified.
The same happens if I set the trigger for counter 1 at PFI36 (default output of counter 0) or any other PFI line. If I try a pulse train generation on only one of the counters, both work fine.
If I try the example in traditional DAQ for multiple counter outputs with phase delay, it works fine.
Can you tell me what I'm doing wrong?
Attachments:
Shutter_AND_lamp_trigger.vi ‏103 KB

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

6251 Counter input signal

Hello,
I am acquiring pulses which are 0-5V with the counter of the PXI 6251. However, I would like to know if it is possible to acquire pulses that are, for example 0-12V or 0-24V without damage the device. In other words, which is the voltage range for the counter input in a PXI 6251?
thanking in advance,
CJMV

Hi,
You will not be able to use the counter directly but you can setup an analog level trigger for your signals. This will create a pulse that isTTL compatible for you everytime the signal crosses a particular level. Then you can route this into your counter and perform any counter measurements on it. An example is this is shown here where it sets up a level trigger to make frequency measurements.
Alternatively you can purchase an industrial strength digital I/O board such as the USB-6525 but this does not include a counter.
Please let me know if this works out for you.
Message Edited by Abhinav T on 07-06-2007 05:20 AM
Abhinav T.
Applications Engineering
National Instruments India
LabVIEW Introduction Course - Six Hours
Getting Started with NI-DAQmx
Measurement Fundamentals

Using one counter with FiniteSamps and another with ContSamps

I am trying to use 2 counters on the USB-6229 (or USB-6259), where one counter is set up for FiniteSamps and another for ContSamps. I have the following MeasurementStudio code:
ErrChk DAQmxCreateCOPulseChanTicks(hCnt0, "Dev1/ctr0", "", "20MHzTimebase", DAQmx_Val_Low, 0, 400, 400);
ErrChk DAQmxCfgImplicitTiming(hCnt0, DAQmx_Val_FiniteSamps, 100);
ErrChk DAQmxStartTask(hCnt0);
ErrChk DAQmxCreateCOPulseChanTicks(hCnt1, "Dev1/ctr1", "", "20MHzTimebase", DAQmx_Val_Low, 0, 400, 400);
ErrChk DAQmxCfgImplicitTiming(hCnt1, DAQmx_Val_ContSamps, 2);
ErrChk DAQmxStartTask(hCnt1);
When I run it, I get a run-error 50103 "The specified resource is reserved". If I change the FiniteSamps to ContSamps on the first counter, everything works fine.
If I use only one counter with FiniteSamps, everything also works fine.
Is this a bug in DAQmx or the dual counter use on M-series devices is limited to ContSamps?
Vic
Solved!
Go to Solution.

Hi Vic,
This is actually expected on an M Series device. Here's a timing diagram from the M Series User Manual that might make this a bit more clear:
The device actually uses one counter to gate the other so the result is a finite pulse generation. If you can provide the gate from another source, you may configure a continuous pulse generation on both counters and gate them (DAQmx calls this a "Pause Trigger") from this external signal.
You might also want to look into using Correlated Digital I/O to generate multiple finite pulses (up to 32 lines on your 6229 and 6259). You could use one of the counters to generate a timebase for the digital lines, and build the waveform accordingly.
One thing to note is that our new X Series boards can generate a finite pulse generation on a "single" counter (there is actually a paired internal counter that allows for this). There are four user-accessible counters on X Series devices, meaning you could generate four finite pulse trains.
Best Regards,
John
John Passiak

Route multiple 6602 counter inputs to one counter output...

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