How is the counter clock chosen?

I understand the the DAQCard6036 has
two clocks for the counter, one is 20 MHz and the other is 100 kHz.
When asking for a pulse train in terms of pulse width and frequency,
how is the clock determined? Is this something I must specify, or does
it happen automatically when using something like Generate Pulse
Train.vi?
Thanks,
Peg

Hello Peg,
When performing a pulse train output, the timebase used is determined by NI-DAQmx automatically. You do not have to explicitly set it. If you would like to know what NI-DAQmx chooses for the master timebase and/or rate, you can use a property node. It is a DAQmx Channel Property Node, and the properties are: Counter Output>>General Properties>>Counter Timebase>>Source, and Counter Output>>General Properties>>Counter Timebase>>Rate.
-Alan A.

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How get the system clock synced?

I messed up the clock sync, because I specified ntp-clock. At the moment the clock is 10 min faster on FI-B (Show clock). I assume this is why I no longer can log into UCSM?
I have rebooted both the FIs, but the clock is still different on the FI-B.
Doing this, does not help:
UCS-A# scope systemUCS-A /system # scope servicesUCS-A /system/services # set clock apr 14 2010 15 27 00UCS-A /system/services #
Message was edited by: Atle Dale at 13:36

this is status now. I hope this is not going to cause problems later, or is causing the other problems I do have:
FI6120XP-B(local-mgmt)# show clock
Thu Aug 9 13:41:18 CEST 2012
FI6120XP-B(local-mgmt)#
FI6120XP-B(local-mgmt)#
FI6120XP-B(local-mgmt)# show clock
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FI6120XP-B(local-mgmt)#
FI6120XP-A /system/services # end
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Buffered event counting. Why can't I explicitly sequence generating the Sample Clock Pulse and reading the counters?

At irregular occasions I need to grab counts from several counters, and buffering the counts must be done simultaneously for all counters. I'm modeling my approach after zone.ni.com/devzone/cda/tut/p/id/5404 which someone kindly pointed out in an earlier thread. However, that example only uses one counter, and you can't test the synchronization with only one counter, so I am using two counters configured the same way, and they're wired to a single benchtop signal generator (for example at 300 kHz).
What I want to do, I can test in a loop with a somewhat random wait in it. I want to drive a hardware digital output line high for a few ms and then low again. The hardware line is physically connected to terminals for my timing vi's Sample Clock Source and so will cause them to buffer their counts for later reading. After I pulse this line, when I know new good buffered counts await me, I want to read both my counters. If their bufferings are simultaneous, then each counter will have counted the same number of additional counts since the last loop iteration, which I can check by subtracting the last value sitting in a shift register and then subtracting the two "additional counts" values and displaying this difference as "Diff". It should always be 0, or occasionally +1 followed immediately by -1, or else the reverse, because buffering and a count could happen practically at the same moment.
When I do this using a flat sequence to control the relative timing of these steps, so the read happens after the pulse, the counters often time out and everything dies. The lengths of time before, during, and after the pulse, and the timeout value for the read vi, and the size of the buffer and various other things, don't seem to change this, even if I make things so long I could do the counting myself holding a clipboard as my buffer. I've attached AfterPulse.vi to illustrate this. If I get 3 or 10 or so iterations before it dies, I observe Diff = 0; at least that much is good.
When I use two flat sequences running in parallel inside my test loop, one to control the pulse timing, and the other to read the counters and do things with their results, it seems to work. In fact, Diff is always 0 or very occasionally the +/- 1 sequence. But in this case there is nothing controlling the relative timing such that the counters only get read after the pulse fires, though the results seem to show that this is true. I think the reads should be indeterminate with respect to the pulses, which would be unreliable. I don't know why it's working and can't expect it to work in other environments, can I? Moreover, if I set some of the pulse timing numbers to 1 or 2 or 5 ms, timeouts start happening again, too. So I think I have a workaround that I don't understand, shouldn't work, and shouldn't be trusted. See SeparateSequence.vi for this one.
I also tried other versions of the well-defined, single sequence vi, moving the counter reads to different sequence frames so that they occur with the Sample Clock Source's rising edge, or while it is high, or with the falling edge, and they also often time out. I'll post these if anyone likes but can't post now due to the attachment limit.
Here's an odd, unexpected observation: I have to sequence the reads of the counters to occur before I use the results I read, or else many of the cycles of this combine a new count from one counter with the one-back count from the other counter, and Diff takes on values like the number of counts in a loop. I though the dataflow principle would dictate that current values would get used, but apparently not so. Sequencing the calculations to happen after the reads fixes this. Any idea why?
So, why am I not succeeding in taking proper control of the sequence of these events?
Thanks!!!
Attachments:
AfterPulse.vi ‏51 KB
InSeparateSequence.vi ‏49 KB

Kevin, thanks for all the work.
>Have you run with the little execution highlighting lightbulb on? -Yes. In versions of this where there is no enforced timing between the counter and the digital line, and there's a delay inserted before the digital line, it works. There are nearly simultaneous starts on two tracks. Execution proceeds directly along the task wire to the counter. Meanwhile, the execution along the task wire to the digital high gets delayed. Then, when the digital high fires, the counter completes its task, and execution proceeds downstream from the counter. Note, I do have to set the timeout on the counter longer, because the vi runs so slowly when it's painting its progress along the wires. If there is any timing relationship enforced between the counter and the digital transition, it doesn't work. It appears to me that to read a counter, you have to ask it for a result, then drive the line high, and then receive the result, and execution inside the counter has to be ongoing during the rising line edge.
>from what I remember, there isn't much to it. There really aren't many candidate places for trouble. A pulse is generated with DIO, then a single sample is read from each counter. -Yup, you got it. This should be trivial.
>A timeout means either that the pulse isn't generated or that the counter tasks don't receive it. - Or it could mean that the counter task must be in the middle of executing when the rising edge of the pulse arrives. Certainly the highlighted execution indicates that. Making a broken vi run by cutting the error wires that sequence the counter read relative to the pulse also seems to support that.
>Have you verified that the digital pulse happens using a scope? -Verified in some versions by running another loop watching a digital input, and lighting an indicator, or recording how many times the line goes high, etc. Also, in your vi, with highlighting, if I delete the error wire from the last digital output to the first counter to allow parallel execution, I see the counter execution start before the rising edge, and complete when the line high vi executes. Also, if I use separate loops to drive the line high and to read the counter, it works (see TwoLoops.vi or see the screenshot of the block diagram attached below so you don't need a LV box). I could go sign out a scope, but think it's obvious the line is pulsing given that all these things work.
>Wait! I think that's it! If I recall correctly, you're generating the digital pulse on port0/line0... On a 6259, the lines of port 0 are only for correlated DIO and do not map to PFI. -But I'm not using internal connections, I actually physically wired P0L1 (pin 66) to PFI0 (pin 73). It was port0/line1, by the way. And when running some of these vi's, I also physically jumper this connection to port0/line2 as an analog input to watch it. And, again, the pulse does cause the counter to operate, so it clearly connects - it just doesn't operate the way I think it is described operating.
For what it's worth, there's another mystery. Some of the docs seem to say that the pulse has to be applied to the counter gate terminal, rather than to the line associated with the sample clock source on the timing vi. I have tried combinations of counter gate and or sample clock source and concluded it seems like the sample clock source is the terminal that matters, and it's what I'm using lately, but for example the document I cited, "Buffered Event Counting", from last September, says "It uses both the source and gate of a counter for its operation. The active edges on the gate of a counter is used to latch the current count register value in a hardware register which is then transferred via Direct Memory Access...". I may go a round of trying those combinations with the latest vi's we've discussed.
Attachments:
NestedSequences.png ‏26 KB

How to make the counter count or start at different time

Hi,
How to let the counter count the time, that doesn't start at the same time ?
This timing system is a sport timing system for canoe competition, it need to track 6 competitor that start at different time .
I have a problem , I have 6 counter in a VI that use to track 6 competitor, but it start count at the same time, how to make it count separately for each competitor ?
Do you guys know how to solve this problem ?
Solved!
Go to Solution.
Attachments:
multi competitor.zip ‏50 KB

HI,
ya, i run it. I mean i know how to make it to 6 competitor already , and yes, it works but the time, it still count or start at the same time. I need to run each competitor at different time , like this competitor A 20-2-2012.VI . This is the one i do but it cant put a stop button. once i put a stop button, the clock stop counting but the whole VI is running.
Regadrs,
Sam
Attachments:
competitor A 20-2-2012.vi ‏139 KB
3switch 3-2-2012.vi ‏14 KB

Counter function : How works the Set attribute function

Hi,
I use Labview and a 6713 DAQ
I want to use the "set attribute vi" but I don't exactly what means the "attribute value number" and the attribute value type" in that vi
>Where can I find some data about that?
>What is the relation between the internal clock frequency and the attribute value number if I generate a pulse train ?
>How can I configure the frequency of my DAQ ? ( I can use 20MHz or 100KHz )
Any help is greatly appreciated
Renaud

Renaud,
You can read the on-line help for the Set Attribute VI by right-clicking over the VI and selecting "Help." The help will describe each of those parameters. In addition, you can search through counter examples for your 6713 by selecting from the menu bar Help>>Search Examples>>I/O Interfaces>>Counters. Any example that demonstrates the functionality of the DAQ-STC counter will work for your board. In addition, you will find examples on pulse train generation.
Hope this helps.
Regards,
Erin

Internal clock for the counter

Hello everyone,
I am new to NIDAQmx and I am doing angular position measurement. I found provided sample for the counter,
it says that I need to use external sample clock. Could someone provide me sample, that uses external clock that was generated by one task
and another task which uses that generated clock and reads encoder input! I am doing it in C++.
Thank you!!!

Hello Khassan,
Here is a link to a Developer Zone article that describes how to implement two tasks that share a clock, The example covers how to implement this with Analog input and output. You can work with it to fit it to your application: http://zone.ni.com/devzone/cda/epd/p/id/2352
Reagards,
-Travis E
National Instruments
Applications Engineer

How can i get the count vaule from GPIB?

I want to get the count waule from GPIB ,but I find that the vaule I get from GPIB now is the trace vaule ,
so I ask How can i get it.

The count of what? What kind of instrument are you using?

How can I disarm the counter in a specified time?

I am using 6602 counter. I use 2 counters to perform "Buffered Period Measurement ". I use internal time base (20MHz) as the SOURCE, and wire the signal to the Gate. The counters are triggered by a trigger signal.
Now I just want to stop counting the signal in a specified time after the counters triggered. After that time, even the input signal is still running,the counting must be stopped. How can I implement this purpose? I don't know how to disarm the counter when the counter are still running, and how to exactly determinate the stop time.
Thanks for any advise. I have attach my present routine here.
Attachments:
counters.vi ‏192 KB

Just to expand a bit on Justin's answer to outline a few particulars.
You mentioned using 2 counters to capture buffered periods so I'm assuming that you'll enable triggering to guarantee that they both have the same start time. Note that in this scheme, element #0 of your array of buffered periods will represent the time from the Trigger edge until the first Gate edge.
Since your description made it sound acceptable to ignore pulse periods occurring later than the interval of interest, perhaps you can collect data for a little longer than necessary, then reset the counters and trim off the periods that came in "too late" using 'Array Subset.' A quick-and-dirty way is to loop over each array of periods, performing a cumulative sum until it exceeds the specified data collection time interval. That'll tell you the length of the subset you need to keep.
The hard part is that after starting the measurement, you'll need to poll task attributes/properties to determine when the trigger has been received. Only after that's been determined would you start keeping track of approximate time in software.
There are ways to do the timing in hardware if you get more of the 6602's counters involved. Here's one way:
1. First configure your 2 counters for buffered period measurement. However, instead of using the internal timebase for a Source, use another counter's output as a Source. Under DAQmx, the internal routing details are handled for you; under traditional NI-DAQ, you'll need to make explicit routing via RTSI.
Note that in this scheme, these 2 counters don't need to be triggered.
2. Next, generate a finite-duration pulse train at 20 MHz (examples can be readily found under LabVIEW help or this website). This pulse train should last for your data collection time interval, and will act as the Source signal for your period measurements. It is important that the period-measuring counters are started before the finite pulse train.
The finite pulse train uses 2 counters -- one to generate the output pulse train at 20 MHz and a "helper" that produces a single pulse whose duration equals your data collection interval time.
If you need to synchronize to some external trigger signal, you can set the "helper" counter to be triggered, but there'll be one subtle catch. The first period measurement in your buffers will not include the time from the external trigger signal until the beginning of the single "helper" pulse, i.e., the "delay" time spec for the pulse. You can either make this very very short and ignore it, or make it any convenient duration and then add it to the first period measurements. Be careful though: the timebase for this "delay" time isn't necessarily the same as the timebase used to measure periods.
There's quite a bit of complication there, so let me suggest an easier way that assumes no need to synchronize to an external trigger. (I'll use DAQmx terminology, since the traditional NI-DAQ would get complicated again with explicit RTSI signal routing.)
A. As describe in #1 above, configure your period-measuring counters to use a 3rd counter's output as the timing source terminal.
B. After starting your 2 period-measuring counters, start up the 3rd counter to generate a continuous 20 MHz pulse train.
C. After the 3rd counter starts, call the 'Wait (ms)' function from the Time & Dialog palette. Wait for slightly longer than your desired collection time.
D. Read all buffered periods from the counters. You may need to first query each to find out how many are waiting to be read.
E. Reset all 3 counters.
F. Do the cumulative sum work on the two buffered period arrays to determine where each should be truncated.
Note that step "C" above will leave you stuck while data is being collected. A small variation would be to read a reference time ("Tick Count (ms)") right after starting your 20 MHz counter, then set up a loop that allows you to terminate early (logical OR of, say, "abort" button, data acq error cluster error, and time comparison). In that loop, you put a delay of maybe 50-200 msec using "Wait (ms)."
"Wait (ms)" will output a tick count from which you subtract the reference time. When the difference exceeds your data collection time, you can exit the loop and continue with step D above.
-Kevin P.

How do I use the counter and digital signals of the 6071E while it is connected to SCXI modules?

I am contemplating using a PCI 6071E with SCXI. We have the boards (6071E), we would need the cable (I suppose SH1006868) and the SCXI system. I would like to know how would you access the counter and digital line capabilities of the board. I will be using a SCXI-1314 with a SCXI-1520 Module for strain measurements but will need to use the counter and digital lines of the board as well. Can this be done? If so, how and/or what else do I need?

I think this KnowledgeBase will answer the question for you.
Accessing DAQ Board Counter Pins with an SCXI System
Otis
Training and Certification
Product Support Engineer
National Instruments

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Hey there Luba_kalstad,
It sounds like you are unable to join your network and cannot see it in the Wi-Fi list in Settings. I would try the troubleshooting outlined in this article named:
iOS: Troubleshooting Wi-Fi networks and connections
http://support.apple.com/kb/ts1398
Be sure you're in range of your Wi-Fi router (access point).
Tap Settings > Wi-Fi and turn Wi-Fi off and on. If your Wi-Fi setting is dimmed, follow these steps.
Confirm that your Wi-Fi router and cable or DSL modem are connected to power, turned on, and connected to the Internet. If not, refer to your network administrator or Internet service provider (ISP) for assistance.
Restart your iOS device.
Tap Settings > Wi-Fi and locate the Wi-Fi network to which you're connected.
Tap and Forget this Network.
Try to connect to your desired Wi-Fi network.
Note: You may need to enter your Wi-Fi password again if your network requires one.
Turn your Wi-Fi router off and on2. If your ISP also provides cable or phone service, check with them before attempting this step to avoid interruption of service.
Update your device to the latest version of software.
Update your Wi-Fi router to the latest firmware2. For AirPort Base Stations, install updates using the AirPort Utility.
And this section down toward the bottom if needed:
Unable to locate a Wi-Fi network
Verify that the network is available by tapping Settings > Wi-Fi and choosing from the available networks.Note: It may take a few seconds for the Wi-Fi network name to appear.
Move closer to your wireless router (access point) and attempt to locate the Wi-Fi network.
If you do not see the network you would like to join, you may be attempting to connect to a hidden network. Learn how to join a hidden network.
Supported Wi-Fi configurations vary by iOS device model. Find out which standards your device supports3.
Reset network settings by tapping Settings > General > Reset > Reset Network Settings. Note: This will reset all network settings including:
previously connected Wi-Fi networks and passwords
recently used Bluetooth accessories
VPN and APN settings
Thank you for using Apple Support Communities.
Take care,
Sterling

How do I count the number of unread emails in WebCenter ?

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Hi Euler,
interestingly enough, the reference guide for CMIS ( http://wiki.alfresco.com/wiki/CMIS_Query_Language ) that I found does not mention the COUNT function at all. On the other hand it states that: "The SELECT clause identifies which virtual columns to return in the result set. It can be either a comma-separated list of one or more queryNames of properties that are defined by queryable object types or * for all virtual columns."
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Hi Euler,
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How to display a row in Cross Tab when the count summary is zero

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This worked for the last guy who had a similar issue.
Take a look at what it's doing. You should be able to use the same principal to meet your needs...
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I don't know how your data is coming across but the formula should go something loke this:
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How to display the count of a list item in Sharepoint Designer?

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Hello,
What version of sharepoint you are using? Try below approach:
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Hemendra: "Yesterday is just a memory,Tomorrow we may never see"
Whenever you see a reply and if you think is helpful, click "Vote As Helpful"! And whenever
you see a reply being an answer to the question of the thread, click "Mark As Answer
Please feel free to unmark answer if does not resolves your problem.

How is the counter clock chosen?

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