Read analog trigger signal gated by digital pause trigger

Hi!
I want to use and analog trigger together with digital pause trigger. At the same time i want to see on the scope the analog trigger signal which was gated by gate signal. Is it possible? Can i somehow wire the gated trigger to one of the outputs of the board?
Thanks in advance.

Hi Sergei_phys,
Thank you for the forum post!
I have a few questions about your post:
What hardware are you using? Is it NI or 3rd party? You mention using a scope, is that a NI piece of hardware/module?
In theory you can have a analog trigger to start the acquisition and a digital trigger to pause , but it depends of the hardware.
Thanks,
DanC12

Similar Messages

DAQmx: Gating Pulses with Pause Trigger

I have an NI 9401 module in a 9171 chassis and would like to gate the output of one counter with the output of another counter. Counter 1 (the signal to be gated) generates a 3 Mhz signal and Counter 0 (the gate) generates a 10 Hz signal that is externally routed to Counter 1's Gate pin. I expected this would gate Counter 1's signal to produce the 3 Mhz pulse only when Counter 0 is high, but the wiring had no affect on the output of Counter 1, it still generated a continuous 3 Mhz pulse train. I found that some code is needed to get a counter to pay attention to the signal at its Gate pin (this post was particularly helpful) and that this can be done with the Pause Trigger property node. After setting up the node, however, I ran into this error:
Error -20124 occured at DAQmx Start Task.vi:2
Lines 4 to 7 of this port are configured for input. Cannot configure these lines for output at this time.
I'm pretty perplexed by this. The problem seems to be coming from trying to designate PFI 5 ("CTR 1 Gate" on the 9401) as the Pause Trigger source. If anything, I would think the error would be that lines 4 to 7 are configured for output, since those lines are grouped under CTR 1 which is configured as a CO channel to generate the 3 Mhz pulse train, and that setting line 5 as the Pause Trigger source is changing the configuration to an input. Searching for this error in the NI forums and Google doesn't pull up any troubleshooting information. I've tried to create a task to configure line 5 as a seperate digital input channel, but then I get the opposite error (Error -200125) saying that lines 4 to 7 are configured for output and cannot be configured to input, to make things more confusing.
Any thoughts would be appreciated. I'm concerned that I'm missing something obvious about gating pulses or configuring CO channels since I keep reading that one of the advantages of DAQmx over DAQ Legacy is that it makes signal routing easier. I'm using LabVIEW 2012 (32-bit) with DAQmx 9.5.5 installed.
Solved!
Go to Solution.
Attachments:
Simple_Gated_Pulse.vi ‏29 KB

Hi agoncalves,
I took a quick look at your VI and I see two immediate problems:
1. There is not guarantee that both tasks will reserve before either one starts. This explains your error and why it seems confusing. The 9401 is nibble configurable but you can't change the direction while the device is in use (why the reserves are important). The module powers up with both nibbles set to input. Your first task drives an output so it switches direction on one of them. When your task is committed (started) it locks in that configuration. The second task then tries to also drive an output but on the other nibble which is input and cannot be switched because the first task is running. The solution is to use the error wire to force the execution order (or use a flat sequence structure).
2. You'll run into problems with your gating signal unless you wire it into a separate input (and put both pulse trains on the same nibble). You can change that by setting the channel property CO.Pulse.Term. That's if you want to route your signal through some external circuitry and back in. If you are using the signal directly, you could just use it internally. Such as /cDAQ1Mod1/ctr0InternalOutput

Edge counting with digitial pause trigger

Hi
I should write a program for edge counting with digital pause trigger in visual basic. I have found an example of using pause trigger in edge counting but it is written in C#.
Steps in the program followed is:
1) creating task
2) creating count edge channel objecy
3) configuring thr trigger ( where i have been strucked)
code in c # is:
taskname.triggers.pausetrigger.digitalleveltrigger ( source, level)
When i tried to look for trigger function and to configure it in Visual Basic, I have not found any trigger function to set/configure in the function library
Thanks

Hi there,
Here is the code in text format. That's pretty much all you need. I took the example code called CntDigEvents.vbp and added the following code before the start task function call:
    DAQmxErrChk DAQmx.DAQmxSetPauseTrigType(taskHandle, DAQmx_Val_TriggerType6_DigLvl)
    DAQmxErrChk DAQmx.DAQmxSetDigLvlPauseTrigSrc(taskHandle, "PFI0")
    DAQmxErrChk DAQmx.DAQmxSetDigLvlPauseTrigWhen(taskHandle, DAQmx_Val_Level1_High)
As for the C# code I am not familiar with C# so I don't think I can be a great help on that one.
myTask.Triggers.PauseTrigger.ConfigureDigitalLevelTrigger(triggerSourceTextBox.Text, gateLevel) This function is the main call for the pause trigger and all it is doing is setting the properties. triggersource should be along the lines of "PFI0" or "Ctr0" and gate level defines whether the gate level is "high" or "low)
How is the VB code going?
AdamB
Applications Engineering Team Leader | National Instruments | UK & Ireland
Attachments:
VBcode.txt ‏4 KB

Convert a rpm waveform to digital/analog tach signal. Sound & Vibration

Hello,
my question is: How to convert a rpm waveform to
digital/analog tach signal for use with SV application?
Or is it possible to modify the SV - VIs for the use of
a rpm waveform or a speed signal?
Thanks a lot for coming answers.
Thomas Nuding

Typically an RPM waveform is the analog view of a tachometer, such as a proximity probe over a key or keyway, or an index pulse from an electric motor. In most rotor dynamics applications, the phase of the tachometer waveform is compared to the phase of other waveforms, such as vibration, to determine the angular position of the shaft when the other waveform occurs.
The sound and vibration tools have a function for calculating RPM from an analog tachometer waveform. The order analysis toolset go further to add a counter as an tachometer input. The OAT tools also allow for selection of rising edge or falling edge and voltage level for the "trigger". A time instance is recorded when the edge occurs. This time instance is used for phase measurements and for resampling the other waveforms into the angular domain, ie. 360 measurements per revolution.
Preston Johnson
Principal Sales Engineer
Condition Monitoring Systems
Vibration Analyst III - www.vibinst.org, www.mobiusinstitute.com
National Instruments
[email protected]
www.ni.com/mcm
www.ni.com/soundandvibration
www.ni.com/biganalogdata
512-683-5444

No digital trigger signal on a PFI x-port in a PCI-6259

Hi,
I am using a PCI 6259 DAQcard (with a SHC68-68-EPM cable and version:2.9.1f0) to get an analog signal and a digital signal. The analog signal is used in NI MAX or NI Signal Express (DAQmn 9.7.5) to trigger it with the digital signal. When the digital signal is mounted on a Px/x port I can detect it. If I want to use it as a trigger signal on a PFI x- (better PFI x/Py.y-) .port I do not get any trigger quantitiy.
With a NI USB 6008 everything works quite well. Remark: The digital post is just labled as: PTI 0 and not as in the case of the PCI 6259 on the NI CB-68LPR-board: PFI x/Py.y.
Another remark is that I did not measure a voltage difference of 5 volt at the provided port.
How can I fix the problem and use a PFI x/Py.y-port for a digital trigger?
Solved!
Go to Solution.

Hey AndGar,
by trying I found one chanel on the platine with give me an trigger signal. So I can measure something but not in every chanal.
Maybe just the PFI x- ports are reserved for triggering and you need to close every other task which measures a digital signal.
*actuall I have no access to the programm*
Thanks and best regards,
Marcus

How to sync. 50Hz sample rate with 5Hz external digital trigger signal?

Hello there,
I want to sample an analog input at 50Hz, where I further want to use
the 5Hz PPS signal of a GPS receiver as an external trigger/clock
signal for the NI DAQ USB-6008 device. However, I do not want to read
10 samples every 200ms (= 50Hz avg. sample rate), but I want to read 1
sample every 20ms, i.e. with "real" 50Hz.
The "natural" way, it seems would be to use a task that waits for a
rising edge on the ext. trigger input, then reads 10 samples, then
waits for the next trigger edge, and so on.
However, it seems that with this approach I cannot read the data from
the DAQ with real 50Hz, further it seems that every 10 samples the task
needs to be restarted, which takes longer than the 20ms (corresponding
to the 50Hz target sample rate).
I hope the problem description is clear enough....
Thank you in advance for any advice.
Regards,
Oliver

You have to use the counter together with the analog input to achive this. You could configure the counter to generate 10 pulses with 50 Hz whenever the counter sees a rising edge on the inpput of the counter. The output of the counter would be used as the external clock for the analog input.

Analog output digital start trigger c api

Hi, I am attempting to start analog output based off a digital trigger (either PFIO, or a PXI line) I can do this easy in LabVIEW. However with the C API (through Python wrappers), the problem isthat when I call DAQmxBaseWriteAnalogF64, the write will always timeout as the acquisition has not been triggered. However, I cannot call this after the trigger occurs, as obviously that will be too late.
I cannot find any C API examples where analog output is triggered off a digital trigger. I can find them for analog input, but that is fundamentally different as you can performan read anytime after the trigger occurs.
Python code as follows (the functions are equivalent ot C API, though you do not need ot pass the task handle as it maintained as part of the Task object)
# create analog output task
analog_output = Task()
analog_output.CreateAOVoltageChan("Dev1/ao0","",-10.0,10.0, DAQmx_Val_Volts, None)
analog_output.CfgSampClkTiming("",outputRate, DAQmx_Val_Rising, DAQmx_Val_FiniteSamps, numSamples)
analog_output.CfgDigEdgeStartTrig("/Dev1/PFI0", DAQmx_Val_Rising)
analog_output.StartTask()
analog_output.WriteAnalogF64(numSampsPerChan=numSamples, autoStart=False,timeout=1.0, dataLayout=DAQmx_Val_GroupByChannel, writeArray=data, reserved=None, sampsPerChanWritten=byref(samplesWritten))
print("Analog output: Wrote %d samples" % samplesWritten.value)
# create digital trigger
dig_out = Task()
dig_out.CreateDOChan("Dev1/port0", "", DAQmx_Val_ChanForAllLines)
# create digital trigger function
highSamples = 1000
numpts = 3 * highSamples
doData = np.zeros((numpts,), dtype=np.uint32)
doData[highSamples:2*highSamples] = 2**32 - 1
# send digital trigger
doSamplesWritten = c_int32()
dig_out.WriteDigitalU32(numSampsPerChan=numpts, autoStart=True, timeout=1.0, dataLayout=DAQmx_Val_GroupByChannel, writeArray=doData, reserved=None, sampsPerChanWritten=byref(doSamplesWritten))
print("Digital output: Wrote %d samples" % doSamplesWritten.value)

Hi PatrickR,
You can review some of the text based NI DAQmx (ANSI C) code examples on generating an analog output using a digital start trigger. If you included/checked text-based support dusing your NI DAQmx driver installation, you can navigate to Windows Start>All Programs>National Instruments>NI DAQ>Teaxt-Based Code Support>ANSI C Examples>Analog Out>Generate Voltage>Mult Volt Updates-Int Clk-Dig Start. If you have any questions/concerns regarding the NI hardware.

Multiple Channels with Single Digital Edge Trigger

I have a simple vi where two analog channels are read in and recorded simultaneously to a lvm file and plotted on a waveform graph. I need a digital edge to post trigger the data acquisition for both channels.
I can get this vi to work with one analog channel and the digital edge trigger just fine.
When I remove the digital edge trigger, I can get the vi to work with both analog channels. Both signals plot on a waveform graph, and record nicely in the lvm file.
The issue is how I am setting up the digital trigger (see attached). The program is never entering the while loop. Where am I going wrong?
Chassis:cDAQ-9172
Analog Card:NI 9205 (Trigger Source PFI0)
LabView: 8.6
OS: Windows XP
Solved!
Go to Solution.
Attachments:
Analog Input with Digital Edge Trigger.vi ‏52 KB

Gardma,
I am going to take a quick guess (I'm lazy and haven't actually tested the code ), but, since it works without the trigger and given that you have it so that the read never times out (i.e. = -1), there is something going on such that the trigger is never generated on the source pin. Just a thought.
Cheers, Matt
Matt Richardson
Certified LabVIEW Developer
MSR Consulting, LLC

Switching of analog measurment signals

Hello,
in our LabView applications we have to measure several voltages and
currents. We use a AT MIO 16 E 10 DAQ card, but it is not good enough
for 2 voltages 2 currents. Therefore, we use exernal GPIB measuring
instruments for them (Keithley 2000 a.a.).
However, I think we could come along with only one Keithley 2000 since
the timing is no issue (1 scan per sec is enough). I need some switch
controlled by LabView that switches the analog measuring signals to
two Keithley 2000 (analog) inputs (one for voltage, the other for
current measurement, respectively).
I found out that I can't do this with the DAQ card alone. I can't use
the analog outputs since I don't want a A/D - D/A conversion included.
Note that the measuring volta
ges can be ~100 mV.
But I could be wrong since I am actually a software guy so please
correct me if this is possible with the DAQ card only.
My idea is as follows:
I could use the digital outputs of the DAQ card and connect them to
some opto coupler or relais with TTL input. The opto couplers or
relais would switch the analog measuring signals according to the
digital outputs of the DAQ card and finally according to LabView.
I couldn't find such a switcher board in the NI catalog. They have
switchers, but they seem to switch voltages >3V only. But maybe
someone suggests a board from another company which suits better.
I just wouldn't like so much soldering my own board since my knowlege
of opto couplers, relais and hardware in general is really limited.
Best regards
Johannes

Hi Marcus,
thanks for your answer.
I was probably not clear about what I want. The solutions you suggest
seem to be far to complex. As Nirmal pointed out, I actually only need
high quality optocouplers, no more.
On Thu, 25 Mar 2004 09:30:26 -0600 (CST), Marcus G wrote:
>Hello Johannes,
>It sounds like you're setting up a system that requires four analog
>inputs (two voltage and two current), and you would like to use an
>analog trigger to switch between which signals are measured.
No. I just want to use the digital outputs of the DAQ card to switch
optocouplers. The optocouplers will switch between several analog
measuring signals. They should route these signals to one analog input
of a Keithley 2000.
>There are
>several options of
how you can set up such a system.
>In terms of measuring the four analog inputs, you should be able to do
>this with a DAQ card alone. Many of our cards, including the
>AT-MIO-16E-10 (also called a 6020E), have 16 analog input channels
>that have an input range of +/-10V.
I don't want to measure the four analog inputs with the DAQ card since
it isn't precise enough. The input range is too high for some of the
analog inputs and the resolution is too low. Also, I can't modify the
input range of the DAQ card at runtime. Therfore, we are using
external instruments (Keithley 2000 a.a.) for the measurements. My
idea was to only use one instrument for the four analog input signals.
Then I must provide the switching between the four analog inputs. The
idea was to control (switch) some optocouplers with the digital
outputs of the DAQ card. The optocouplers should route one of the four
analog signals to one Keithley 2000. I set the digital outputs of the
DAQ card in the LabView program. Also, t
he LabView program configures
the Keithley 2000 and reads the measuring values from the GPIB. That's
all.
Regards
Johannes

Does "pause trigger" have a status flag?

Hi,
I am using a BNC2110 with PCI6133 multifunction DAQ card. I am reading random analog voltage pulses on one channel for now, and using the "Pause Trigger" properties (on trigger property node) so that the read task only takes in samples from the pulses, and not samples of the baseline noise between pulses. This works ok. But is there a way of signalling when the pause trigger has actually started and stopped (at the rising and falling edges of a pulse, respectively)? I want to use these signals to index the collected data so that I know where in the data any one pulse starts and ends, and so keep all pulse data separate, but in one array.
Many thanks,
Oliver.

Hi Oliver
One thing you could do it to look for a timeout error to flag when a pause occurs. The time-out error code is -200284. If you set the timeout value to the minimum (1) you can keep checking for the timeout and set a boolean to true when a timeout occurs. So if the boolean is true you know you have a pause, if the boolean is false you know you are reading in the signal.
I have adapted the vi that you posted to do this and attached it below.
I hope this helps
Thanks
Beejal S
NI UK & Ireland
Attachments:
ai_with_analog_pause_trigger_flag.vi ‏44 KB

Does Mini Displayport to DVI adapter support analog VGA signal?

I'm just about to buy a macbook pro. Since the MDP (mini displayport) to DVI and MDP to VGA adapters are £20 a pop, I can only afford to get one. Obviously DVI is better in general, but VGA supports more older hardware, CRTs, and the spare VGA input on one of my displays (where the desktop uses the DVI).
What I'd like to know is does the MDP to DVI adapter also support the analog VGA signal on certain pins (like most physical desktop DVI ports do)? If it does, since I have about 3 or 4 DVI to VGA adapters lying around, I can get the MDP to DVI adapter and use the DVI to VGA adapters with it if necessary, but if it doesn't I might be better off getting the MDP to VGA...

No. Unlike DVI, which in the DVI-I configuration has both digital and analog pinouts, DisplayPort (and mini-DisplayPort) are purely digital. Mini-DP to DVI then DVI to VGA will not work. If you look carefully at the Apple Mini-DisplayPort to DVI adapter, you'll notice it's a DVI-D connector - digital pins only.
The Apple mini-DisplayPort to VGA adapter contains a digital-to-analog converter.
So, you'll have to choose. If you want VGA, get Apple's mini-DisplayPort to VGA adapter.

Analog Audio Output Jack for Digital Speakers with same jack configuration

I just purchased my first Mac, a Mac Pro. I can't get sound to my speakers using the analog out jack. With my old PC, there was a setting for "digital output" even though the digital speakers were attached via to the same style jack as the Mac's analog out jack. I've tried going to preferences but don't see a like setting for digital output. Is there a setting to do so and if not, is there an adapter to convert the Mac's digital audio out to the analog jack style?

Do you want digital or analog? Your question seems to imply that you have speakers that accept a digital signal but you also say you want analog...??
Anyway, my Mac Pro (2006 model) has separate analog and optical digital outputs on the back. The pictures on the apple website still show the same thing on the Mac Pro so I'm guessing it's the same. I think only the Mac laptops have the analog/optical digital combo jacks...
The optical digital outputs are the little white squarish ports beneath the rear firewire ports.
The MacPro does not have a SPDIF RCA style output. Maybe that is what you are thinking of from the windoze pc...
You should be able to enable the rear analog line output or the digital outputs from the System Preferences > Sound > Output screen. The front headphone outputs kind of act weird in that they disable the rear line output (if I remember correctly, I never use the front port...).

Question about pause trigger: multiple triggersources

Hello,
I have two digital signals which I want to use as source for pause triggering. The pause triggering is done with a triggernode. The problem I have is that I can add two sources to the node but it won't react on both, just one. So I guess it only accepts one signal. The first triggersignal will start the logging for an unknown period of time. When the first triggersignal drops, the second trigger signal will follow immediately and will continue for 5 seconds. Maybe there is no need to add a second trigger source because the time the signal has to be logged is known and follows directly after the first trigger signal. But I can't seem to find a solution for that.
Another problem I have is that I'm logging at a rate of 100 Hz but on my excel file I find only 500 samples after 10 seconds of logging. Im logging the signals from 2 NI9237's and a NI9219. The rate from the NI9237 is 2000 Hz but I decimate it to 100 samples per second. The signals from the NI9219 are logged at 100 Hz and are untouched.
Thank you
Solved!
Go to Solution.
Attachments:
Prog.7z ‏138 KB

Thanks for letting us know it is solved. i will close the call at our end.
Regards,
Rik Prins, CLD
Applications Engineering Specialist Northern Europe, National Instruments
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Digital stimulus-frequency response: Need to drive with digital output trigger. Using counters for response.

I need to drive stimulus-response with a software driven digital trigger and NI-TIO counter based response. No analog I/O is really relevant, although I have a PCI-6035E multi-function DAQ as part of my gear. I intend to use the analog, but its timing is non-critical and can be software timed.
The real trick is that I want to set the basic timing of the system (in the range of 1 - 50Hz) from the timer0 on the 6035E. This signal needs to be replicated to drive a trigger pulse and to route through RTSI (or a PFI) to trigger frequency counts using the four possible groups of counter/timers on the 6602.
What I need is:
while( enabled )
Repeat at (
software controllable rate = 1-50Hz)
Trigger Sets a PFI line for 10-20us
same trigger sets an RTSI line
- Software Set Delay (usually zero)- stable is more important than the delay time!
Count for software set time on 4 counters
analog samples
Post-process
I want to do this in LabView. I have checked out the Advanced sychronization demos online, but the examples all use analog triggering and buffered digital I/O. This doesn't really address what I need to do.
I have made some failed attempts which relied on software to sync up the trigger and the response frequency acquisition. This is definately flawed. I need to start the counting right after setting the digital output trigger, and stop the count after a fixed interval for frequency calculation.
I am having trouble working through the signal routing to get the timing to trigger off the digital stimulus output pulse.
Any help would be appreciated
Thanks,
Joe

Joe
What are you using the trigger from the 6035E for? I do not know what you mean by, "to trigger frequency countes."
If you are having problems just routing the signal to the 6602, here is a vi that shows you how to route a signal through the RTSI cable to use as the source of a counter.
Brian
Attachments:
Route_RTSI_to_Source.vi ‏67 KB

External signal gated measurement

Hi,
I have a PCI-6602 card and use it in LabVIEW 8.2 with DAQmx.
I use an external digital signal as trigger to PFI0 channel (choose pause when low option),
and using ctr0 for the source signal channel.
The problem is: the external trigger signal contains three parts: 1 ms high voltage, 3 ms low votage,
1 ms high voltage, I want to get the counts for first 1 ms duration and the second 1 ms duration, how to do it? Thanks.

Hi JackN,
It sounds to me that you simply want to make a pulse width measurement using your counter. This is no problem. If you go into the example finder Help>>Find Examples... The browse to the path Hardware Input and Output>>DAQmx>>Counter Measurements>>Period or Pulse Width and find the example Meas Pulse Width-Buffered Finite.vi. You can simply use this VI which will give you a measurement of the that 1ms pulse width in either seconds or ticks of the source signal. You will want to connect your "trigger" signal (1ms-3ms-1ms) to the gate of the counter you're going to use. Then if you have an external sample clock to make this measurement you'll connect it to the source of the counter, other wise do not connect anything else and use implicit timing on the DAQmx Timing.vi. If you are using an external sample clock to make this pulse width measurement you might also want to check out the VI just below the one I mentioned that also includes ...Sample Clock... in the name.
Using this VI will give you the pulse width of both of the 1ms pulses and if you keep it as a finite acquisition you'll only need to take 2 measurements. So in this case you don't really need to think of the signal as a trigger but as the signal that you're actually measuring. If you're curious about the capabilities of the counters in your 6602 take a look at the M Series User Manual in the Counters section starting on page 107.
http://digital.ni.com/manuals.nsf/websearch/2025C99AB0614F9E8625748000577B9A
Chris W

Read analog trigger signal gated by digital pause trigger

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