Event triggering TTL signal
I have written a program in flash for a decision-making paradigm to be used in psychological research. I am now needing to have a TTL digital signal output to an external psychophysiology recording device in response to specific events (e.g., button press, or presentation of specific images, etc.). I have seen a couple posts related to this question, but with no solution offered. Has anyone done something like this before - and if so, can you tell me how??
What is the nature of the device producing the TTL trigger signal? Is it possible, for example, that it could produce a 1-microsecond pulse (that might not be visible on your plot of the signal) that would trigger the counter? Are you really producing a digital pulse (i.e. is your circuit something that is either "on" or "off", as opposed to "produces an analog voltage in the range 0 to 5 volts")? Are there other devices around that could be producing pulses that are being "picked up" by your counter? Is the cable connecting the TTL pulses to the counter shielded? Is the shield grounded at only one end?
These questions (and the previous one) suggest that the problem may be "electronics" rather than "LabVIEW" ...
Similar Messages
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PXI-2514 triggering with TTL signal
Hello,
I'm looking for help regarding opening and closing of the individual relay on PXI-2514 card through use of TTL signal.
I'll appreciate any help.
And, as this is my first post - hello everyone, I'm glad to be hereHello, and thank you for your reply.
I'll try to describe it in detail.
I have a PXI with two cards pxi-6115 and pxi-2514.
Using pxi-6115 digital output I've generated a set of two impulses, and first one triggers pfi0 of pxi-6115 and through it aquisition of AI0.
I wanted the signal on pfi0 of pxi-6115 to trigger pxi-2514 at the same time to close the relay (channels ch0 and dut0) and the second impulse (which does nothing to AI0 aquisition) to open the relay (disconnect ch0 and dut0). As I've mentioned this digital signal is connected to pfi0 of pxi-6115.
I tried to route that signal to pxi-2514 ttl0, but with no luck.
I attach png files with my test solutions.
Best regards -
TTL signal vs TCP-IP, parctical and timing considerations
We have just purchased a BioPac MP1 50 physiological recording system (www.biopac.com). We would like to start/stop an acquisition from another computer system and/or to add annotations and markers.
To this end it seems there are two routes to consider. We could either use the built-in Trigger in/out capability with TTL signal of (0 and +5V square pulse) or use TCP-IP client-server to control it remotely (i.e. using VIs such as TCP-IP Listen). In the later case, I�d use the Beta LabView API libraries that BioPac is about to release for the MP150, instead of the dedicated AcqKnowledge 3.8.1 software, which is really good.
Because we need to correlate event during the physiological recording of our experim
ent, it would be ideal if the resolution were of ms accuracy (i.e. latency less than 1ms) and we need to manage up to 16 trigger channels.
I have very little technical background knowledge on this. Thus, in order to help me evaluate a solution, I would appreciate any comments and suggestions.
1) I would like to know first if anyone could recommend an easy solution to generate TTL signal (0 � 5V logical pulse) on both Windows and LINUX PC?
For instance I read about using the 25-pin parallel port, but I am curious to learn about other possible alternative such as USB, USB2 with or without adapter but also a very cheap card (a couple $100 max). I am already ruling out serial connection, because I am told it is very slow and has horrendous latency.
2) What are the latencies in read and writing/issuing TTL signals com? How does it compare with a dedicated byte stream through TCP-IP, on a dedicated cable and on a network cable?
3) Are they any VI application that you c
ould share to show how LabView 7.0 can talk through the respective ports to generate a pulse forming the trigger information being written or read in?
I look forward to hearing your feedback and suggestions. Many thanks in advance.
Donat-Pierre LUIGIUse TTL. It is likely that the TCP/IP messages will get there fast enough
and that the software will respond in a timely manner but there is no way to
be sure. It is the fastest way to get from your LV application to your
other device. You may need to check the response time that the BioPac will
give to the TTL input verses a TCP/IP message.
You should also consider the level of programming needed to accomplish your
tasks. I would strongly suggest that you get a seasoned LV programmer on
the job or you will be wasting a lot of time and enduring needless
frustration.
The parallel port will respond is sub-millisecond. You should be able to
toggle it several hundred times in a millisecond. I've had LV applications
use the printer port for this type of communications before. I don't
remember the bandwidth but it's more than adequate for this application.
TCP/IP will sometimes get delayed by the OS (either Windows or Linux) due to
other things that are happening at the time which you don't have control of.
The message should go out in very short order (again sub-millisecond) but
there is no control over this.
Good luck,
Chuck
"Donat-Pierre" wrote in message
news:[email protected]...
We have just purchased a BioPac MP1 50 physiological recording system
(www.biopac.com). We would like to start/stop an acquisition from
another computer system and/or to add annotations and markers.
To this end it seems there are two routes to consider. We could
either use the built-in Trigger in/out capability with TTL signal of
(0 and +5V square pulse) or use TCP-IP client-server to control it
remotely (i.e. using VIs such as TCP-IP Listen). In the later case,
I'd use the Beta LabView API libraries that BioPac is about to release
for the MP150, instead of the dedicated AcqKnowledge 3.8.1 software,
which is really good.
Because we need to correlate event during the physiological recording
of our experiment, it would be ideal if the resolution were of ms
accuracy (i.e. latency less than 1ms) and we need to manage up to 16
trigger channels.
I have very little technical background knowledge on this. Thus, in
order to help me evaluate a solution, I would appreciate any comments
and suggestions.
1) I would like to know first if anyone could recommend an easy
solution to generate TTL signal (0 - 5V logical pulse) on both Windows
and LINUX PC?
For instance I read about using the 25-pin parallel port, but I am
curious to learn about other possible alternative such as USB, USB2
with or without adapter but also a very cheap card (a couple $100
max). I am already ruling out serial connection, because I am told it
is very slow and has horrendous latency.
2) What are the latencies in read and writing/issuing TTL signals
com? How does it compare with a dedicated byte stream through TCP-IP,
on a dedicated cable and on a network cable?
3) Are they any VI application that you could share to show how
LabView 7.0 can talk through the respective ports to generate a pulse
forming the trigger information being written or read in?
I look forward to hearing your feedback and suggestions. Many thanks
in advance.
Donat-Pierre LUIGI -
Fast speed TTL signal sampling
Hi,
I am a beginner of Labview. Currently we are facing a new project that i believe fast data acquisition is the key point. If someone could give some guidance I would be greatly appreciated.
Board: AT-MIO-16E1
Signals: A series of TTL signals generated by an avalanche photodiode, 30 nanoseconds in width, the frequency of the occurence of signals could be as high as 10MHz.
Objective: Counting the number of TTL signals during a certain period of time, (form microseconds to milliseconds) store it somewhere, and repeat the counting and storing precedure for lots of cycles as many as the hardware allows.
Questions:
1. Is this a project for the board and Labview software?
2. As we imaging, there will be some deadtime tween th
e periods that the signals are being counted. Could we minimize the deadtime to a insignifcant value? (like 5% of the counting time?)
3. If it could be done by Labview, is there any additioal hardware we need to purchase? E.g. a board that provides gating signals.
4. Is there any exsisting examples we can copy?
Thank you,
GufengBeing a long time user of the E1 boards myself, I would say that you MAY be able to do this. As I don't have the specs handy right now, I can suggest a means by which to come up with the solution for yourself:
Check the specs of the board. You are looking for the specs for the DAQ STC timer portion, as you want to do counting operations, not data acquisition. I don't remember if the DAQ STC on the E1 can handle 10MHz. If it doesn't, stop there, and get your NI Catalog and look for one of the newer boards with the advanced timing chips, I believe these can handle it. If the E1 can handle it, go on from there. Create a timing diagram for yourself, to get a visual picture of what you need. Then determine what gating and triggering you need. There are numerous
examples in the sample programs database in LabVIEW for counting. These should point you in the right direction.
Good luck -
TTL signal count problem: mistaken counting
Hello,
I use a 0.2Hz TTL signal to synchronize two devices. I use a Usb 6210 card to count the TTL pulse. The counter is triggered when it detects rising edges. In my case, the counter was sometimes triggered at low level, which causes a false result (see the attached images, the TTL signal is sampled at 20Hz and the dots represent an increment of counter). How can I resolve this problem?
In addition, the cable which connects the TTL output was welded by myself, could it be a problem of poor contact?
Thanks a lot,
KX
Solved!
Go to Solution.
Attachments:
pb_ttl1.jpg 80 KB
pb_ttl2.jpg 223 KBWhat is the nature of the device producing the TTL trigger signal? Is it possible, for example, that it could produce a 1-microsecond pulse (that might not be visible on your plot of the signal) that would trigger the counter? Are you really producing a digital pulse (i.e. is your circuit something that is either "on" or "off", as opposed to "produces an analog voltage in the range 0 to 5 volts")? Are there other devices around that could be producing pulses that are being "picked up" by your counter? Is the cable connecting the TTL pulses to the counter shielded? Is the shield grounded at only one end?
These questions (and the previous one) suggest that the problem may be "electronics" rather than "LabVIEW" ... -
How to disable the "turn page" event triggered by the scroll/swipe function?
The problem is as follows.
The default behaviour of Acrobat Reader (both stand alone and browser plug-in) is to allow scrolling/swiping with the mouse wheel/trackpad. This is useful when the pdf's page length is greater than the screen's own length, because you can read the pdf with no need to distract your attention from the text to the scrollbar button. However, the same scroll/swipe function turns into a usability problem when the pdf is embedded in a html page and the pdf's page length is smaller than the browser's length. In this case, the scroll/swipe turns the page, distracting your attention from the text to the unintended behaviour of the browser. What happens is that you are so used to scrolling/swiping that you did it unintentionally in the pdf's caption area. You really did not want to turn pages in the pdf. Furthermore, if the pdf takes the whole html page, being a website, the scroll/swipe function flips the website pages in ways that neither the reader nor the writer had ever intended. Hence the question. How to disable, in this case, the "turn page" event triggered by the scroll/swipe function? A JavaScript should do, but the SDK documents did not help so far...
Message was edited by: 41457173
Message was edited by: 41457173... or release a patch for the API,
... or suggest an alternative route to achieve the intended result. -
Event triggering by abap class & ISR
hi gurus
1 ) can i able to see the event triggering by abap class in SWEL ? ,
2) in custom ISR scenario , new form scenario has been created by our functional consultant , and asking me to trigger a workflow for approval , when employee fills that particular ISR FORM , workflow should start and to go his HR administrator , when HR administrator double click on workitem he should get the ISR form in display mode & also with some descpition text is to be added in the screen (like user decision description ) with approval button ..... my question is how to trigger a event from in form scenario ? , how to bring the FORM screen to display mode to the HR administrator ?
regards
suryaHi Surya
The BO for ISR forms is BUS7051 - Notification. Turn on the trace via SWELS and create a PCR/ISR form and you should see the events being triggered in SWEL.
Good Luck
Ravi -
Event triggered for checkbox in cl_gui_alv_grid
Hi All ,
I have a requirement like ,i give PO number on selection-screen.After execution, the items should be displayed on second screen ,which has some options on the top like before GR or after GR .(custom screen designed with cl_gui_alv_grid for display)
I desgined checkboxes for each row of the line item.user can click on multiple rows and click on EXECUTE button on the screen.After that smartform should trigger and print .
Now my query is how to capture the checkboxes which the user has entered (thru cl_gui_alv_grid) . Is there any event that gets triggered upon clicking the checkboxes?? I need the data of the corresponding row to process further .User can click on multiple items.
Please respond
ThanksHi Hemanth
You should have a field in your internal table matching the checkbox column in ALV.
Call method CHECK_CHANGED_DATA of CL_GUI_ALV_GRID on user command for execute button,
it will set the field = 'X' for ticked lines in your internal table.
Then use a loop on your internal table and find selected lines.
You don't need an event triggered when user clicks.
Edited by: Bulent Balci on Aug 3, 2010 4:42 PM -
How to send a ttl signal with a good exactitude less than 10ms?
i have a pci 6013 (8 input channel) and pci 6711 (4 outpout channel).Then i need to send a ttl signal to a camera ccd to take a photo when a waveform sinus is equal at zero (rising), but when i send this TTl signal with dasylab using generator pulse or combi trigger and readind this signal, i have difference between dasylab pulse(that is exactly) and measurement pulse that is approximate 40ms after.But i need to have less than 10ms is it possible?
Frequence rate =1000hz and block size=512 the waveform sinus is 0.2Hz.i have already try to increase the sampling rate but nothing happens.Thank for your help.Yes, it's possible.
You just have to reduce your block size to 10 !
For more informations, visit Forum Dasylab en français at http://forum.aceboard.net/?login=128657
Frédéric Miqueau
MD Electronic, France
http://www.mdelectronic.fr
French Dasylab Forum : http://www.dasylab-forum.de/forum/index.php?showforum=43 -
Bug in scrollbar event triggering?
In LabVIEW 8.6, I am trying to fire an event when I finish moving the scrollbar of an array indicator. I use the "mouse up" event to avoid having the event structure fire constantly the entire time I am moving the scrollbar. However, there seems to be a bug (?) in the event detection. It works fine as long as I have the mouse on top of the scrollbar when I release it. However, Win XP allows you to continue to move the scrollbar even if the mouse is off to the left or right of the bar (when you click on the scrollbar it "locks" the focus onto it). However, LabVIEW does not seem to realize this and if I have the mouse slightly off to the right of the scrollbar when I release, the event doesnt fire. LV seems to base the event off of whether the mouse is on top of the pixels of the indicator rather than whether I still have control of the scrollbar.
Technically it is not a bug. There is no event triggered because when you do the Mouse Up, you are no longer on the scrollbar. Unfortunately, the behavior in Windows that allows you to continue to move the scrollbar even when you aren't on it is conflicting with the desire to detect when you let go of the scroll bar.
There was a recent thread discussingthis very issue and a way to get the behavior you are looking for.
Re: Handle mouse up on numeric slider control - even when mouse leaves control -
How to realize the other three events triggered by a sequence of events occurs?
How to realize the other three events triggered by a sequence of events that occurs between Labview, and the time interval between three events for the 50ms?
1110340053Are you another student who feels the need to post their "student ID" number as a part of the message? There is really no need to do that, it is meaningless to us.
You should ask your instructor to answer your questions rather than allowing them to turn the whole class of students loose on the forums usually asking the same identical question.
At least in your case, the question is different from most we've seen. Unfortunately, you haven't asked a clear enough question for us to understand what you are talking about.
What "events" are you talking about? Post a VI that demonstrates the code that you have written so far. -
Event Triggers not getting executed
I'm having following code in beforeData(PLSQL) event trigger:
ADCPackageName.MethodName
There is no such package in database, even my report works fine and publish data without any error.
Is there any configuration for enabling event triggers.
I didn't sufficient documents on event triggers. I want to use them for returning some values to report variables and validating input parameters.Hi,
I tried to use "SAP_WAPI_CREATE_EVENT" also but it is also behaving in the same manner.
At first execution event is getting triggered but my workitem is not getting terminated.
But when i am executing the same report second time, again my event is getting triggered, and this time my workitem got terminated, and workflow proceeded furthur.
I checked it from SWEL, i have two entries for my event (i.e; first and second execution of report).
Any idea why it is behaving like this.
Please find below code for reference, apart from below code i have only declarations.
call function 'SWC_ELEMENT_SET'
EXPORTING
element = 'ActualState'
field = 'A'
TABLES
container = it_cont
EXCEPTIONS
type_conflict = 1
others = 2.
CALL FUNCTION 'SWE_EVENT_CREATE'
EXPORTING
OBJTYPE = 'WORKINGWI'
OBJKEY = '000000003061'
EVENT = 'Approve'
IMPORTING
EVENT_ID = it_event_id
RECEIVER_COUNT =
TABLES
EVENT_CONTAINER = it_cont
EXCEPTIONS
OBJTYPE_NOT_FOUND = 1
OTHERS = 2
COMMIT WORK.
Regards,
Amar -
Strange ZEN logout event triggering
Strange ZEN logout event triggering
Hi!
ZCM 10.3.2, Windows XP/7, Novell Client installed, have a bundle associated to device and should be triggered at ZENworks logout. This all seems to work ok, in ordinary way. But, when user auth is ok with Novell Client (against eDir), but is not attached with DLU via ZEN and appear Windows Workstation login screen and user cancel this dialog and return to Novell Client login screen, then before mentioned bundle is triggered, in some unknown for me reason. Because there is no ZEN login, not speaking about logout. I have similar bundle set to trigger at user login ... it does not run same way. Also, don't see same behavior when bundle is set to run at user logout.
Any ideas?
Btw. this kind of cancelling login is seems to related to getting a'lot of Bundle.ItemCreationError's described in http://forums.novell.com/novell-prod...ionerrors.html.
More thanks, Alar.Originally Posted by NovAlf
Strange ZEN logout event triggering
Hi!
ZCM 10.3.2, Windows XP/7, Novell Client installed, have a bundle associated to device and should be triggered at ZENworks logout. This all seems to work ok, in ordinary way. But, when user auth is ok with Novell Client (against eDir), but is not attached with DLU via ZEN and appear Windows Workstation login screen and user cancel this dialog and return to Novell Client login screen, then before mentioned bundle is triggered, in some unknown for me reason. Because there is no ZEN login, not speaking about logout. I have similar bundle set to trigger at user login ... it does not run same way. Also, don't see same behavior when bundle is set to run at user logout.
Any ideas?
Btw. this kind of cancelling login is seems to related to getting a'lot of Bundle.ItemCreationError's described in http://forums.novell.com/novell-prod...ionerrors.html.
More thanks, Alar.
Hi Alar,
Do you have any update on you problem because I have the same issue and I am wondering if you found any way to bypass it??
I found another thread but no solution:
http://forums.novell.com/novell/nove...ter-login.html
Thank you in advance for your answer,
OAKFND
PS: Zen version is 11.1 -
How do I measure the period of one TTL signal and the delay until a second TTL signal?
Hi,
I have a PCI 6024E board, the SCB-68 terminal box and am running LabView 6.1. If needed I could install 7.1.
I have two Honeywell sensors (HOA7720) which each consist of an infrared transmitter and a infrared reciever. When the beam is broken they output 5V, when the beam is open it outputs 0V. These are sensing the presence of a hole in two discs passing thru the sensors.
So as disc 1 rotates the signal is 5V until the hole passes thru sensor 1, then it drops to 0V until the hole passes. Then it jumps back to 5 V.
Disc 2 is rotating at exactly the same RPM as disc 1 because they are coupled with a spring loaded coupling. There is a delay between the first hole passing thru sensor 1 and the second hole passing thru sensor 2. The delay increases with torque.
Using the oscilliscope function and connecting Signal1 and Signal2 to AIn0 and AIn1, I have verified that the TTL signals are there. So electrically everything is working. I just need to know how to measure the period and delay. I'm familiar with A/D, but not with counters/gates etc and I think that's what is required here.
The first measurement needed is RPM. Somehow I need to measure the period of the TTL signal.
The second measurement needed is the delay between the 1st falling edge and the 2nd falling edge.
I don't think it's possible to use the millisecond timer for anything, because the accuracy wouldn't be good enough. At 3600RPM the disc will spin 60 revs per second, or one every 17ms. A resolution of 17 samples per revolution is not good enough.
Help please!It worked!
I ended up figuring it out today. It's really simple. I went analog in to AIn14 and AIn15 which were free. Then the program does a multichannel scan of the signals (collects array of 2 waveforms), Signal 1 and Signal 2 at some scan rate. I used 100,000 S/s for 10,000 samples. Then I split the array into two separate waveforms. Then I did an edge detect on each one and it returns the position in the array where the falling edge occurs. The difference is the delay (after correcting for the scan rate), unless Sig2 comes first in which case the delay is the period - (or +) the difference
To find the period I used a subset of the Signal 1 waveform from the first falling edge on to the end of the waveform, then did the same edge detect except set the reset setting to true instead of false so it wouldn't detect the low signal which was now at the position 0 in the waveform. So it would ignore the initial low value, wait for it to go high, then detect the falling edge position.
Anyway, it works awesome, seems very accurate and gives very stable readings. 3600rpm no problem. It detects changes of one or two degrees in angular position, with a range from ~145 degrees to ~280 degrees -
Squence of events triggered in reports
Hi all,
Please specify squence of events trigger. When top-of-page event triggers? When end of selection event triggers
venkraaWhen u start the Report:
LOAD-OF-PROGRAM
INITIALIZATION
Before displayins Selection Screen:
AT SELECTION-SCREEN OUTPUT.
Before leaving Selection Screen:
AT SELECTION-SCREEN.
After processing Selection Screen when the List starts:
START-OF-SELECTION.
Before displaying the List .. After completing START-OF-SELECTION.
END-OF-SELECTION.
For Every page:
TOP-OF-PAGE .
END-OF-PAGE.
For more details check this link -
Events in Report
the top of page can put any where in the program..
end of selection is after selecting data means the population of data is done in the start-of-selection and no data is selected in the end of selection if you write select after the end of selection ...is of no use..
regards,
venkat
regards,
venkat .
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