How to measure the rpm using NI 9411 and counters

How to calculate the rpm of a shaft using NI 9411 and counters?

http://forums.ni.com/t5/Signal-Conditioning/measuring-rpm-using-DAQ-device/m-p/2571131#M7353
Additionally, if you set it to read a degree instead of pulse, your calculation will change a bit, but I'll leave that to you.

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How to measure the distance using script

Hi
Is there any way to measure the distance of any photoshop document using the measure tool, by using the script. Given below the steps required by me. Hope i'm clear in my communications.
I searched the forums but couldnt find any suitable answers.
1.Open Photoshop document
2. Allow the user to draw the line using measure tool
3. alert the distance
Rgs
Anish

Michael L Hale wrote:
Sorry maybe I wasn't clear. If you want the angle reported by the script to match what would be reported if the user used the line tool you do need to make the path left to right.
That would only be half right as you can use the ruler measure tool from left to right and right to left a full 360 the angles reported will be in the range of 0 to +|-180 if you limit it to left to right the angle range will be from +90 to -90.
I understand your statement for "var ang = (180/Math.PI) * Math.atan2(o,a);" will only generate the angle for a right triangle 0 through 90.   That is why I wrote the sign was an indication of direction meaning up or down but the problem is that there are two -45 and two +45 the other directiom left or right is only known by the line tool user. I do not understand path points you use lineStart[1] < lineEnd[1]to find out up or down perhaps some other comparison can find out left or right and then adjust the angle if to the right by to the range from +|-90 to +|-180.
I think I did it now matches the line tool left to right or right to left the angle now matches the ruler measure tool when ruler unites is set to pixels
// enable double-clicking from Mac Finder or Windows Explorer
#target photoshop // this command only works in Photoshop CS2 and higher
// bring application forward for double-click events
app.bringToFront();
// ensure at least one document open
if (!documents.length) alert('There are no documents open.', 'No Document');
else {
          main(); // at least one document exists proceed
//                            main function                                  //
function main() {
          // declare local variables
          var orig_ruler_units = app.preferences.rulerUnits;
          app.preferences.rulerUnits = Units.PIXELS;          // Set the ruler units to PIXELS
          try { alert(measureLine(app.activeDocument.pathItems.getByName("Work Path"))); }
          // display error message if something goes wrong
          catch(e) { alert(e + ': on line ' + e.line, 'Script Error', true); }
          app.preferences.rulerUnits = orig_ruler_units;          // Reset units to original settings
//                           main function end                               //
//the code below is for the Line tool.
function measureLine(path){
          var res = new Array;
          var lineStart = path.subPathItems[0].pathPoints[0].anchor;
          var lineEnd = path.subPathItems[0].pathPoints[3].anchor;
          var a = Math.max(lineStart[0],lineEnd[0])-Math.min(lineStart[0],lineEnd[0]);
          var o = Math.max(lineStart[1],lineEnd[1])-Math.min(lineStart[1],lineEnd[1]);
          var c = Math.round(Math.sqrt((a*a)+(o*o)));
          //alert("Triangle Height = " + o + " Width = " + a + " Hypotenuse = " + c );
          res.push(c);
          var ang = (180/Math.PI) * Math.atan2(o,a);
          if(lineStart[0] > lineEnd[0]){//To the left
                    ang = 180-ang;
          if(lineStart[1] < lineEnd[1]){//Down
                    ang = -ang;
          res.push(ang);
          return res;
Message was edited by: JJMack

How to measure the pulse duration of a TTL signal using AI?

Hi there.
I would like to know how to measure the pulse duration of a TTL signal using an Analog input.
These TTL signals comes from an ultrasonic sensor's output. The pulse width of the signal is
proportional to the distance of the object the sensor detected.
I have tried using the example "Measure Pulse Width.vi" which uses a counter to measure the
pulse duration instead. It provides me with correct results.
However, i will like to know how can i do it using the AI instead.
I tried it by using the example "Acq&Graph Voltage-Int Clk.vi" which i modified by including a
timing and transistion measurement vi. Pulse duration was selected as the output. A graph indicator was also added at the output of the pulse duration to monitor the incoming TTL signals.
However, everytime the TTL signals was detected on the graph indicator, the numeric indicator always produce a "zero" reading.
I have attached my vi for your reference.
Can anybody advice me what i have done wrongly?
Regard.
Attachments:
Acq&Graph Voltage-Int Clkv1.vi ‏190 KB

Hi Paul,
Today i tried using 2 different methods to read the pulse duration of my sensor signal.
Both methods use "Acq&Graph Voltage-IntClk" vi as a guide.
Method1:
Add a filter vi(lowpass/bandpass) and a timing and transition measurements vi.
Pulse duration is selected as the output. With some numeric conversion, a centimeter
reading indicator was created. However, the reading always remains as "zero"
Method2:
Add a Mask and Limit Testing vi and a timing and transition measurements vi.
By adjusting my upper and lower limits, i manage to "filter" a single pulse out from the actual signal.
However, like the earlier case, the cm reading still remains at "zero"
I have attached both the methods resulted waveforms for your reference.
Are there anything that you can advice on?
Regard.
Attachments:
Results_Waveforms.doc ‏141 KB

How to measure the baseline of a noisy, pulsed signal

Hi
I am measuring the torque exerted by a large motor on a shaft using a load cell and lever arm. The shaft runs at approx 150 rpm. I have attached a drawing that shows the output I get. This is a test rig.
I have written some code that measures the maximum peak out of a group of approx 5 peaks and writes this to a shift register. This gives me an idea of the maximum torque "spike".
I also wish to measure the baseline torque (due to the bearings in the machine). Even when highly filtered (my noise filter is set to 49Hz) the signal exhibits this noise which is probably due to vibration in the system. The signal is zeroed when the motor is not running.
Does anyone have an ideas on how to measure the "baseline" torque? The large spike in torque prevents me from doing a running average. Can anyone think of a way of averaging just the noisy part of the signal to get an average value? I aim to to subtract the average baseline torque from the peak value to get an idea of the torque due to the event which causes
the spike.
Any help would be greatly appreciated.
Many thanks.
Attachments:
drawing of torque signal.gif ‏26 KB

Thanks for the reply. I understand what you are saying. However, I might have to modify my method for measuring the peaks if I choose to implement your idea. I have taken a screenshot of my "peak finder" code and attached it.
Bascially, the reset terminal is wired to a timer which outputs a pulse every few seconds. This resets the vi (a standard NI one I think) and sets the peak magnitude back to zero. This way, I am windowing the signal and measuring the maximum peak in every window. This is what I need to do.
So I could use a logical filter to feed data to the running average only if;
the amplitude of the signal is less than a certain threshold
and if the current value has similar low peaks either side of it
How would you construct the code to delay the evaluation so that the values in front and behind of the current data point can be analysed?
thanks again
Attachments:
peak_find_screenshot.jpg ‏45 KB

How to measure the frequency of a pulse being generated by a counter

Hi,
I am using labview 8.6 to generate 5 evenly spaced pulses for every 1 revolution of my shaft. However, I would also want to know the frequency of these pulses so I can determine the shaft speed. Since I am already generating the pulses using one of my counters, can I still tap into that or task another counter to measure the pulse frequency? If so, how? I have attached my code for generating the pulses and I am using an Ni 9401 module and an NI 9172 chassis. If someone can helo me modify the code to measure and tell me the pulse frequency as well, that would be really appreciated
Attachments:
autotrain2.vi ‏19 KB

You'd probably get a more coherent answer if you didn't bounce around from thread to thread so much...
How can I generate a pulse train from shaft encoder? (5/13)
pulse train from encoder (5/15)
how to measure rpm (5/20)
How to measure rpm using shaft encoder and labview (5/23)
This thread (also 5/23)
I see you ignored my suggestion from the other thread--Kevin's solution is good too but using an encoder task offers more noise immunity (I think this is probably the cause of the problem you reported on the other thread). You can fix it with digital filtering if you want to keep using a counter output instead of an encoder task. Noise during transitions is pretty common for a quadrature encoder.
A finite counter output task uses 2 counters on the 9172 (although you said 9174 earlier at one point--this wouldn't be the case on a 9174) so you wouldn't have one left to make your frequency measurement. With the solution you have now, you can change to continuous to free up a counter if you don't care about outputing an exact number of rotation's worth of pulses (I'm not sure if you do or not--I didn't read through all of the various threads relating to this application to find out).
For your actual question in this thread... Have you tried running one of the frequency measurement examples? From the code here I can't tell what you have tried (it just looks like a mangled version of the code Kevin gave to you in your other thread).
Best Regards,
John Passiak

How to measure the performance of sql query?

Hi Experts,
How to measure the performance, efficiency and cpu cost of a sql query?
What are all the measures available for an sql query?
How to identify i am writing optimal query?
I am using Oracle 9i...
It ll be useful for me to write efficient query....
Thanks & Regards

psram wrote:
Hi Experts,
How to measure the performance, efficiency and cpu cost of a sql query?
What are all the measures available for an sql query?
How to identify i am writing optimal query?
I am using Oracle 9i... You might want to start with a feature of SQL*Plus: The AUTOTRACE (TRACEONLY) option which executes your statement, fetches all records (if there is something to fetch) and shows you some basic statistics information, which include the number of logical I/Os performed, number of sorts etc.
This gives you an indication of the effectiveness of your statement, so that can check how many logical I/Os (and physical reads) had to be performed.
Note however that there are more things to consider, as you've already mentioned: The CPU bit is not included in these statistics, and the work performed by SQL workareas (e.g. by hash joins) is also credited only very limited (number of sorts), but e.g. it doesn't cover any writes to temporary segments due to sort or hash operations spilling to disk etc.
You can use the following approach to get a deeper understanding of the operations performed by each row source:
alter session set statistics_level=all;
alter session set timed_statistics = true;
select /* findme */ ... <your query here>
SELECT
         SUBSTR(LPAD(' ',DEPTH - 1)||OPERATION||' '||OBJECT_NAME,1,40) OPERATION,
         OBJECT_NAME,
         CARDINALITY,
         LAST_OUTPUT_ROWS,
         LAST_CR_BUFFER_GETS,
         LAST_DISK_READS,
         LAST_DISK_WRITES,
FROM     V$SQL_PLAN_STATISTICS_ALL P,
         (SELECT *
          FROM   (SELECT   *
                  FROM     V$SQL
                  WHERE    SQL_TEXT LIKE '%findme%'
                           AND SQL_TEXT NOT LIKE '%V$SQL%'
                           AND PARSING_USER_ID = SYS_CONTEXT('USERENV','CURRENT_USERID')
                  ORDER BY LAST_LOAD_TIME DESC)
          WHERE ROWNUM < 2) S
WHERE    S.HASH_VALUE = P.HASH_VALUE
         AND S.CHILD_NUMBER = P.CHILD_NUMBER
ORDER BY ID
/Check the V$SQL_PLAN_STATISTICS_ALL view for more statistics available. In 10g there is a convenient function DBMS_XPLAN.DISPLAY_CURSOR which can show this information with a single call, but in 9i you need to do it yourself.
Note that "statistics_level=all" adds a significant overhead to the processing, so use with care and only when required:
http://jonathanlewis.wordpress.com/2007/11/25/gather_plan_statistics/
http://jonathanlewis.wordpress.com/2007/04/26/heisenberg/
Regards,
Randolf
Oracle related stuff blog:
http://oracle-randolf.blogspot.com/
SQLTools++ for Oracle (Open source Oracle GUI for Windows):
http://www.sqltools-plusplus.org:7676/
http://sourceforge.net/projects/sqlt-pp/

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windows app store how to measure the size of a string?
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if you only need the "length" of the string i.e. no. of characters than use (see
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dont forget to bing / google :)
hope this helps!
Graphics.MeasureString(String, Font) can not use in windows store app.
TextBlock has Measure()
method, as following:
Size MeasureString(string content, Size availableSize, double fontSize, string fontFamily="Segoe UI")
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Re: Lifecycle Implementation
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In order to estimate the instance size, you will have to sum up all the instance variables size.
From the practical prospective it may be difficult to use the algorithm in cases when your instance variables are not simple types.
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You can write a simple program (either java or SQL plus) that would read the instance from the BLOB and measure the size.
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Whenever an exception is raised how to log the exception using Log action in oracle service bus.After logging where I have to find the logged message.

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How to measure the performance of Extractor

Hi,
How to measure the time taken to by the extractor when executed from rsa3 for a given selection?
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Fred

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If you want someone to do your work, please have the courtesy to provide payment.
http://www.rentacoder.com

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HI All,
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How to get the workcentres used in the routing out of 2 alternate routings

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HI,
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Edited by: Krishna Mohan N on Jan 31, 2008 12:28 PM

How to measure the size of a table ?

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How to measure the rpm using NI 9411 and counters

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