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Anonymous Poster #1

300mm Length Measurement in 21 millisec

06/03/2011 5:45 AM

I want code in micro controller based on textile field , while motor rotating thread is passing through shaft at 21 millisec of shaft speed I have to find 300mm length of thread . I need clue for this program in embedded C
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JohnDG
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#1

Re: 300mm Length Measurement in 21 millisec

06/03/2011 7:38 AM

Please explain your requirements more clearly. English may not be your first language, but you should at least know that speed is not measured in milliseconds.

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RDGRNR
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#2
In reply to #1

Re: 300mm Length Measurement in 21 millisec

06/03/2011 12:14 PM

300MM in 21ms is quick, fast, and in a hurry. Oops, there it went!

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JohnDG
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#3
In reply to #2

Re: 300mm Length Measurement in 21 millisec

06/03/2011 6:47 PM

Oh ... I 'C' you've got it sorted out!

So how do we code it?

main()

{

if (time of last rev > (21ms + halfdeadband))

goabitfaster();

else

{

if (time of last rev < (21ms - halfdeadband))

goabitslower();

}

}

... or something like that. Haven't 'C'd for years.

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Anonymous Poster #1
#4
In reply to #1

Re: 300mm Length Measurement in 21 millisec

06/04/2011 2:32 AM

In textile industry the machine used for transferring thread from large bundle A1 to another cone B1 for particular weight it may be 1,000,000 meters. The motor speed is 2880 rpm per min. bundle A1 count is 40s and weight is 2 kg from this have to find length? By formula length is 136000 meter. For 2880 rpm length is 859104mm/min , for one revolution 0.2983m/min~300mm/min , length delivered for one revolution 298.3mm , for 136000 m length no of revolution produced is 455916.9 rpm, Motor speed per sec is 48 sec, time for one revolution is 0.020833sec ,For 2880 rpm length in sec is 14318mm/sec,in milli sec is 14.318 mm/milli sec, Time for 1 rev or for 300mm is 21millisec this are found through calculation.

For this I need embedded coding, sensor used here is yarn sensor
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67model
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#5
In reply to #4

Re: 300mm Length Measurement in 21 millisec

06/07/2011 6:21 AM
  1. It seems to me that diameter of spool A1 will vary as thread is taken off?
  2. It is not clear whether you want to time an interval of exactly 21 millisec or measure a time interval of 21 ms approx to determine the rotation rate.
  3. In any case, a mains driven motor will vary in speed about +/- 1% due to normal changes in Grid supply frequency.
  4. Are we dealing with a) rotation speed problem or b) revolution counting or c) a wish to measure actual thread length wound onto the cone B1??
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Anonymous Poster #1
#6
In reply to #5

Re: 300mm Length Measurement in 21 millisec

06/07/2011 11:03 AM

to measure actual thread length in cone B1. now i had one doubt motor used here is induction motor it produce noise and error using microcontroller it not possible to measure properly, and while using in industry temperature ll increases it ll be also an error and in coding what we r coding it ll give output ... is their any possibillities to get output using PLC for measuring thread length in cone B1?...
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67model
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#7
In reply to #6

Re: 300mm Length Measurement in 21 millisec

06/07/2011 11:56 AM

Grid frequency will move about from moment to moment.

For textile I would suppose Variable FREQUENCY drive with DC link and synchronous motor would be advantageous.

But for textiles I would think there are patents for mechanical solutions to this problem going back 200 years and electrical/electronic measures 50 years or more old.

Those patents will have more thought and experience in them than anything we can think about in a few minutes.
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