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LDmicro Forum - LOW RPM HOW TO MEASURE ?

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LOW RPM HOW TO MEASURE ? (by QURESHI)
DEAR
PLEASE HELP ME ABOUT LOW RPM METER
I WANT TO LOW PULSE TIME MEASURING IN ROUND / MINUTE
EXPLANATION:

60 SECOND DIVIDED BY 1 PULSE = 60 RPM MEAN OUTPUT DISPLAY

60 SECOND DIVIDED BY 2 PULSE = 30 RPM OUTPUT DISPLAY

60 SECOND DIVIDED BY 60 PULSE = 1 RPM OUTPUT DISPLAY

HOW CAN I MEASURING ? I TRY TO MEASURE BUT NOT RESULT ACCURATE I NEED DISPLAY 00.0 RPM
FOR MEASURE WITHIN 3 TO 5 SECOND MAXIMUM TIME
HOW I CAN ?
THANK TO HELP ME IN PIC16F877A *.ld
Sun Jan 17 2010, 06:46:18
(no subject) (by Jonathan Westhues)
What kind of sensor are you using to measure? A normal encoder would generate one (or more) pulse per revolution. So by counting the number of pulses in one minute, you would have the speed in RPM; but that's the reciprocal of what you write above.
Sun Jan 17 2010, 12:19:19
(no subject) (by David R)
Hi,
I think I understand,
Ldmicro can not calculate decimal point.

You will need to encode 10 or more pulse per revelation and
count them and display it as 300 (is equal to 30.0 rpm)

you could split out the last zero and produce it as A separate number and print it after A point.

Remember the input pulse needs to be slower than the scan time of the chip.

Hope this helps
Regards
David.
Mon Jan 18 2010, 04:53:17
(no subject) (by QURESHI)
DEAR Jonathan Westhues and David R

THANK TO REPLY ME and try to solve my problem

RPM MEAN ROUND PER MINUTES

METAL DETECTOR SENSOR TO PROVIDE ONE PULSE , NO ENCODER USED

1st PULSE TO 2nd PULSE BETWEEN TIME MEASURING WIDTH CALCULATION MEAN
FOR EXAMPLE:

1st PULSE TO 2nd PULSE WIDTH MEASURING SUPPOSED

1ST TO SEE ATTACHMENT
NEED WHEN TIME INCREASE THEN RPM SHOW DISPLAY LOW 1 RPM
NEED WHEN TIME DECREASE THEN RPM SHOW DISPLAY HI 60 RPM

PLEASE SOLVE THIS PROBLEM THANK TO YOU SEND ME IN (FILE LDMICRO)
Mon Jan 18 2010, 14:02:45, download attachment mpm.JPG
(no subject) (by MGP)
1 pulse per revolution is not enough
You can not measure 1 rpm in 5 seconds, you'll need at least 60 sec.
A timer and a counter will do the job

If you want to display the measurement every 5sec. The minimum speed in this case = 20 rpm.

If you want a faster reading than every 60sec, you need at least [display time = 60 / pulses per revolution].
Tue Jan 19 2010, 14:43:11
Example low RPM counter (by MGP)
Attached an RPM counter.
How to dislay it, is your problem ;-)
Wed Jan 20 2010, 15:48:29, download attachment RPM_counter.ld
(no subject) (by MGP)
Your welcome.

You can always contact me on this forum.

I live in Belgium (Brussels), so Pakistan is to far for me ;-) , Nevertheless, thanks for the offer.

Regards
Fri Jan 22 2010, 06:00:12
RPM Counter (by SocialMyth)
Hi MGP! I can't open the RPM_counter.ld file you attached, do you happen to have another copy?
Wed Apr 18 2012, 16:05:12
RPM_counter.ld is ok file (by MFQ)
my computer easily download and open in it
whats problem in your downloading ?
Fri Apr 20 2012, 03:58:43, download attachment RPM_counter.ld
When enough rpm led on. (by Razi)
Hi Mr how to on led .. example I want on led at 6000 rpm can help me?
Tue Dec 29 2015, 12:04:35
(no subject) (by MGP)
I have slightly modified the program for reading higher engine speeds.
Wed Dec 30 2015, 08:30:59, download attachment RPM_counter _version2.ld
(no subject) (by Razi)
I will try to thank you sir
Fri Jan 1 2016, 20:52:23
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