analogue frequency converter

[srd]

Is it possible to have a pulsed input from a water meter that pulses every 10litres and convert it to an anologue output so i can display the flow rate.

[radar17892]

Hi srd
You can do that, but important is the question: What is the range of frequency from your water meter?
You may use an frequency measure for signals gt 4Hz.
If not, take a counter in combination with timer (to count impulses in a gate time, after this time first write counter-QV into a DB,   zerosets the counter and start next gate time)
This is possible up to double cyclic time.
Now you can load DB- QV into LS- funktion to scale value for display the flow.

Regards Thomas

[srd]

Cheers Thomas i will try and give it a go. The Hz would have to be set depending on the job we were doing as the pump used is not always the same so on one job we cud use a pump that does 20cube an hour and on another job we could use one the only does 5cube an hour.

[radar17892]

Hi srd
here`s a little example for you.
I hope, this is what you need. Adjust with IA1 the frequency in simulation mode and look at QA1+Display!

Regards  Thomas

[srd]

Cheers Thomas i had a little play and it works spot on it's just i don't quite understand the parameters for AR01, AR02 and LS01 so that if i had to change from litres to say cube an hour. I can sort off understand what you are doing with AR01/02 and LS01 but i don't get where the figures come from for example on AR01 you have I1 as the data block and I2 as 600. Where do you get 600 from or am i being thick!!!

[Maikky]

Dear srd.

I assume that the parameters in the example of Thomas are a little mixed up.

In general you have to use the correction factor from
  - pulses within gate time (DB QV)
into
  - volume flow (display)

For the example
  - 1 pulse equaling 10 l
  - gate time 5s
you have to use the
   - parameter 2     for displaying l/s
   - parameter 120 for displaying l/min
   - parameter 7,2  for displaying m3/h

(factor = 10 l / 5s = 2 l/s = 120 l/min = 7,2 m3/h)

But you should think about your gate time. As far as I understood you are using a
20 m3/h or a 5 m3/h pump. With a 20 m3/h pump and a 10l-sensor you will get max.
2 pulses within 5 s. You can display full flow, half flow or no flow and that's it. With
the 5 m3/h pump it is even worse.

Regards
Maikky
 

 

[radar17892]

Hi srd,
I`m back now!
And with more comments on the blocks!  

water meter that pulses every 10litres and convert it to an anologue output so i can display the flow rate.

pump1 max.20m³/h = 2000pulses/h     LS block scals pulsrate for analog output->
parameter for LS block x1=0; x2=20000(l/h); y1=0; y2=1024 (10bit=0-10V)

ok we change parameters in AR blocks
at first:I take L/h for an exactly result, because easy800 can`t calculate comma.
Note: If number of pulses low, take a higher gate time for better resolution, but now is refresh time longer.
AR1
Input must be counted pulses, read from DB *36000 {3600s(1hour) *10l (1puls=10l!)}  ->
AR2
result AR1 / xx sec gate time = Liter/hour
check: 3pulses per 5s gate time = 21600l/h -> take min 15s gate time!

I think, you need for your 5cube pump another flowmeter.

bye  Thomas