Flow meter M3 pulse to liters/second... Advice

[Guest gsxr1000au]

I have a magflow meter which is programmed to pulse every m3. The system may run from 30m3/H to 720m3/H. Any suggestions on how i can convert the pulse signal to liters/second and be fairly accurate?

 

Using Unilogic (latest version) and standard input card. 

 

 

[Alexander]

The accuracy is dependent upon the flow meter's pulses. Since it only has an output pulse every cubic meter, or 1000 liters, than it will have an accuracy based upon the pulses received in a given hour. It depends on if you calculate it based on the cumulative total per hour or if you attempt to calculate each second.

 

For example up until you receive your first reading it will have an average of 0 liters per second, even though this is not true. Once you receive the first pulse it will only be able to calculate the average of 1000 liters over how ever long it took to generate the first pulse. Since the range is 30-70 pulses per hour than that is only a pulse every 2 min or at best every 50 seconds.

 

One possible solution is to log the time between pulses and take an average of a certain amount. This will not be entirely accurate if the system is changing but is the best way to accomplish this using only a flow meter based upon volume, and not time.

[bobnorway]

reprogram the magflow for 1000 pulses per m3.

if necassary use the high speed counter input.

save a copy of counter value every second

 subtract from previous value copy.   

[tadesss]

Someone can send sample program

[HigHTech]

The only way is increasing the number of pulses/m3. If I need to measure flow then I try to use a flowmeter with 4...20 mA, or use the pulse output but using a HSC (with enough pulses/u time), then you can calculate the frequency and get the m3/s.