Pulse input from flow meter?

I have a basic multifunction PCI 6013 card. I would like to read in the pulse input from a flow meter (around 20 pulses/sec) and convert it to volumetric flow rate. I've scoured the example vi's and forums to no avail. There are counters on the board so I believe this is possible. I'd only need to read data for a short duration because only average flow rate is needed. Thanks for any help.

You were close.
Look for the examples on gated pulse counting.
Try "count time easy.VI" (check your board spec's to amke sure your example fits your hardware).
Ben
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

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Changing flow meter's mode during the measurement

Hi,
I have the CMOSens EM1 gas flow meter which can be setted to either temperature mode or flow rate mode. However, I will need both temperature data and flow rate (in ml/min) data in order to calculate the mass flow rate in kg/min. I am very new to LabVIEW so I have no idea what I can do. What I have in mind is ... doing the measurement with the sensor in temperature mode for ~ 1 second, then change to flow mode for ~ 1 second and change back to temperature mode and so on, until we stop the measurement. So output in data file might be something like this ...
Time   Data
0       temp
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2       temp
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where temperature and flow data can be in different column. Note that the fastest sensor response time is 5 ms.
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Bew

Hi SnowMule
Thank you for your suggestion. The data from flow meter is already in volume per minute so I only need to know density of gas at temperature T to find mass flow rate (...do I miss anything?). It's nitrogen gas and there's some online database availble to get the gas density from known temperature. That's why I want to read the temperature from the flow meter as well.
Additional thermocouple would be a solution if I cannot have LabVIEW to do the job for me.
Thanks again!

How to measure pulses from 24v flow meter sensor with NI 9411

Hi,
I have a 24v pulses flow meter sensor, how is it possible to connect it to My NI 9411 ?
Regards

duplicate
Steve M.
National Instruments France
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Flow Meter VI - Pulse Count - Help Needed

Hi,
I am working on developing a Flow Meter VI, I am using a flow meter with a pelton wheen that outputs a stream of pulses in proportion to flow.
The flow meter output is attached to the counter line of my 6501, and the pulse count is multiplied by 1.41 (per datasheet) to give ml.
I have the attached VI but not sure exactly what it is doing, would someone mind explaining how it works and how it could be optimised, thanks.
Regards,
Ger
Attachments:
Flow Meter.vi ‏52 KB

Hi Ger,
Looking at the VI it seems to be just acquiring some data off of your 6501 card, and just edge counting the number of pulses received and then processing the data to give the result of flow. It seems fairly simple in terms of what it is doing, but there are a few optimisations I can reccomend to you. In your VI there is an unused shift register in the first for loop which I would reccomend removing as it doesn't seem to be strictly necessary. In the second for loop, there is an uninitialised shift register, and I would reccomend that you initialise that with a suitable value unless you specifically need it, as otherwise it will just use the default value of the data type, which in this case is 0.
Another optimisation you could use is replacing the DAQ assistant with DAQmx functionality however considering how simple this code is currently, the DAQ Assistant should not cause a problem, however if you wish to expand it in the future I would reccomend looking into using the lower level DAQmx VI's.
Best Regards,
James Kent
James Kent | Applications Engineer | National Instruments UK & Ireland
w: uk.ni.com | ireland.ni.com

NI 9422 - Flow Meter - Reed Switch

Hi all,
I am curious if the NI 9422 can accept signals from a flow meter operating on a reed switch. I understand that when operating on this type of sensor (as opposed to a hall effect), no power supply is required. So does the circuit simply send the sensed pulses back to the card for a counter reading (I have the card configured in counter mode).
The spec on the device is that it is a reed switch two wire SPST N/O contact.
I am asking this because our other flow meters are operating on the hall effect sensor which use a single circuit to both power the flow meter as well as take in the sensed pulses.
I want to know if the card can handle either of these switches.
Thank you.

Hi Cuearospace,
I just wanted to clarify that you want to read from the flow meter and not the switch. If you are trying to read from the switch, here is another discussion on the same topic but with a different card:
http://forums.ni.com/t5/Digital-I-O/USB-6501-magnetic-reed-switch-input/td-p/414543
But if you are reading from the flowmeter, this should be fine as you just read in the signal when it is generated.
Paolo F.
National Instruments
Applications Engineer

Labview flow meter display

Hi all,
I have an aquamaster S flow meter with its programming cable, meaning I could change the max. frequency, number of pulses/unit, FSD % etc. I tried writing a program where the labview would take the voltage and convert it to a flow rate. I'm not sure what I'm doing wrong but I could never get the flow rates to match. I tried playing around with the pulses/unit and max frequencies and somehow manage to get a fairly close number but the minute I change the flow rate through the system the flow rate in labview goes all over the place. The range of voltages I get from the meter are 1.5V to 5V. The maximum flow rate I'm expecting in my system is 2.6lpm.
Please help !
Here is the link to the flow meters program menu in case anyone wants to check it out:
http://www05.abb.com/global/scot/scot203.nsf/veritydisplay/70da9c6555f9305580256f020025d79d/$File/IM_AMS_QRG_5.pdf

Aquaman89 wrote:
Hi all,
I have an aquamaster S flow meter with its programming cable, meaning I could change the max. frequency, number of pulses/unit, FSD % etc. I tried writing a program where the labview would take the voltage and convert it to a flow rate. I'm not sure what I'm doing wrong but I could never get the flow rates to match. I tried playing around with the pulses/unit and max frequencies and somehow manage to get a fairly close number but the minute I change the flow rate through the system the flow rate in labview goes all over the place. The range of voltages I get from the meter are 1.5V to 5V. The maximum flow rate I'm expecting in my system is 2.6lpm.
Please help !
Here is the link to the flow meters program menu in case anyone wants to check it out:
http://www05.abb.com/global/scot/scot203.nsf/veritydisplay/70da9c6555f9305580256f020025d79d/$File/IM_AMS_QRG_5.pdf
Are you sure you widget is giving you an analog signal?
Many of the flow meters I have worked with gave me pulses* that I counted to track the flow rate.
Ben
* the interanal cap at the input of a instrumentation amp could be filtering the pulses but because the cap discahrges non-linearly, when you change freq the scaling will be off.
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

Turbine flow meter conversion

Hi,
Apologies for the query but this software is all new to me . I have a 9188 cDaq 8 way chassis containing several modules including 2 off 9401 counter modules, I am running signal express version 6.0.0.
My issue is I have 3 miniature turbine flow meters (Gems units FT-110 series) which are giving out 5V square waves at varying pulse widths dependant upon what the flow is. I've scoped the input to my 9401 and the signals look good so am assuming it's my signal express configuring that is causing the problem,
I've wired the +ve and gnd outputs of the flowmeters to DIO0 +Com, DIO1 + Com and DIO3 + Com on one of my 9401 cards.
I can see the pulse count increment on measurement & automation explorer when I run the test panel for that module and look at the edge counts so my system can see the pulse trains coming in.
When configuring signal express I need this to read in l/min, 58-575Hz should equate to 0.5-5 l/min, however I cannot seem to convert the pulses to l/min.
If I select DAQmx acquire>counter input>frequency it gives me the option of custom scaling but every time I run it I get the DAQ assistant error flagging up. I tried numerous timing settings with no luck. The only time I've got this to count succesfully is using counter input>edge count but I'm stuck on how to convert this into l/min as there is no scaling function (that I'm aware of!)
Any help appreciated.
Solved!
Go to Solution.

I think he's referring to l/min as Liters per minute, and i'm assuming the Freq to Flow are the values that corrolate to the scaling.
If that's the case; Carl, it sounds to me you need to setup a custom scale. You can do this in the Channel Settings tab in the DAQmxAcquire step. Under custom scaling select Create New and select Map Range Scale. You min/max Freq should equal your min/max flow rate.
I've attached some screenshots for reference.
Let us know if we're on the right track, otherwise we may need more info; I.E. .seproj file and a bit more info on the flow meter (connection type, output signal, etc).
Also, a brief glance at the documentation on that flow meter recommends the use of a pull-up resistor. May want to look at that as well.
SCXI- 1000 Chassis w/ 1346 adapter
PCI 6281 DAQ card
SCXI- 1520 Bridge Board w/ 1314 Terminal Block (x2)
SCXI- 1180 Feedthrough Panel w/ 1302 Block
Signal Express 2014.
Win7 Enterprise
Attachments:
freq_lpm.JPG ‏82 KB
dmxA.JPG ‏100 KB

Help Explaining Flow Meter VI

After much tinkering I appear to have worked out an effective VI for use with a pelton/turbine type flow meter. The flow meter outputs a stream of pulses that
are being counted on the counter line of my 6501. Unfortunately this eureka moment has happened somewhat by chance and I am hoping someone
would be kind enough to explain step-by-step or in very basic terms for the beginner (me) how the VI is operating, thank you.
Regards,
Ger
Solved!
Go to Solution.
Attachments:
Flow Meter VI.vi ‏53 KB

Ger,
Welcome to the Forums and to LabVIEW.
If you have not already done so, please work through the online tutorials for Getting Started With LabVIEW. The answers to some of the questions you may have are probably in there.
A brief description of your VI:
1. The overall structure is a For loop. This runs for the number of iterations wired to the N terminal, in your case 5.
2. The loop timing is determined by the longest time required for any part of the code inside the loop to execute. On the first iteration the DAQ Assistant configures the counter and starts the measurement. On all subsequent iterations it simply reads one count. On those iterations the 25 ms Wait will dominate.This VI runs about 40 iterations per second (for 5 iterations).
This means that the program will run about 5*25 ms = 0.125 s and then stop. If you are running it for more than 1/8 second by using the Run Continuously button, STOP. That is intended for certain kinds of troubleshooting only.
3. The waveform chart and the Flow rate meter will only display the last value from the five iterations. (This also suggests that you are using Run Continuously)
4. The shift registers in this VI do nothing. The upper shift register calculates the cumulative count from the flow meter, but the result is never used. The lower shift register has nothing wired to the left terminal inside the loop. It could be replaced by a terminal.
Suggestions:
1. To avoid the use of Run Continuously replace the for loop with a while loop. Add a Stop button on the front panel and wire it to the Stop it True terminal in the loop. Move the Waveform Chart and Flow Rate terminals inside the loop.
2. Check your pulse to flow rate algorithm. The time interval for the count must be considered. For example if the counter records 25 pulses in 25 ms, that represents 1000 pulses per second. This is not what your VI will show.
3. Look at the Examples for code which uses counters.
Lynn

Totalizing brook flow meter

hello, I am using fieldpoint AI 110 in labview 7.1 to read my brooks flow meter input. I have a vi which reads the flow in grams per minute. I want to totalize the flow to reach a certain stopping or set point. Is there a VI available?

Hi Stan,
This can be done by basically keeping track of the time your read-loop takes (using tickcounts and shift-registers). Make sure you convert this time to minutes, and then multiply by the value read from the AI point. You now have the grams collected in one loop. Then, use a shift register to keep adding these grams from each loop to get the total so far.
Hope this gives you some ideas.
-Khalid

How to get pulse readout from BPM analysis in biomed startup kit

Hello,
We are trying to obtain an instantaneous pulse reading from a Vernier Go EKG sensor. We tried writing our data to an array in a for loop, then exporting the array to the "array in" node on the BPM analysis tool. We would like a chart displaying the EKG (which we have) and the instantaneous pulse readout (which we get a readout that says not a number). HELP!
Attachments:
EKG.vi ‏18 KB

Hi TFleck!
I want to premise my response by saying Steve.J had a great suggestion, there might be users in the Biomedical User Group who can help you with this hardware or maybe you could contact Vernier as the Vernier Go EKG sensor and the VI in your attached file uses SubVIs supported by Vernier. In addition, it looks like Vernier provides some tutorials.
Given that suggestion and that I do not have this hardware to test with, there are a couple of things in the VI that look like they could be related to your issue. First, the parameters cluster line from the Read VI output is not connected through to the BPM VI. You might have to wire the parameters so the BPM VI gets the correct configuration data. Second, the BPM VI has an input called Analysis method and the default for that terminal is point-by-point analysis. It looks like the VI you wrote is using data array analysis, so I would recommend creating a constant on that terminal and trying Analyze Data Array.
Hopefully that helps, but if not, maybe someone in the Biomedical User Group knows more about the device or you can contact Vernier and they can support you with some examples.
Milan

Processing cyrilic input from HTML FORM

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I have faced the problem with processing the cyrilic input from the HTML form, The JSP code to receive it and store it can`t do it properly. The <page> directive has ContentType='text/html; charset=UTF-8' and the HTML itself has <meta> tag for the same charset; Only problem is that cyrilic symbols are coming from
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Have a look at
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Jacek

Cole-Parmer DAQ with ABB Aquamaster-S Flow Meter

I have a Cole-Parmer 18200-00 DAQ that I'm using to measure the flow rate using an ABB Aquamaster S. The flow meter sends out a pulse that is equivalent to the flow rate in the system. I'm having some trouble writing a program that would give me an accurate flow measurement. I tried converting the pulse into a voltage by using a resistor connected into the analog port but instead of getting a fixed or approximate number for the flow rate I get a range of flows. I'm guessing I should connect the flow meter to a counter port but I don't know how ?
I might even be on the wrong track to beging with. Please Help ??
I'm attaching the current program I have writtent and the flow settings on the flow meter.
Attachments:
Flow Meter.vi ‏86 KB
Flow Program.docx ‏14 KB

Unless I am confused by your text document, you can simply count pulses.
One pulse means that the pinwheel rotated one time.
They have calibrated one revolution to mean that 1/20th of a Liter has passed.
Therefore, your volume will be:
V = (# pulses) * 1/20
And your flow rate would be:
Q = V / (t2 - t1)
where t is time in whatever units you want.
Cory K

I want to kill a particular process chain from a meta chain..

Hi All,
I want to kill a particular process chain from a meta chain as, its having some technical issues.So what is the procedure.to handle this process..
Thanks..

follow these steps
1.Go to the chain which you want to kill .
2.Go in the log view->top menu bar execution tab.>Remove from schedule.
you are done
Another way (bit complex but will work )
1.Go to the process chain running (which you want to kill) in the log view copy the logid (lef hand side of screen you can get that)
2.Open a new session ,Go to se37 enter function module RSPC_PROCESS_FINISH -->execute it
3.Now again go Log view of the process chain right click on the start variant>display messages>Chain tab
copy the variant ,instance ,date time etc
4.IN execution screen of RSPC_PROCESS_FINISH enter the variant,instance,data time,logid and Type=TRIGGER
status = R.
Actually you will see something like this in input screen
I_LOGID -
>from log view in RSPC
I_CHAIN
I_TYPE   -
>TRIGGER for start variant
I_VARIANT----
>from log view in RSPC
I_INSTANCE------>from log view in RSPC
I_STATE     -
>R
I_EVENTNO                       00
I_HOLD
I_JOB_COUNT
I_BATCHDATE   -
>from log view in RSPC
I_BATCHTIME                     00:00:00
I_DUMP_AT_ERROR
Thats all and your are done.
But I would suggest Remove from Schedule will surely work....If you have any doubts let me know.
Regards,
Rocks

Positive displacement flow meter

I have a spur gear positive displacement flow meter and a sensor which counts the number of impulses (square-waves). 1800 impulses indicate 1 gallon. How can I measure the volumetric flow rate in Gallon per second? What I plan to do is to count the number of impulses in 0.01s and times as N, and then times 1 gallon/1800 to get the volume, and then divide the product by 0.01. What if the square wave is not complete when the 0.01s period is not complete.

Ravens Fan wrote:
Look for Basic Level Trigger Detection.vi down kind of deep in the waveform, analog waveform palette. It will allow you to search for a rising edge or falling edge in the waveform. Repeatedly do that find all the rising edges in a given sample of the waveform.
Also, look in the example finder. Something like the Trigger Counter example might give you some ideas.
I know how to use the Basic level Trigger detection now, and I am trying to counter the number of rising edges. I am intend to use a cases struture to do it. When the trigger detection is true, then do the loop. The problem is how to memorize the value of last time. I also looked at an example file from the forum. But that one makes me confused.
Attachments:
basic trigger detection.vi ‏52 KB
Detect All Triggers.vi ‏25 KB

Looking for sensiron liquid flow meter VI

Can anyone steer me to a VI for a Sensiron liquid flow meter? I am using a ASL 1600-20
Thanks
Solved!
Go to Solution.

Hello,
I could not find any code on either NI's Development Zone or on www.ni.com/idnet (where we store drivers for 3rd party hardware). I did find two drivers for humidity sensors from Sensirion. I've attached the link below. While we do not currently have any code written, there are resources available to help you create your own driver. First you will need the manual on the ASL 1600-20. I searched Sensirion's site, but only found the second link below. You may want to contact Sensirion and see if they have any documentation on how to communicate with their flow meter using the serial protocol. We also have some tools available for you at the last link. At the bottom of the page of the third document below, there is a tab for "Learn to Build Instrument Drivers". Here we have many links to videos and article to assist you. Good luck!
Sensirion Drivers on IDNet
http://search.ni.com/nisearch/app/main/p/bot/no/ap/tech/lang/en/pg/1/sn/catnav:id,n2:RS.sensirion,ss...
Micro Flow Meter Series ASL1600 for Liquids
http://www.sensirion.com/en/02_liquid_flow_sensors/03_liquid_flow_meter/03_asl-1600.htm
IDNet (Learn to build drivers)
http://www.ni.com/devzone/idnet/
Regards,
Shawn S. | NIC
Instrument Driver/IVI PSE
National Instruments

Pulse input from flow meter?

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