Flow rate

Hello,
Does NI have any flow rate sensors to measure blood flow rate? If not, does any one know which company has these sensors?
Moreover, to receive the data from any sensor and process with LAbView what do i need? Do i need DAQ?
Thnaks

Hello utd,
NI doesn't provide blood flow rate sensors and I wouldn't know what sensor to recommend. You don't necessarily need a DAQ card, but in order to know if you'll need one, I would need more information regarding your sensor. Therefore, the first step would be to find an appropriate sensor. Some sensors may even be able to connect directly to your computer if they provide the proper cable, but many times the sensor outputs currents or voltages that DAQ cards read. Once the DAQ card reads this sensor output, you can process it and scale it accordingly. Here is a document that could be a good starting point:
http://www.ni.com/white-paper/3536/en
Other people also use discrete amplifiers, filters, and ADC's and then send the information to a computer port, but this can be much more complicated than using DAQ. Good luck on your sensor search!
Andres G
Applications Engineer
National Instruments

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"Once you eliminate all other possibilities, what's left, however improbable, must be the solution"

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Problems Reading gas meter flow rate ni 9402 counter

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Can any one help with this?
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Some ideas:
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What is the max/min range of pulse speeds you are working with and are the default clocks used in the counters and the update rate for your flow / energy calculations are all approrpiate - if you do the calcs faster the "delay" should be smaller ?
Are you using DAQmx channels or DAQassistant to do programming - using DAQmx will give you much more flexibility on how the measurements are processed, and may be better
I presume you are using a counter to produce a frequency output - if you switch to outputing the counter value itself, this will be the cumulative flow over time and that might be useable directly in your energy calculation without having to do an integration (assuming you are using the frequency to give flow rate (e.g. litres per second) which is being integrated). This might eliminate both any delay in seeing the measurement change and the effect of a delay on the integration.
Hope this helps (and is understandable!)

Totalizing a flow rate but not calculating if a negative number

I know how to take a flow rate and produce a totalizer using an integration. What I would like to do is not calculate the integration if the incoming rate should be a negative value. Thanks in advance for your help.

hound,
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How to determine percentage variation in flow rate during various time periods

Hi,
Am in medical electronics division.
I want to simulate infusion pump.
How to do it.

You are confusing me.
In the title you are trying to determine the variations in flow rate, but in the message body you want to simulate an infusion pump.
Can you add a few more sentences to explain what you are trying to do.
Controlling a pump is very different to measuring exact flow rates.
LabVIEW Champion . Do more with less code and in less time .

Control the flow rate of a Merck-Hitachi L-6200A HPLC pump

Hello,
I am trying to control the flow rate of a Merck-Hitachi L-6200A HPLC pump. I already found a VI in this forum in the post listed below:
http://forums.ni.com/t5/LabVIEW/HPLC-pump-feedback-control/td-p/1612428
I set the pump switches according to the manual as well as I have switched the pump to remote mode. Also I adjusted the settings of my COM port in the windows system manager according to pump and LabView settings. The problem is, that the pump won't react do any signal sent from the computer. I used "free serial port monitor" to ensure that a string is sent througt the COM port. Does anyone have any idea what might be the problem here? I'd really appreciate some help. Thank you all in advance,
Greetings,
Hendrik
Solved!
Go to Solution.
Attachments:
pump protocol (SubVI).vi ‏16 KB

dubbehendrik wrote:The problem was apparently the type of string I sent to the pump. In the abovementioned discussion the space string was sent as "\s" but apparently it can directly be sent as " ".
Hi,
It is not the type of string, but how the string is displayed. \s and the space character " " are the same thing. It is mentioned in the response by johnsold in the link you had in your first post. http://forums.ni.com/t5/LabVIEW/HPLC-pump-feedback-control/td-p/1612428

Brush dynamics: flow rate

I am trying to draw with a "stars swoosh" and can vary the size, roundness, jitter etc...
But... How do I reduce the flow rate? I am getting Way too many stars painted onto the canvas.
I can set Scatter down to 1, but this is still 5x as many painted stars as I'd like. The field won't do lower than 1...
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Hello!
William_Donelson wrote:
How? I see no control to increase spacing.
Look under Brush tip shape:
William_Donelson wrote:
Also, if my brush is grayscale, is there a way to introduce color randomly to the stars as I paint?
Color Dynamics is what you want: http://help.adobe.com/en_US/photoshop/cs/using/WSfd1234e1c4b69f30ea53e41001031ab64-77f5a.h tml

Counting pulses and measuring flow rate per second

Hi everyone
I am using a compactField Point (cFP-2220) controller to measure the flow rate. The flow sensor that i have, gives the output in terms of the pulses. I need to count the number of pulses for a particular interval and divide it by a K-factor( constant value) to get the flow rate. If i select the interval to be of a second, i would want to count number of pulses per second and divide it by K-factor to get flow rate ( per second).
How do i count pulses per second and consequently measure flow rate using this count and K-factor.
Any kind of help would be highly appreciated.
Thanks in advance.

You may be able to use the Edit Tempo function to work this out. With you waveform in Edit view Right Click on the time scale at bottom of waveform and select Bars and Beats display. Select a number of beats by highlighting with the cursor. Then again on the Time bar select Edit Tempo. In that dialogue you can try clicking on Extract to find the Tempo ie. beats per minute. Also you can try adjusting the tempo by entering avalue manually to see how close that gets to your waveform.
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Hello All,
What I am trying to do is produce a sinusoidal volume flow rate using two syringe pumps simultaneously; one for the steady-state level (DC) and the other for the time-varying component (AC). I plan to produce the sinusoidal volume flow rate by iniating the steady-state flow rate from the direct controls on one syringe pump and using Labview to produce the AC component on a second syringe pump. One of the pumps that I have available to me is a Harvard Apparatus PHD 2000 syringe pump which does have unsupported labview drivers. Examining the Vi's for the PHD 2000, it looks like I can only set a continuous volume flow rate.
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Hi mpjoseph,
Regarding a specific example, it might be a bit difficult to find a lot of people who have been through that exact application. However, ni.com discussion forum search gave me the following results: http://search.ni.com/nisearch/main/p/sn/catnav:df/pg/2/q/syringe%20pump%20/sb/navsRel
Also, I've found this example program written for LabVIEW 8.0 online: http://astro.temple.edu/~shackman/downloads/HarvardPump.zip The main page is: http://astro.temple.edu/~shackman/downloads.html
You may have already seen these yourself, but I just wanted to show you what I have found so far. Perhaps if you had not seen them, it may at least start you off in the right direction.

Flow rate sensor?

Hello,
Does NI have any flow rate sensor to measure blood flow rate? Also, Do I need NI DAQ to receive data from sensor to display on Labview?
Thanks,
Vahid

Vahid,
Exactly what are you trying to measure? In your original post you mention blood flow rate and in a later post your refer to clip on sensors. The only clip on sensors I have heard of related to blood are for pulse oximetry. That does not actually measure blood flow rate. It gives an indication that blood is flowing and the pulse or heart rate can be derived from it. It is also possible to get a reasonably good approximation to oxygen or coabon dioxide saturation in the capillary blood from the optical spectral content.
I suppose it is possible to get an estimate of blood flow by ultrasound measurements where both the cross-sectional area of an artery could be measured and doppler flow measurements could get velocity. I am not sure a single transducer is capble of both types of measurements and I suspect that the calculations involved to get good estimates of blood flow are quite complicated.
A true flow measurement by turbine flowmeter or positive displacement type sensors requires invasive procedures to install the sensor and special materials engineering to avoid clots.
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Constant flow rate pt 2

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Attachments:
Test_Mix.vi ‏120 KB

You'll have to figure out what flow rates correspond to what voltages. Then create a subVI that will map the desired flowrate to a voltage. It may be a simple scaling function, it may be a lookup table.
One thing I like to use is a combination of threshold array and Interpolate 1-D array. I'll have a couple of arrays with mulitple points where the element in one array that relates to voltage would correlate to the flow rate in the other array. This would give a piecewise mapping of one to the other. The functions will do a linear interpolation between points. The more points you have in the array that correspond to the real profile of the pumps, the closer the actual flow rate will be to the desired flow rate.
One question though, does the behavior change over time? Does changing viscosity or temperature cause different voltage to flow rate behaviors? If so, your problem will get more complicated.

A flow rate by lose of mass (flow: g/min. or g/hours) with the balance reading?

I am using a Mettler Toledo balances to feed a reactor. Balance vi gives me actual (current) weight. How do I get a flow rate by lose of mass (flow: g/min. or g/hours) with this balance reading?
Attachments:
Balances Weight.vi ‏26 KB

Put the current reading in a shift register. Subtract it from the previous reading. Divide by the time between the readings.
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ICloud data flow rates?

I got no response to a similar question I raised a couple of weeks ago from New Zealand; I wonder if anyone can say how much data should be expected to flow to/from the Web while connected to the Internet? I kept running into data limits, like 200MB or 300MB. It seemed plenty for my blogging needs, but in use, I'd get a notice in 20-30 minutes that I'd exceeded my data limit. At first I couldn't believe it, but one hotel techie said that the updating done by iCloud tended to be an issue. So, I turned off iCloud access to my laptop for the remainder of the trip, and the problem disappeared. What is the root cause of this high data usage, and how can it best be controlled while still using the Cloud?

This error is most likely down to the config on HFM. Either the profile you are loading the data with doesn't have permission to write to the intersection or the intersection you are targeting is a no input cell. If you have process management enabled in your HFM app then it could be that the Process unit still has a status of 'Not Started'

DAQ for rotational speed and flow rate measurements

Hello Everyone,
I'm in a new project and want measure the rotational speed of a diesel engine and the diesel flowrate . I want use NI products, but couldn't decide which DAQ card is the most suitable for me.
I want measure the instantaneous speed from a speed sensor which sends a pulses for each revolution. The speed I want measure is less than 3000rpm. The flowrate sensor will give me pulses as well. Also, I need it to have some AIO channels to measure the voltage and current signals. I would be very apprciative if you can provide me with some suggestions about the most suitable DAQ for me.
Thanks
Mike

Hi Mike,
This is pretty easily done in LabVIEW with a
buffered period measurement. My recommendation would be to start with
one of our example programs. A good example to use is called Meas Dig
Periods-Buffered-Continuous-High Freq 2 Ctr.vi. This example can be
found by going to Help » Find Examples in LabVIEW and navigating to
Hardware Input and Output » DAQmx » Counter Measurements » Period or
Pulse Width. There are a few changes that need to be made to change
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1. Adjust the blue enum going into the DAQmx Create Channel.vi to "Low Frequency with 1 Counter".
2. Delete the "Measurement Time" control on the front panel and delete the broken wire on the block diagram after doing so.
3.
Adjust the Samples to Read control to something like 10-100. You can
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It
is important to note that these samples will just be the period of the
gate signal and won't contain timestamp information about when they
were taken. However, you can use the order at which you receive the
data to tell you information about when measurements were taken.
Another thing you can do is take a software timestamp prior to starting
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I hope this helps,
Paul C.

Transmit rate vs. Download speed: should I switch everything to 5GHZ or does it matter?

Thanks in advance for any help that you can give me. I am not well-schooled in networking so, after doing a lot of research and not being able to get clarity, I figured I would write what I understand and hope that somebody here could point me in the right direction. I have 3 airport stations (a time capsule dual band is the primary and 2 airport expresses) and they are all ethernet wired. All my devices are 802.11n capable and all the base stations are n capable. I have no strictly b/g devices, only n devices. No matter what base station a device is connected to, the speedtest.net rate is about 17mbps (I pay for 18mbps) so that is good. However, the "transmit rate" (and I don't really understand what this does) varies depending on what base station my device hooks into. Whenever I am near the time capsule (primary station), my devices hook in at 5Ghz and I get a transmit rate of about 240 to 300 and a 17mbps download speed. But when I hook into either of the other 2 aiport expresses, it shows that I am hooked into 2.4Ghz and the transmit rate is about 50 to 130, but I still get the 17mbps download speed. I know I can change both expresses to only do 5Ghz. Keep in mind, the speedtest.net test always shows about 17mbps download speed no matter what base station my device connects to. I am not sure I understand what the transmit rate indicates. I want to make my network the fastest it can be no matter what base station I use.
So, my question is should I change the other 2 airport extreme base stations to operate as 5Ghz n network only so that I have 5Ghz operating throughout my whole house which will give a higher "transmit rate" and will that make my experience faster even though I already get maximum 17mbps download speed? Also, if you could, please explain to me the difference between ISP download speed and "transmit rate" because I don't really understand the difference...I mean how does download speed affect my experience vs. how does transmit rate affect my experience? Do I really need to have a higher "transmit rate" to increase my speed or is just having 17mbps download speed necessary and the transmit rate doesn't matter?
One other thing you might need to know: I don't have any 2.4 ghz devices that might interfere with my network (my cordless phones are 1.9Ghz)
Thanks again for the help.

Think of it like this.. Change moving data in air to water in pipes.
You have a 1/2" pipe coming from the ISP into your house..
Inside your house you have 5" and 2" pipes.. (this represents the speeds or flow rate if you like, 1/2" is all the ISP gives you.. but your ethernet is a huge pipe.. think of it as infinite for this situation,, and 5" pipe that is 5ghz and 2" pipe is 2.4ghz.. this is just illustration remember it is area not diameter that matters).
If you transfer files between the computer on the TC to the TC hard disk.. you get all the 5" pipe.. very fast.
If you copy a file between computer on the TC and device on the express.. you are limited by the 2" pipe.. everything goes at the speed the 2" pipe can manage.
Now you do something with internet.. 5" pipe can get the same throughput as the 2" pipe because it is only 1/2"
Pipes btw are still in imperial even if you are in a metric country pretty often.
But I hope that illustrates the situation..
If a computer on 5" pipe and computer on 2" pipe are both trying to access internet .. they both still have to share the 1/2" pipe. In a perfect world they both get half your 18mbps if they are accessing it at the same time.. (QoS represent a flow valve that says this pipe should get more flow even if it is smaller so I shut the valve down on 5" to make sure it only gets what the 2" can get.. no more.. to be fair.).
Same as water in pipes.. the 1/2" pipe can never fill the 5" or even the 2" pipe.. the 2" cannot fill the 5" so the fastest would be everything on 5" pipes.. since you are unlikely to be able to afford a 5" pipe from the ISP then you accept everything is going to go slower when internet is involved.
Jumping out of my illustration..
Apple made 2.4ghz max out at 150mbps..
Although some of the later stuff can get better than that,, 217mbps.
The 5ghz is faster because it is has more bandwidth.. up to 1200mbps in the newest AC .. 450 on Gen3,4 TC and 300 on the older gen1,2
BUT the range is poor.. so generally better sticking with 2.4ghz for express.. they are not high power devices at all.
2.4ghz has better range and penetration.. you are going to be just fine with internet access.. and your setup is actually working really well.. There are some overheads on wireless so you do not quite hit wired speeds.

Flow rate

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