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.
This type differentiation tends to be noisy so you may need to do some smooothing of the data.
Lynn

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I need to update my iTunes and iPod touch,iPad and iPhone but they were set up with a hp laptop that i sold i tried to update my iTunes and apple devices but it tell's me if i update i will lose all media on my devices and to update with the original com

I need to update my iTunes and iPod touch,iPad and iPhone but they were set up with a hp laptop that i sold i tried to update my iTunes and apple devices but it tell's me if i update i will lose all media on my devices and to update with the original computr

Go to www.ecamm.com and d/l PhoneView.
To prevent a sync when plugging in the iPod/iPhone - hold down the 'option' and the 'command' keys when plugging in the iPod/iPhone - key the keys down until the iPod/iPhone is listed under the Devices list in iTunes - this will prevent a sync from taking place.
With PhoneView you can take the content from the device to the iTunes library.
MJ

Is the sample rate half with the snd read waveform.vi?

Hi Guys,
I plan to use the PC soundcard for data acquiring with the standard LV "snd read waveform" vi. During programming I found that the sample rate is the half of the adjusted value. For example when I set
- the format to 8bit mono
- the buffer size to 11025 byte
- and the sample rate to 11025
then the operation takes 2000ms. I would expect 1sec.
Used system: LV7.0, WinXP SP2.
Does anybody know the reason? I have to use 44100Hz sample rate (44100 "individual" sample per secundum) in my application.
Thanks,
Tomi
Attachments:
Panel.jpg ‏18 KB
Block.jpg ‏15 KB

To be more precise, that's the time take for the below mentioned finite cycle
SI config>> SI start>> SI read >> SI clear.
Its this 'entire' process which takes 1997 milli Sec
Now, what you really have to check is wheather your 'SI read' function is living up to the sampling rate you have set!
Check that by putting your 'time elapsed' check for SI Read function alone!
Hope this helps
Regards
Dev

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.
Lynn

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

I have a year old iMac and Macbook, both on 10.7.3. Every time the iMac goes to sleep I lose wi-fi. No problem with the Macbook and iPad. A lot of people seem to have the same problem. What's the solution?

I have a year-old iMac and Macbook, both on 10.7.3. Every time the iMac goes to sleep I lose wi-fi from Airport Express. No problem with the Macbook or my iPad. It seems a lot Mac users are having the same problem. Is there a solution? Does Apple have a solution?

Sometimes there are problems.
Somethings to try but probably won't help....
1. Repair Disk Permissions
2. Startup in Safe mode by holding down the "Shift" key....
3. Reset the P Ram by holding down the "Command/Option/P/R" keys at the same time...
The above are standard items to do on any Mac from time to time.
I repair permissions at least once a month....
The other 2 periodically as they do straighten things out when they get out of whack....
Thanks for the feedback.

Producing a voltage that coresponds to a setpoint for a mass flow controller.

Hello,
I have a mass flow controller that requires a voltage output signal from my DAQmx board (SCB-68) to maintain a setpoint. This set point is a voltage that corresponds to the desired flow rate. I have produced a scale for this linear controller but I do not know how to use it.
I know how to create a vi that reads a voltage input, I can also write one that sends the same voltage input back throught the output. I can not write one that sends a constant voltage output corresponding to a flow rate.
Could somebody help me out with this?
Dan

Hello,
First, tp upload code (or any document) it is quite easy, just select the file, by clicking the "browse" button... see image below (I'm sorry it's all in french... 'cause I am french ! "Parcourir" means more or less "Browse" ) :
About your app, well adding a channel doesn't require to duplicate the whole code... Developper are always trying to do things with the less code possible . Check VI attached and tell me if it matches your needs.
Message Edité par TiTou le 03-23-200601:26 PM
When my feet touch the ground each morning the devil thinks "bloody hell... He's up again!"
Attachments:
Gen 2 Volt.vi ‏98 KB
Clipboard01.png ‏14 KB

Mass Flow Meter

Hi all,
I am using PCI 1710 board to control fuel cells vlaves and Mass Flow Meter.
Could any one help in getting the mass flow meter show me the Flow rate of the Gas.
I am using Burkert 8006 Mass flow meter and I wanna connect the MFM to the PCI 1710 and jus want to show me the flow rate. Could any one tell me, to which pin should i connect the MFM to, it has a 15 Pin Sub HD Socket. (Currently taking output from the Process Value Output and Process value ground and connected to the PCI1710 A11 and A10(Analog)). Thank. Awaiting your response.
Regards,
Vijay

What connections do you have to this device? According to the manual you should have a 9 pin D sub connector for the 8006 model. If you have a 15 pin D sub I will try the 15 Pin D sub connections that are in the book on page 7.
If this does not work I am not sure what to tell you. It should use RS-232 with these connections. Did you get a MFM that has communication protocols?
Tim
Johnson Controls
Holland Michigan

Daily flow rate totals over several days displayed in Lookout 6.1

I need to display running daily flow rate totals in lookout for several days. The expressions would be for "today", "yesterday", "two days prior" and "three days prior". I am using accumulators to do month to date totals and running averages. I am stumped as to how to accomplish the daily totals. This application is using Lookout 6.1.
Thanks,
Brad Adams
Service Manager
CommTech
Email: [email protected]
Phone: 615-889-4756
Cell: 615-477-8975
"Once you eliminate all other possibilities, what's left, however improbable, must be the solution"

Look into the Sample object. You can trigger this object to log the daily value at midnite.
Previous samples are retained as sample.2, sample.3 etc.
Regards,
Bob L

Problems Reading gas meter flow rate ni 9402 counter

2015/07/13
Can any one help with this?
I have been trying to overcome the problem of the delay were a value is retained at the output of the counter for a period after the gas meter has stopped. This is causing me a problem as I am feeding this value into an integrator to get a measurement of energy used.(in the system I have other inputs such as gas pressure, barometric pressure and temperature)
To solve this I decided to use the quadrature encoder input. I have taken the pulses from the gas meter and built a ripple counter from two JK flip flops (with logic to convert output to gray code) I have also added extra gates to counter propagation delay in the circuit. I am using a line driver IC SN75158PE4 at the output of the circuit. Can you see any problem with this method. I only ask because if I use X1 mode I get intermittent reading as in 0, reading, 0 reading etc. If I use X2 mode I get a value that I believe is correct but am still unsure about it. and in X4 mode I get a value that is lower than expected.?

Some ideas:
Monitor the raw DIO data showing the pulses, to make sure there are no spurious pulses after the flow is stopped or if there is any "bouncing" of the signal that might give a false hgh flow as the flow drops to zero - if there are you'll need to find something to deal with that.
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,
you may use an EXPRESSION OBJECT to eliminate negative values, something like:
if(YourSignal.value>0, YourSignal.value, 0)(if the value of your signal is greater than zero, use your signal, else zero)
and connect the output of this object to INTEGRAL.
Hope this help
JPSS

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 .

Connect to MKS Alta 1480 Device Net Mass Flow Controller

I have a MKS Alta 1480 mass flow controller (MFC), MFC Manual, Labview 8.2 and NI PCI-CAN card. I know have the MFC wired correctly because I can operate it using another program on the PC that used the deviceNet interface. I want to talk to it via Labview. Everything looks OK using measurement explorer. I have the NI-DNET pallet. I know the MACID. I have downloaded the EDS from the manufacturer.
Here is what I am lacking: A general clue about the DeviceNet interface. Is there any example code out there that could get me started? Are there any tutorials on how to figure out the Dnet protocol? I am used to serial devices command--> response. I don't know anything about Class, Object, attirbutes.
Thanks,
Joe
Solved!
Go to Solution.

Joe, you can read MFC Flow value from S-Analog Sensor Object.
Class Id 49 (0x31), Instance Id 1 (0x01), Attribute Id 6
(0x06)
The default Data Type is Integer and Data Units is counts
If you want read from assembly object, you will
have establish polled IO connection, then use Read DeviceNet IO.vi to read
flow.
Attachments:
MFC Integer Flow.png ‏4 KB

Mks mass flow controllers only giving 2 sig. figs. over deviceNet and labview

We can only read 2 digits (before the decimal point) on an MKS deviceNet mass flow controller using Labview 2013. Does anyone know a solution to increase the resolution on this device? We should be able to read 3 digits past the decimal point.

Hi David,
Could you also specify the type of mass flow controller device?
According to our engineer, we had the APIs to set the attributes of DeviceNet device, but the specific type of the device is required. Attached is the document of some device type. You could turn to page 75 to see there the S-Analog Sensor Object Attributes::FlowDataType could be Get/Set.
Attachments:
1485A-1480A-185A-180Aman.pdf ‏964 KB

Mass flow controller

hello,
does anyone have or know of a vi that can be used to read and display mass flow of a gas?
i have a mass flow controller(MFC) and it reads the gas flowing thru a pipe (or a tube, forexample). i want to be able to take the readings or signals from the MFC and display it on the front panel.
does anyone have something(VI) of the sought that i can maybe modify to do what i'm trying to do?
thanks
-r

A lot of MFC's have an analog out denoting the "is" value of the mass flow.
Connecting this analog out (from the MFC) to an analog in of a DAQ card will allow you to record the values.
This is an easy thing to do (If your MFC has a simple analog out), so I'm not sure if you'll find ready-made functions for it.
Shane.
Using LV 6.1 and 8.2.1 on W2k (SP4) and WXP (SP2)

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

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