Speed measure with DAQ and torque transducer
Can anyone tell me how to convert the voltage i get from torque transducer, which can measure torque and velocity eather. I made a program with labview, but it gives me some voltage. I'd like program converts me that voltage to a velocity.
Thanks for answers.
First of all, we need to deeply understand the signals we receive from the sensor.In my opinion, the information from the datasheet is not the most comprehensive
Sensor requires 12V DC, 160mA excitation.
Torque: 0V-10V, -10V-0V depending on direction - should be connected to AI
Speed 60 pulses/rev - should be connected to counter 0
Angle 360 pulses/rev (two signals- angular encoder) - should be connected to counter 1
What I would recommend is you started with LV examples for:
Hardware Input and Output -> DAQmx
Torque - Analog measurements and then scale the signal to result in strains
Speed - Counter Measurements -> Digital Frequency
Angle - Counter Measurements -> Position
Please find the proper example, scale them properly, make each work individually and in the end, integrate the three examples into one single application,
Mircea
Similar Messages
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Speed measure with DAQ, how to override the noise
Hello.
I try to measure spped using the counter input. My VI didn't work, so I look at the singnal I get from the encoder and I saw, I get a lot of noise in my signal. That's why program shows wrong values. I connect my signal between PFI8 and DGND on my DAQ 6212. My encoder (torque transducer) gives me 60 pulz/revolution. Is it possible to nullifythe noise with program, or there is a problem with ground. I tried many different ground options, but didn't work
Hope you have any idea.
Thanks a lot.
SimonHello Mateusz. Thank you for responding me.
You can see my signal taken from scope and check my vi file. Noise causes regulator of the motor I drive. If regulator is switched off there is no noise and if I turn my motor by hand, I get correct values of velocity, but when I turn on the controller, I get full of noise in my signal, so DAQ card reads all those noise as many signals, so it displys velocity much greater than it's real. I moved my daq card away from controller as much as possible and used coaxial cable, but noise still appear. I hope you have any idea.
I hope you don't mind, because notes in my vi are written in my language. I just wrote them, that I can see what I was doing.
Regards. Simon
Attachments:
DAQmx velocity.vi 45 KB
scope_0.JPG 118 KB -
Speed measurement with PCI6601
I am building an application for measuring two linear encoders ( micrometers ) and one quadrature encoder for measuring speed of one motor.
At the moment I can read the two linear encoders with the "position measurement" option for the PCI6601.
But I have trouble to calculate in an easy way the speed of the rotating motor in RPM.
Could anyone have any easy solution for doing this?
Thanks
Massimo VisintinMassimo,
A few notes in no particular order:
1. Re: future use of last counter for another speed measurement. With the 6601, you only have 1 DMA channel available for buffered measurements. A second buffered measurement would have to be manually configured to use interrupts.
A buffered measurement will give you much better precision, but you may be better off starting with a simpler unbuffered approach when getting started.
2. How accurately do you need to measure speed? And how often do you need a new measurement? It sounds like you're reasonably happy with a simple speed estimate made about once per second.
3. Have you considered making a separate loop for the speed measurement? You could simply read the count once per second (unbuffered) and put it into a shift register. Then estimate speed as delta counts divided by delta time. A small enhancement would be to also store the time from 'Tick Count (msec)' on each loop, and use a measured delta time rather than an assumed one in the calculation.
Note that with this method, it's best to run unbuffered to avoid the lock-up problem you saw. It'll also be simpler to add your second speed-measurement counter task in the future.
4. Again, there *are* solutions available involving precise buffered measurements. I recently posted a DAQmx-based example that includes an instant-response buffered read (toward the end of this thread.). But I'd recommend first getting a simpler approach to work, then coming back to the buffered measurements later when you're sure you need more precision.
Good luck!
-Kevin P. -
Wireless speed difference with WEP and WPA2?
I am connecting to my FiOS router wirelessly, since I was new on wireless networking, I did lots of reading they all say WEP encryption is flawed, and WPA2 should be used instead. So I changed the router's default WEP to WPA2 the same day I got FiOS installed. When I check about 10 of my neighbor's wireless networks, 8 of them using WEP, 1 has Security Disabled(D'oh), and I am the only one using WPA2-personal. My question is will I see any connection speed difference between using WEP and WPA2?
Solved!
Go to Solution.in every day use, your experience will vary. There is more "going on" with WPA and WPA2 than with WEP, such as message checking and encryption key changes for each data transmission, so these, combined with other possibilities inherent in computer-connected-to-internet use, can slow you down. Another factor: There will be more administrative overhead to use WPA or WPA2. such as if you ever have to reset the router (to default settings), the default is WEP, so you have to go into the router to then chage it (or import a config file you previously saved on your PC). AND If you need to call verizon tier one tech support, they only support default settings. Their premium service is called Expert Care.
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Speed issue with TC and Airport Express 802.11n in WDS mode...
Here is my problem.
I replaced my older base station / Express duo with
a new Time Capsule (1TB) and a new Airport Express (802.11n).
I set up the network with the TC as base station running a WDS network (WDS main) and the Express is the WDS remote.
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So my question is why does the Express not communicate at >54 speed rate with the TC?
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Any thoughts?Instead of using WDS, you should take advantage of the "Allow this network to be extended" option that is available for the 802.11n AirPorts including the TC. WDS only operates in the 802.11g radio mode.
Here's the basic setup:
o If practical, place the base stations in near proximity to each other during the setup phase. Once done, move them to their desired locations.
o Open AirPort Utility and select the base station that will connect to the Internet.
o Choose Manual Setup from the Base Station menu, or double-click the base station to open the configuration in a separate window. Enter the base station password if necessary.
o Click AirPort in the toolbar, and then click Wireless.
o Choose “Create a wireless network” from the Wireless Mode pop-up menu, and then select the “Allow this network to be extended” checkbox.
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o Choose “Extend a wireless network” from the Wireless Mode pop-up menu, and then choose the network you want to extend from the Network Name pop-up menu.
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(ref: Page 46 of "Designing AirPort Networks Using AirPort Utility). -
Position for Programmer experience with DAQ and C++/Labview
We are company located in the Bay Area of California and looking for
a programmer experienced with programming (from scratch) DAQ boards for
signal generation (sine/triangle/sawtooth) waveforms as well as DAQ
digitizers, FFT, and data displaying.
You should be
able to program these cards using C++, but should have strong knowledge
of labview as well. You may be asked to translate and migrate labview
VI's to the C++ enviroment.
Job applicants from
the Bay Area, as well as abroad are welcome to apply.Those outside of
the Bay Area can develop code at your own home office and must have
C++/labview on a suitable computer for programming.
Applicants should apply by sending an email to: jobs at intereasemedical dot com and indicate IE002 as the job position code.
Do not post your resume as a reply to this forum post.
Do include your resume in PDF or DOC format
Do
include your billing rate and if you are authorized to work in the U.S
if located in the Bay Area. We do not provide H1B sponsorship.
Responses without the above information will not be considered.
Thank you!Hello, I have much experience with DAQ, C++ and Labview. How to apply for this position?
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Acquire with DAQ and write DATA on can bus
I acquire data with a 6040E card and I would to send some of these data on CAN bus (card CAN DS) at 100ms but my industrial PC crash (1.2GHz 512Mo win2000 LV6.1).
The frequency of the acquisition is 1KHz and i aquire 4 data, my while loop run at 4ms, all seem to be normal.
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In two differents loops it's the same problem.
When I communicate with RS232 instruments during this acquisition i have no problem.
Can I do it? what is the problem? ...
Thank you for your response.
XAVIERI'm using NI CAN 2.0, NI DAQ 6.9.2, and NI VISA 2.6.1.
In fact I would like to acquire data with a 6040E and 6602 counter at the same frequency (250Hz). I have a continuous acquisition of 16 DAQ channels with a sampling rate of 1KHz. I read 4 data in my buffer (1000) but only the first element of the buffer interresting me. The time of my while loop is 250Hz and all this 250Hz I read the value of my counter (simple read). A buffered read with the counter is not good because of the low frequency of my input signal. That increases the time of my acquisition loop.
I use the RTSI bus to synhronise the starting of the counter with the ai scan start of my DAQ card.
All the 100ms (in the same while loop) I write 1 CAN frame (1 2 3 4 5 6 7 8 at this time) w
ith ncwritenet.vi of the frame API.
But after few second (5 to 60) the image of my computer freezes, my mouse doesn't move, I can only shutdown my computer to restart it.
I have find only this solution to synchronize my DAQ and counter acquisition but it takes many CPU time and it would be the reason of the crash.
Thank you for your futur response.
XAVIER -
Help required with DAQ and waveform generation
Hi,
I'm using DAQ 6024E card for waveform acquisition using LabVIEW 8.2 version. I've also attached my vi for your reference.
My next step is , I want to add another waveform to the acquired waveform, i.e. I mean to say if the acquired waveform is a sine wave with 60 Hz frequency and amplitude of 8V peak-to-peak, I want to finally display a wave which is 8V peak-to-peak with sinusoidally changing freuency.
To be more clear...I want a sine wave with frequency = 60 Hz + 1*sin( 2*pie**t).
As cane bveen seen in my vi, I can extract the phase and magnitude of the original acquired signal.
Can anyone help me out with this...as I'm not able to figureout how should I proceed next.
Looking forward to hear soon,
Regards,
Rohit
Attachments:
test_analog.vi 162 KBYou'd probably want to use the DAQmx VI's instead of the Express VIs, when doing something more exotic. You can start by converting the existing Express VIs to code by opening their front panels and saving them as a VI.
Regards,
André
Using whatever version of LV the customer requires. (LV5.1-LV2012) (www.carya.nl) -
MacbookPro...what is speed when with iLife08 and Adobe CS3...?
I will be buying a 17"Macbook Pro next month and I know that it will ship with iLife08. But am also going to be purchasing Adobe CS3. So with all these graphics heavy programs, any thing I should be aware of in terms of speed, specifically if I am editing a movie in iMovie? or importing a quicktime movie into a Web page design? I'm also going to be getting iWorks to do presentations. Lots of graphics. Plus I will be doing a lot of work editing photos in RAW in Photoshop.
It's a big investment and want to make sure that it's going to help me with my work rather than cause frustration because editing a movie will take as long as it does now on my G4 Powerbook.
Do I need to customize the Mac when I purchase it so that it has whatever it needs to run faster? I don't want to have to do this after I've purchased it if I don't have to.
Thank you from a non-techie type person--so please, in layman's terms! Would appreciate it.RAM is very important for the tasks you mentioned, and the price Apple charges at the customization stage on their online store is obscene. Replacing the RAM on the MBP is very easy and I'll paste some links to help you decide whether you'll be up for the DIY install. And yes, you should experience a nice speed bump over a G4, even editing in HD.
http://www.macsales.com/
http://www.crucial.com/store/listparts.aspx?model=MacBook%20Pro%202.4GHz%20Intel %20Core%202%20Duo%20%2817-inch%29
http://docs.info.apple.com/article.html?artnum=303491 -
I have to measure differential signals (0 to 5 V level). Unfortunately the maximum working voltage of the analog input channel of NI 6115 S-serie - is +-2.5 V. What will happen? Will the performance of the NI 6115 decreases? And - can I get an error when I connect fast signals to - (!), because the inputs are pseudodifferential?
Hello matops,
I don't think you should be running into any type of problem trying to measure a 0 to 5 V differential signal using the NI 6115. The maximum working voltage for the negative input is specified at +-2.5 V, meaning that you can have a maximum common mode voltage of 2.5 V in your measurement system. However, the maximum working voltage on the positive input is +-11 V or +-42 V, depending on your voltage range. If you are going to be going above this limit, then you may want to reconsider your measurement setup as you could damage the hardware.
Though pseudodifferential signals are usually composed of a signal on the - input that is slow to change, the 6115 is specified at a maximum sampling rate of 10MS/s, and thus I think it is going to be OK to co
nnect a fast signal to these inputs (depending on what your definition is of a fast signal).
Hope this helps.
Jared A. -
Speed Issue with objectoutputstream and objectinputstream
Hi all,
I have serialized my resultset into a file on the harddisk and converted it back into resultset using below methods : -
public void writeRS(ResultSet pRs) {
try {
crs = new CachedRowSetImpl();
} catch (SQLException ex) {
Logger.getLogger(SerializeRecords.class.getName()).log(Level.SEVERE, null, ex);
try {
crs.populate(pRs);
} catch (SQLException ex) {
Logger.getLogger(SerializeRecords.class.getName()).log(Level.SEVERE, null, ex);
ObjectOutputStream outputStream = null;
try {
outputStream = new ObjectOutputStream(new FileOutputStream("c:/ABC.xml"));
} catch (IOException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
try {
outputStream.writeObject(crs);
} catch (IOException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
try {
outputStream.flush();
} catch (IOException ex) {
Logger.getLogger(SerializeRecords.class.getName()).log(Level.SEVERE, null, ex);
try {
outputStream.close();
} catch (IOException ex) {
Logger.getLogger(SerializeRecords.class.getName()).log(Level.SEVERE, null, ex);
public void ReadRS() {
ObjectInputStream ois = null;
try {
DataInputStream dis = null;
try {
dis = new DataInputStream(new BufferedInputStream(new FileInputStream(new File("c:/ABC.xml"))));
} catch (FileNotFoundException ex) {
Logger.getLogger(SerializeRecords.class.getName()).log(Level.SEVERE, null, ex);
ois = new ObjectInputStream(dis);
try {
ResultSet t_Rs = (ResultSet) ois.readObject();
try {
while (t_Rs.next()) {
System.out.println(t_Rs.getString("name"));
} catch (SQLException ex) {
Logger.getLogger(SerializeRecords.class.getName()).log(Level.SEVERE, null, ex);
} catch (ClassNotFoundException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
ois.close();
} catch (IOException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
} finally {
try {
ois.close();
} catch (IOException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
It Runs Fine with small resultset but when it became bigger likewise, suppose it is having 50,000 records then reading and writing taking too much time. Can i reduce it??? if yes, then please tell me how??Iteration with same data took 7 secondsIs that iterating over the original ResultSet or the one you fetched from the file?
And, if the former, again, what's the point? If fetching 50,000 records from the DB only takes 7 seconds why aren't you doing that? Why are you even contemplating writing them to a file and reading them back?
And if the latter, it is your processing that is at fault, not serialization, or buffering.
Can we set the buffer size of outputstream and inputstream ?? Sure, put a BufferedOutputStream between the FileOutputStream and the ObjectOutputStream, and similarly with BufferedInputStream. You can control the buffer sizes of both.
But I haven't yet heard what the actual point is. -
CV measurement with HP4275A and Labview
We are currently using HTbasic interact with HP4275A to do CV measurements. The HTbasic program occasionaly lockup. I wonder if anyone write VIs to do the same type of mesurement as HTbasic does. Please point me to where I can download VI example to do CV measurement.
Look on your LabVIEW Instrument Driver CD or download it here.
Message Edited by Support on 11-20-2007 02:45 PM -
How to measure current and voltage and rpm with daq device
i am measuring current and voltage and am wondering should i use shunt resistors or current sensors hall effect sensors. i have a pci 6221 and a scc-68 breakout box. what specifications or size should the shunt resistor/current sensor be or should i use another device to measure the currrent and voltage. do i need any other safety device between the resistors, current sensors and the scc-68 breakout box when measuring the current and voltage. will the daq card pci 6221 pick up a signal from the resistor. what terminals should the wires from the resistors and current sensors be connected to in the scc-68. i am using a proximity switch to measure rpm of a motor. should the proximity switch be 2 or 3wire connection. should it have an analog or digital connection and is a power supply required to power the proximity switch and should it have an npn or pnp connection
hello,
i was going to use a 20amp 50mv, or a 20amp 100mv current shunt and connect wires directly into the AI input terminals of the scc-68 from the current shunt would these be suitable. would current shunts such as these be suitable to use http://uk.farnell.com/elc/sh10020/shunt-sh10020-20a-100mv-1-class/dp/1319576 or http://uk.farnell.com/datel/3020-01098-0/shunt-50mv-20a/dp/1339338
is it ok to use either a current shunt or should a hall effect sensor be used such as this http://ie.farnell.com/honeywell-s-c/csla2cd/sensor-hall-effect/dp/1082269 . which of them would be more accurate or are both of them fairly accurate.
when i am measuring voltage can i connect two resistors between the positive and negative of the wires going to the battery and connect two wires from either side of the resistor directly into the analog inputs of the scc-68 and measure the 12-15 volts directly would the pci6221 and scc-68 be able to measure the voltage drop across the resistor.
i wanted to measure rpm also does it matter whether the proximity switch has 2 or 3 wires and should it have an analog or digital/frequency output for cponnecting to the scc-68 -
Hello,
I am using force/torque transducer by ATI Automation. It provides me with its own vi to measure and write the data of the 6 signals (3 axes Forces, 3 axes torques)
Following is my Ni system: -
cDAQ 9172 chassis: Slot 5 - NI 9401, Slot 6 - NI 9205, Slot 8 - NI 9237. (Excitation voltage to the sensor/transducer (0-5V) using 9237).
I connect the 6 signals from the transducer cable to channels ai0,1,2,3,4,5 in NI 9205(differential). The vi uses a calibration 6*6 matrix to finally display the calibrated voltage data.
Now, I wish to use the remaining availabe channels that empty in 9205, namely ai17, ai18, ai19 for other signal measurements.
ai17 channel is connected to Hall sensor that gives out a square waveform corresponding to the rotor rpm. ai18, ai19 is connected to rotor-motor power supply's voltage and current signal respectively.
But I am not able to access these 17, 18,19 channels from ATI company's vi. The vi loads the complete DAQ card (9205), uses only first 6 channels, hence the array data wire consists of only 6 channels. I can split these into 6 individual signals only.
If I use a separate DAQ task to read channels ai17,18,19, then I get the error that this channels are reserved for some other task. Please tell me how can I access all the remaining channels apart from the first 6.
I am attaching the vi here.
Steps to run the "MEASUREMENT main.vi" : -
Load calibration file:- FT8840.cal;
Load DAQ card: NI 9205
Load ctr0 of NI 9401 (I am using this counter for rpm measurement purpose, this is my addition to the actual vi)
Attachments:
DAQ - Copy.zip 574 KBThere's nothing I can do to help. I don't have your hardware to be able to modify your code and to set it up to make sure it runs properly. Most people on the forum probably don't either. This is where you'll have to put your programming and LabVIEW skills to work to solve your problem and make it run the way you want to. If you run into a specific problem and get stuck, then please post back.
-
How do I run a J-type thermocouple to the usb-6363 DAQ and program labview to measure temperature?
I have a usb-6363 DAQ and a J-type non-contact thermocouple that I am looking to connect and measure temperature through. However, the DAQ does not have any T/C inputs, which is needed to measure in the thermocouple temperature. I am connecting the thermouple to an analog input (+/-) and I am not looking to buy an amplifier, converter or any other hardware. I believe there is a way to program labview to read in the voltages of the thermocouple and convert it into accurate temperature readings. Any help/ideas?
Hello George,
This tutorial should step you through the basic process of configuring the device and connecting the thermocouple:
Tutorial: Connect Thermocouples to a Data Acquisition (DAQ) Device
http://www.ni.com/gettingstarted/setuphardware/dataacquisition/thermocouples.htm#Connecting a Thermocouple to Your Device
From there, there are a number of things you can do- I'd recommend taking a look at the LabVIEW shipping examples (Help>>Find Examples...) as well as the DAQmx getting started tutorials:
Getting Started with NI-DAQmx: Main Page
http://www.ni.com/white-paper/5434/en
At first glance, the 6363 you're using should have enough resolution to acquire usable data from a thermocouple- if you attempt reading raw voltages be sure that the acquisition range is configured for +/- 0.1V, though.
Regards,
Tom L.
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