Dynamic strain measurement

Sir,
My experiment involves the measurement of strain on the specimen on the application of torque.
I'm using SC-2043SG for the quarter bridge ,with an internal excitation of 4.13V.
The problem is that when i apply 1.5 Nm and 2Nm torque, both are showing the same strain, 243 microstrain.
Whereas in the digital multimeter they show .7mV and .9mV respectively.
The strain is supposed to vary , which is not happening for every 0.5Nm. The multimeter is showing a
variation of .1mV for every 0.5Nm increase in torque. But this is not being shown in the strain output. Only
when it reaches 3Nm it shows 486 Nm. But this remains the same even for 4Nm.
external signal conditioning is also not helping.

thanks for replying ,
The DAQ device i m using is PCI -MIO-16E4
The DAQmx Device driver version is 7.5 0f 1
im attaching the program i made for my application.kindly see through it
thanks a lot
Attachments:
indu new.vi ‏131 KB

Similar Messages

Can I measure dynamic strain with a SCXI-1531 and how steady is the excitation current?

I am looking at the possibility of using an SCXI-1531 module to take measurements from a single strain gauge. I am only interested in the dynamic content of the signal and so am considering using the constant current excitation method which does not require bridge completion. Is there anyone out there that has tried this or could advise me as to whether this module is suitable?
Having read the spec of the module, it looks promising except for the data on the excitation current which states:
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Thanks for any help.
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Hi CAS,
Essentially the excitation provided by the module will not allow you to acquire as you would like.
However, the good news is that you are able to disable the excitation provided by the module, and provide your own external excitation. You should then be able to acquire the signal using the SCXI-1531.
To disable the excitation in LabVIEW using DAQm, place down a DAQmx Create Channel.vi and then configure it for Strain measurements. Then you can create a control/constantto wire to the Bridge Information Terminal by right-clicking on the terminal and selecting control/constant. Within this cluster control/constant will be an enum element where you can specify the voltage excitation source to be external.
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Attachments:
Strain measure.vi ‏19 KB

Hi jujare,
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Configuring NI9219 for strain measurement

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I am trying to set-up a strain measurement VI using Labview. I am using NI 9219 module on NI cDAQ 9172 chassis. My strain gage is configured in a quarter-bridge arrangement and I have made strain gage connection accordingly (to terminals 3 & 5 in NI 9219). However, I do not understand what are TEDS terminals for and what to connect to those terminals. Can I use virtual TEDS for this? I couldn't find a virtual TEDS for NI 9219. Any information in resolving this issue would be highly appreciated.
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Solved!
Go to Solution.

Hi, the TEDS terminals are only for transducers, like a strain gauge, that support TEDS (Transducer Electronic Data Sheet). The TEDS standard is just the ability of a transducer to save information about itself in internal memory. This information includes things like calibration constants and dates, scaling factors, electrical characteristics, etc. It is stored in a standard template which can be read by computers and DAQ cards via those TEDS lines. For you application, you should just leave them unwired, and setup up your strain gauge normally.
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It looks like the driver you are using is supported by a third party. I took a look at the driver you are using and it has a couple of examples included with it. I would recommend taking a look at these examples as they are normally a good starting point for communicating with your device. Has anyone else used this device in LabVIEW?
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Sudden spike in strain measurement

Hi!
I have a PXI 1062Q Chassis, 8108 controller (Windows OS), one PXI 4472 module(Slot 2) & two PXI 4331 modules(Slot 3 & Slot 5). The test scenario involves measurement from strain gauges mounted on a plate which is subject to some impact. But when I try to acquire strain data in the quarter bridge configuration from all the 16 channels at 100 K sampling rate, I find that there is a sudden spike in the data apart from the one observed due to the impact (Please refer attached pics). This spike is seen at exactly the same instant across all the channels. The following are the settings used for strain channel acquisition.
Acquisition Mode :Continuous Samples
Sampling Rate :100K
Samples to Read :10 K
Maximum Limit :1.5m
Minimum Limit : -1.5m
Strain Configuration :Quarter Bridge I
Voltage Excitation Source :Internal
Excitation Voltage :2.5V
Gage Resistance :120
Gage Factor :2
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Attachments:
Data with spike_1.png ‏34 KB
Data with spike_2.png ‏36 KB

Shweta_JP wrote:
Hey Lynn!
It's just a 1 sample spike in the positive & negative direction. Could an electrical transient result in such a small duration spike??
Shweta JP
EMC spikes could be of any length....
A good software spike filter is the median filter, here a filter rank of +-3 should do the job...
Looking at your picktures it seems that they appear in a close relation to your trigger ...
Crystal_ball_mode: You wrote impact test.... is there some sort of solenoid/relay/inductive release involved ? Without snubber they can be a source for such spikes....
Spoiler (Highlight to read)
Greetings from Germany
Henrik
LV since v3.1
“ground” is a convenient fantasy
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Strain measurment and write to file with NI9237

Hopefully this lab view VI can help some of the novices like myself to acquire strain using the NI9237 and write to a file. The example VI available from NI "Cont Acq Strain Samples (with calibration)" is fine for sampling data and viewing on a chart, but you need to add your own elements if you want to logg data or write to a file.
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Attachments:
Cont Acq Strain-Qbridge-I-write to file-NI9237.vi ‏199 KB
Measure Strain.llb ‏238 KB

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I am trying to measure strain using SCC SG04, SC2345, and M series PCI 6221. The system is saying that it is not installed properly even though MAX is recognizing the devices. If anyone has set up a similar system could they please help out. Project deadline is getting very close and i am in a bad way

Dr. Imad wrote:
what is not installed properly ? the M card or the SC2345 ?
Once the card is installed, go to max and verify that you see it in Max. Once this is done
under
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right click---create new
select DaqMx SCC-connector block-----SC2345
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Dr. Imad wrote:
what is not installed properly ? the M card or the SC2345 ?
Once the card is installed, go to max and verify that you see it in Max. Once this is done
under
devices and intefaces
right click---create new
select DaqMx SCC-connector block-----SC2345
Then you configure the SC2345, Type, where SG04 is installed (J1....) etc
then you should be able to access it from LabView. You may want to use Daq assisitant first.
I have done as you recommended. The Daq board does show up in max. I have added the connector block and the strain module. That seems ok until i do a self test and it fails. It says in the error message that the device may not be working properly or is not properly installed. I have removed the whole system and reinstalled it only to get the same error message. In the device manager in windows 2000 it says that the DAQ card is working properly. When i go to the drivers tab it says that the driver provider is National Instruments but the date and version are unknown. It is not digitally signed. I have tried to install a driver for this namely NIDAQ7.3CD1.zip and NIDAQ7.3CD2.zip but this doesn't make any difference. The DAQ assistant didn't get it working either.

Dynamic strain measurement

Sir,
My experiment involves the measurement of strain on the specimen on the application of torque.
I'm using SC-2043SG for the quarter bridge ,with an internal excitation of 4.13V.
I'm using PCI-MIO-16E4 DAQ device.
The DAQ Driver used is NI-488.2 2.30
Measurement and automation explorer version is 3.1.1
The problem is that when i apply 1.5 Nm and 2Nm torque, both are showing the same strain, 243 microstrain.
Whereas in the digital multimeter they show .7mV and .9mV respectively.
The strain is supposed to vary , which is not happening for every 0.5Nm. The multimeter is showing a
variation of .1mV for every 0.5Nm increase in torque. But this is not being shown in the strain output. Only
when it reaches 3Nm it shows 486 Nm. But this remains the same even for 4Nm.
external signal conditioning is also not helping.
The automation explorer test run is always showing the same value about some -2.Its not at all changing inspite of the different toques applied
thanking u

Hi Neil,
I' ve used the traditional NI DAq version 7.4 0f0.
I had first connected to active strain gauge to a bridge completion circuit using 3 other SGs to form a full bridge. And then i have tried the method specifeid in the SC-2043-SG manual by following these steps.
SW1 for power supply
W1 and W3 For excitation
W8 for excitation
W2 for channel 0 input
W7 for HB for channel 0
placed the 120 Ohm bridge completion resistor in the socket R52
connected the lead wires from the active strain gauge to the +EX0 and +CH0 screw terminals.
I have connected nothing additional to what i have specified here.
I'm getting the same kind of output for both methods.
The outputs are fluctuating between values.
I don't know what is wrong in my configuration.Plz help.
i'm attaching the results of the torques applied in the order 1Nm,1.5Nm,2Nm,2.5Nm,3Nm,2.5Nm,3Nm,3.5Nm,4Nm
Thanks a lot
Attachments:
Document.rtf ‏873 KB

1520 Strain Measurement

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http://digital.ni.com/manuals.nsf/websearch/56E77CCD7B41AA8386256968005BBB73
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I am user of NI 9235 and my question is about measurement of strain gages. I attached the gages to material propertly and connect to nı9235 with embeded gage factor and ets. then I calibrate just with using button of calibration as attached pictures. I am not sure am I measure right data. I checked NI website, there is something mention about shunt calibration but it doesnt offered at NI9235.
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Attachments:
IMG_20150323_121018.jpg ‏5751 KB
IMG_20150323_121005.jpg ‏5594 KB

Hi,
Here is a National Instruments white paper http://www.ni.com/tutorial/7130/en/ that walks you through taking a strain gauge measurement. This should assist you in setting up your measurememnt. What about the data makes you think it is not measuring correctly?
I have found some other resources that may prove helpful http://www.ni.com/white-paper/11488/en/
http://forums.ni.com/t5/Signal-Conditioning/shunt-calibration-NI-9235/m-p/2460276
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Dynamic strain measurement

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