Accelerometers with SCB-68

Hello,
I am running a test with two accelerometers to measure vibration in a cantilever.
I am using the SCB-68 connector block. The accels tie in to the connector block....1 line has signal, the other is a ground. I have one accel tied in to Channel 0 and the other tied in to Channel 1.
When I run the test, I get the impulse spike from the accel on the hammer. The hammer has an accel in it and is used to impart a force onto the beam. The other accel is mounted on the beam and it provides the typical transient response curve. So far, so good...
The problem, however, is that the curve (when there are no inputs) is not flat, but rises slightly, as if the units are not grounded properly.
Has anyone seen this or offer a suggestion? I believe all the connections are set up properly.
Thanks!

I have used the SCB-68 with accelerometers in the past and did not notice this type of behavior. However, I also used the DAQ card in differential mode instead of single ended. You may want to try that to see if it solves your problem (assuming you are not already doing so). You can still tie one of your inputs to ground, if your sensor needs this.
You have probably already done this, but check to make sure your connectors are clean and the input wires are clamped well. I have been burned by accidentally clamping the wire insulation, pinching through it, and getting a flaky contact.
This account is no longer active. Contact ShadesOfGray for current posts and information.

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PCI 7830R series DAQ card with SCB 68

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Attachments:
Digi.vi ‏37 KB
Digi (H).vi ‏121 KB

PCI 4351 cjc with SCB-68

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Hello Craig,
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Using the SCB-68 in a CA-1000, what terminal numbers do I connect:
1.Type K connector panelette
2.BNC connector panelette
3.Dual 9-pin D-sub connector block
I would greatly appreciate any assistance with this question and any other advice that may help...we are new at this thing and would like to advance the installation as quickly as possible. Thanks! Scott.

Hello Scott,
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If you are unable to determine the information you need from analyzing the manuals, then respond back with information on what type of signals you will be trying to measure (i.e. analog voltage, tem
perature, digital, etc.) and I'll see how I can help.
Best of luck.
Jared A

Using rotary encoder with SCB-68

Hello,
I am using an Omron rotary encoder (E6B2-CWZ6C incremental) on a SCB-68.
I found a bunch of examples that allowed me to wire:
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Hi Ben
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Regards,
Luca
Regards,
Luca

PC freeze after booting with SCB 68 (connection box) connected

My PC hang immeaditely after boot when my signal box SCB 68 is connected. What can cause this error?
Can it be due to some driver problems? Wrong cable? Others who had same problem?
Rune
Test technican

Rune:
Sounds odd to me. Have you tried disconecting pieces of hardware incrementally and reboot to try and isolate the cause? Of course power down the PC while disconnecting hardware.
1. Disconnect any devices/wiring on the SCB-68
2. Disconnect the SCB-68 from the cable
3. Disconnect the cable
4. Remove DAQ card from PC.
If you still hang up during boot, then I would say it is a software issue. Let us know how 1-4 goes.
What operating system, LV and DAQ versions are you using?
~~~~~~~~~~~~~~~~~~~~~~~~~~
"It’s the questions that drive us.”
~~~~~~~~~~~~~~~~~~~~~~~~~~

Some wire connection problem for SCB-68 usage in measuring voltage

I am using FPGA 7831R along with SCB-68 to measure some voltage from my monitor terminal from my motor. When I measure the voltage between the monotor output and GND using a multi-meter the measurement is very reasonable and it can be changed when motor speed is changed. However, When I use FPGA input function to measure the monitor output(corresponding AI0 on SCB-68), the number displayed on the scope is always 10. The displayed value from GND is also 10(corresponding AI1 on SCB-68), so when I substract AI0 from AI1 the value is zero. Did I do something wrong in wire connection.
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Hi shuishen1983,
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Jared S.
Applications Engineering
National Instruments

How to measure a current signal with NI 6211?

How to measure a current signal with NI 6211?

Hi Clecio,
This is a charge accelerometer. It is different from the IEPE accelerometers that outputs a voltage signal.
You need a charge amplifier. Then according to the charge amplifier output we can select an appropriate module to measure the signal.
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Best Regards,
Rodrigo Schneiater
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If this information was useful, please click in the 'KUDOS!' beside.

Adding 2 ADXL335 accelerometers to NI 6009 DAQ. Conversion from voltage to acceleration.

Hello,
I am working on a continuous data acquistion project using 2 ADXL335 accelerometers with the NI 6009 DAQ. Ideally, I would like to measure them as differential, but there are only 4 differential ports on the 6009, so I would be 2 axis short. Since there are 6 axis I am looking to measure, I have set each axis as an RSE port a0-A5.I am working with Visual C++ and coding in C. I have been working with the VC_TDMS_ContAcq_IntClk example code to export the data to an excel spreadsheet, which works fine. However, since the DAQ cannot read the ADXL335 device as an accelerometer, I have each axis set as a voltage source. Therefore, my exported data to Microsoft Excel are data points that are voltage (v) and not acceleration (g). My voltage data points for each axis at rest with no vibration vary anywhere from 1.3 - 1.9 (see attached). a0 = X1, a1 = Y1, a2 = Z2, a3 = X2, a4 = Y2, a5 = Z2.
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Best Regards,
Scott
Attachments:
data.JPG ‏179 KB
graph.jpg ‏183 KB

You should decouple /filter the supply and analog output voltages (analog) and you should use some digital filtering...
If you look at fig.1 of the ADXL335 datasheet , what values did you use for the capacities? How close is the C_DC to the MEMS ?
What is the maximum frequency you want to measure?
How did you provide the power to the sensor, how did you exactly connect the sensor (all used wires and shields)
Since these sensors provide DC signals, you can easily 'calibrate' your sensors by measuring the output voltage for each axis at -1g and +1g , the rest is simple math
and keep in mind that the sensitivity has a range (so try to calibrate) and is ratiometric to the supply voltage ...
And keep in mind that you have an offset at the output voltage, so your scaled value of 5 makes sense
Greetings from Germany
Henrik
LV since v3.1
“ground” is a convenient fantasy
'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'

Simple device control with LabVIEW 7

Hello,
I have been a LabVIEW user for about 6 months and feel very comfortable with the "basics." I have used V7.1 with SCB-68 connectors as well as SCXI-1100 systems. I have written vi's that take voltage in from a variety of devices and produce good results.
For the next phase of my "education" I would like to build simple vi's that do things like turn motors or pumps on and off. After that, I would like to be able to use a vi to say, adjust the speed of a DC motor.
Are there vi's or links at the NI site that can help. I have searched the site extensively but have not found anything that propels the user from the passive analog input stage to using LabVIEW to interact with devices in the lab.
Please advise.
Thanks!

Unless you're using the SCXI-1600 to drive the SCXI system, you should
have a DAQ card that has a couple analog outputs on it. If you do have
have the SCXI-1600, you'll need to get hold of a DAQ card that has
analog out's on it. Check out NIs M Series of cards or the SCXI analog output cards.
Once you have something that generatea a voltage, open the Example
Finder in LabVIEW (Help>Find Examples) ans double click through
"Hardware Input/Output>DAQmx>Analog Generation>Voltage" and
you'll see several examples showing you how to create a voltage. These
examples all have the source code included so you can see how
everything is done. Use then as a starting point and save them
somewhere else if yo modify one.
Ed
Ed Dickens - Certified LabVIEW Architect - DISTek Integration, Inc. - NI Certified Alliance Partner
Using the Abort button to stop your VI is like using a tree to stop your car. It works, but there may be consequences.

SCB 68 connections

Dear Sir
I am using NI PCI 6281 along with SCB-68. I want to collect data from a sensor which has BNC connector. My SCB 68 has no BNC port and I can only connect bare wires. What I should do? If I remove the BNC plug from the sensor wire and connect bare sensor wires to SCB 68 then will it be OK? or it will effect on the measurement?
Kind Regards
Urfee
Solved!
Go to Solution.

You may get a little more noise when going through the connector block than you would if you had a direct BNC connection on the DAQ. But it shouldn't be enough to matter. I would just cut the end off of the BNC cable to connect the signal and ground in the terminal block.
But if you are really worried about it, NI does have some DAQ boards with BNC connection. I haven't looked in a while, but they tend to be on the high end.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines

Problems with execution of software trigger in a ni-9233 module on C-rio 9104

Hi, i'm creating a project for vibration measurements of 4 accelerometers with c-rio 9104 and Ni-9233 module. I need to execute a trigger event (start the signals acquisition when signal crosses a trigger level). Few time ago I used NI- 9233 module with USB connector and I found an exemple that was perfect for my application (<link no longer exists>). Now I tried to modify this VI for make it compatible with FPGA system but SW_trig VI doesn't work. I thought I have a problem when I call FIFO in SW_trig VI because I called it in the Host VI.Is it right? I need help
Thanks
MATHB
below i listed VIs screenshots
Attachments:
Host (PC)2 vi.jpg ‏289 KB
SW_trig.JPG ‏197 KB

Thanks for your post. FPGA and CompactRIO add some great capabilities, yet we also need to think about them a bit different.
To make things easier, we developed this reference example, which we ask you to consider:
http://zone.ni.com/devzone/cda/tut/p/id/9196
For the trigger - a tachometer for example, we also have a trigger VI that can be used in FPGA
http://zone.ni.com/devzone/cda/epd/p/id/2326
For the RT side, our Sound and Vibration Measurement Suite also has tachometer trigger VIs and angular alignment VIs that might be helpful.
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Preston Johnson
Principal Sales Engineer
Condition Monitoring Systems
Vibration Analyst III - www.vibinst.org, www.mobiusinstitute.com
National Instruments
[email protected]
www.ni.com/mcm
www.ni.com/soundandvibration
www.ni.com/biganalogdata
512-683-5444

Z4 report Foreign trade regulations - S_ALR_87012405

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I was wondering if any of you could give me some hint of why Z4 report Foreign trade regulations - S_ALR_87012405 does not show any data.
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Thanks in advance for your advice
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The reason of report RFAWVZ40 does not display the results seems to be
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If the selection option for "Do not report st. cent. bank i" is empty,
the system classifies all state central bank indicators as not
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Full information about DAQmx Task Name - How get?

Labview 7.1 (information required for solve problem)
I put in my application a DAQmx Task Name for fast configuration but i want put all information about task in a txt or spreadsheet file. But in Labview 7.1 haven't VIs like (http://zone.ni.com/devzone/cda/tut/p/id/3079):
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I'm using Analog Input (Voltage and Accelerometers) with several configurations and I need register all data of configuration to re-execute in the future or know about how acquisition data were gotten.
I think that solve is in property nodes(DAQmx Task, DAQmx Channel, DAQmx Timing), but I believe will be hard work to make. Somebody has this working?
Leonardo de S. Cavadas
Maintenance Engineer and Inspection - Bureau Veritas do Brasil
Engineer Metallurgist with emphasis in Advanced Materials
Technologist in Computer Science

Sorry about that, I haven't checked if they were made only for LV 8 and later. Attached is a zip file with all the VIs converted to the version 7.1.
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Best Regards
Andre Pereira
Attachments:
DAQmxTaskInfoQuery.zip ‏586 KB

Count the number of Pluses Generated

we are using the pxi-6602(counter/IO) along with SCB-68.
the problem we are encountering is that,we want count the
number of pulses generated.
we are using the counter0 and generating the
pluse, using the example VI Genrate Finite pulse(TIO).VI
which we are able to capure at the CTR0-out.
we want to count the number of pulses generated at
CTR0, so we have connected to the gate of CTR1
and we are running the example vi Measure Pluse NI(TIO)
we are not able to count back the number of pulses generated.
can any one guide us ....
are we heading in the right
1)is it possiblt to count and measure the number of pulse generated.
2)is it neccessary to specify the PFI line in the measuring/counting.
3)output of one counter is connected to gate of the other counter to measure. is it right
4)since this is the first time we are using counter/timers, please guide us, about connecting the
out and source and gate in scb-68.
thanking you
rags

I'm not at a LV PC now, so I can't look at the examples you mentioned. However, the primary problem is that when you generate a finite pulse train on Ctr0, the DAQ driver makes use of Ctr1 to control the # of pulses generated by Ctr0.
Because you have a 6602, you can simply measure the # of pulses with any of the other 6 counters on board. Ctr1, the one you might naturally think to use, is the only one that won't work.
The method will depend on whether you're using traditional NI-DAQ or DAQmx. The example names sound like traditional NI-DAQ, so the simplest thing is to actually wire from Ctr0 output to your measurement Ctr's Source input. Each of the Ctr's has a different PFI pin as its (default) Source input. Summarizing your questions:
1. Yes it's possible to measure # of counts generated by Ctr0 with any Ctr EXCEPT Ctr1. (Note that if you generated continuous pulses with Ctr0, you could then use Ctr1 to count them).
2. It's possible to specify the PFI line for counting pulses. If you physically wire to the default Source input, it won't be necessary.
3. Output of one counter should be connected to the SOURCE of another counter.
4. Ctr0 Out should be wired to, say, Ctr2 Source. Don't have hw here to be able to identify pin #'s.
Final note: under DAQmx, you wouldn't need any wiring. You can programmatically tell any measuring counter to count the edges on any other pulse-generating counter.
-Kevin P.

Accelerometers with SCB-68

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