Input Capacitance of the USB 6008

Does anybody know the input capacitance of the NI USB 6008? Im creating a circuit that mimics a 10x probe whose design requires the value of the "oscilloscope" input capacitance, or in this case, the USB 6008 input capacitance.
Thanks so much!

With the low input resistance (144 kohms) the capacitance does not matter much. Any realistic value of input capacitance will have a time constant shorter than is meaningful for the device bandwidth.
Also note that the input impedance is terminated in about 1.4 V. See the circuit in Figure 7 of the User Manual.
Lynn

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Drive higer load with the usb 6008

Hi all,
I need to drive a small motor with the analog output of the usb6008 device ... connecting it directly doesn't seem to work.
Any suggestions how get it working??? what does the 6008 output?
My motor works on a AAA battery dricetly.
Thanks a lot

On Apr 23, 12:40 am, lav21 <[email protected]> wrote:
> Hi all,
>  
> I need to drive a small motor with the analog output of the usb6008 device ... connecting it directly doesn't seem to work.
>  
> Any suggestions how get it working??? what does the 6008 output?
>  
> My motor works on a AAA battery dricetly.
>  
> Thanks a lot
The analog outputs of the USB-6008 are only rated at 5 Milliamps per
channel. One suggestion for getting it to work is to use an emitter
follower to get more current to drive your motor.
Howard

Measure like the testpanel of the USB-6008

Hello,
I want to measure like the testpanel of the USB-6008. What is the right
example of the nidaq installation or what are the necessary c-functions?
The most c-examples quits with an error. So I don`t no what is the right. I searched in the dictionary "Analog In".
Thx Pellaeon

Hello,
you can find all examples for DAQ in C:\Programme\National Instruments\NI-DAQ\Examples\DAQmx ANSI C\Analog In\Measure Voltage.
Do not forget adding the include file and the library file to your project. That is described under NI-DAQmx C Reference Help. You can find this under Start->Programs->National Instruments->NI-DAQ-> NI-DAQmx C Reference Help and there under Getting Started--> ANSI C
USB-6008 is supported in NI-DAQmx 7.5 or NI-DAQmx Base. http://digital.ni.com/public.nsf/websearch/4D915A820A76823C862570390075EBF5?OpenDocument
regards
Peter K.
National Instruments

Seperate channels from the usb 6008

I am trying to read EMG signals into labview by using an USB-6008. At the moment I have tvo electrodes, and I have successfully managed to get both signals into labview. The problem now is that I want to seperate the signals. I want my program to listen for both signals, determine which electrode is active and perform specific tasks depending on the different signal.
Im sorry if this sounds confusing, I'm confused by it too.

Hi!
I may be wrong but you can create two separate tasks.
The limit is that they cannot run at the same time.
Depending on the application, the use of two tasks or a single "acquire all" approach can be the best option.
Regards,
Marco

Download just the USB-6008 driver (DAQmx) ?

Hi
Is there a way to download only the driver for my USB-6008 application
? Which means that I don't have to downlaod the installer with MAX and
support for different programming enviroments ?
Regards
Daniel

Hello Daniel,
When you install NI-DAQ, you are given the option to include support for multiple software programming environments, and MAX as well. You do need to install MAX and support for the API that you will be using, like LabVIEW 7.1 for example, but you can choose not to install support for everything else, like LabVIEW 7.0, CVI/LabWindows, .NET, etc.
-Alan A.

Is the USB-6008 controllable by Mathcad?

Can I use Mathcad calculation power to manipolate analog data converted
by a USB-6008 interface?
If yes, please indicate examples sources (if any).
Thanks .

Hi nonnog,
I don't understand very well what you want to do, but you have 3 possibilities:
if you have Labview you can acquire data from NI device and then you can use MathCad via ActiveX with Labview with the specific libraries downloadable at link: http://venus.ni.com/stage/we/niepd_web_display.DISPLAY_EPD4?p_answer=&p_guid=B799BC00B8835510E034080...
if you haven't Labview, you can acquire and save data from NI-USB device with 2 NI software ("VI Logger Lite" or "NI Data Logger" provided at no charge with driver) and then you can read these files from MathCad
if MathCad provides the possibility to create Macro or to call dll you can directly use driver functions to acquire data from the NI-USB device.
I hope this helps you.
MarcoC

Will USB-6008 DAQ be able to power and record voltage for UMS T5 tensiometer at the same time?

I would like to use my NI USB-6008 to provide power to my UMS T5 tensiometer (http://www.ums-muc.de/en/products/tensiometer/t5.html) as well as take readings from it, but I don't know if this is possible to do properly. The supply voltage for the instrument can be as low as 5V, which I can easily get from the dedicated +5V channel. I am able to power the instrument and connect it to an analog input on the 6008 and measure a voltage in differential mode. However, while reading the support literature for the instrument, I find the following:
"Potential data acquisition pitfalls: Because the pressure transducer is configured in a Wheatstone full bridge, the input voltage and signal mV output cannot be connected to the same reference (ground). Hence, the signal mV output can only be measured using a differential voltage measurement. Therefore, do not attempt to make a single-ended measurement of the pressure transducer mV output." (http://www.decagon.com/assets/Uploads/MeasuringUMSTensiometerswithnon-UMSControlandDataAcquisitionSystems.pdf)
My understanding is that the 6008 can take a differential measurement if I attach the signal "+" and signal "-" to the positive and negative analog input terminals. However, it seems that all of the Ground ports on the 6008 are grounded to the same reference, which would make my voltage measurement invalid according to the paragraph above. So my real questions is: if I attempt to record the voltage using one of the analog inputs on the 6008 in this way, is the measurement valid? Or do I need to find a separate power supply with a different reference ground to ensure that the measurement is accurate?

The specification sheet for that device is very poor. The manual is not much better. Companies which want to sell scientific equipment should publish decent data sheets or get out of business.
In section 3.4.3 General requirements the device is described as a "non-amplified bridge circuit." This information along with the bridge impedance should be in the specifications because it is essential to applying the device under any circumstances other than the nominal behavior at 10.6 V.
The answer to your question is this:
You can use it with the USB-6008. The 5 V power supply will result in output voltages slightly less than half (5/10.6) the voltages specified under nominal conditions. You can use the differential input mode on the USB-6008. The absolute input voltages will be about 2.5 V with the 5 V supply. That voltage is within the working range of the device. The differences will probably be less than 100 mV. The resolution of the USB-6008 on the +/-1 V range is about 0.5 mV so your pressure resolution will be around 1 % of full scale. The input impedance and termination voltage of the USB-6008 will introduce some errors. These may be on the order of 5-10%. I cannot predict much better without the missing bridge impedance specification. Those errors should be systematic and relatively constant. A calibration of the whole system - sensor and DAQ device together should allow you to compensate for much of that error.
Lynn

USB 6008 doubt on channel inputs

Hi,
I would like to control a switch on AC to AC converter circuit i.e.. I want to blank signal in circuit until user interested time. I am just worried about DAQ at channels that can I directly connect 240v AC to DAQ or in case if not possible, I would like convert this 240V to 20V because, I read the datasheet of USB 6008 says that allow only +or- 1 to +or- 20v. I strucked here and could not conclude my self. Is there any best converters out there in market for this application?

Definitely do not connect 240 VAC to your DAQ card!!!!!!
You could look at a relay that has contacts rated for your current and voltage of interest. You could also look at a solid state relay that can take a low voltage digital signal to turn on and off the high voltage AC signal. But you will have to see the requirements for the input coil of the relay, or the input of the solid state relay and see whether the USB-6008 can source that voltage and current. If not, you may need to look at another circuit such as a transistor driver to turn on and off the relay.

Simulated device capability for the NI USB-6008

I noticed that Nidaq 8.3, does not have simulated device
capability for the NI USB-6008. Is there any way of simulating
this device?
Thanks

Hello mmac,
Unfortunately, there is no way to simulate the USB-6008. If you would like to see this functionality in a future revision of NI-DAQmx, I would encourage you to go to the Product Suggestion Center and submit a product suggestion. R&D considers these suggestions when deciding on new features for development.
Best regards,

Error -10401 occurred at AI Group Config - in relation to USB-6008

I'm attempting to run a simple vi that uses AI Aquire Waveforms.vi to input voltage data that I have coming in from the USB-6008 DAQ. However, when I try running the program, I receive the error:
Error -10401 occurred at AI Group Config
Possible reason(s):
NI-DAQ LV: The specified device is not a National Instruments product, the driver does not support the device (for example, the driver was released before the device was supported), or the device has not been configured using the Measurement & Automation Explorer.
And I'm not sure how to fix it. In MAX, the device seems to be working properly and everyhting seems to work fine in the test panel, so I'm slightly at a loss. I'm running Labview 7.1, and installed NI-DAQmx 7.5 which came with the USB-6008.

Never mind. I'm new to Labview, and didn't realize that I could not use the traditonal Data Aquisition components with the USB-5008 (I didn't even realize that NI-Daqmx was different).

Temperature measurement usb 6008 with Thermocouple

Hi,
I am trying to measure temperature with type k thermocouple on USB 6008. I set max for measuring voltage, and got 0 voltage with noise. It would be appreciated if you can help me to wire up properly.
Cheers,

Hi,
You are doing the right thing by acquiring your thermocouple data as a voltage. From there, you can convert it to temperature data after the acquisition.
There are two configurations that you can use to connect your thermocouple to the USB device: Differential and Reference Single Ended (RSE). If you use differential, then you would connect one wire to the + channel and the other wire to the - channel. For example, to use AI 0, you would make connections to AI0 (+) and AI4 (-). If you use RSE mode, then you would connect one wire to an analog input channel and the other wire to ground. So for AI0, you would connect the + to AI0 and the - to ground.
More information about these connections is available in the USB 6008/6009 User Guide. Also, here are two links about the different types of configurations you can use as well as thermocouple polarity:
Field Wiring and Noise Considerations for Analog Signals
How Can I Determine What Kind of Thermocouple I Have and the Correct Polarity of Signal Connections ...
Regards,
Hal L.

Per-channel gain on USB-6008/6009?

Is analog gain controllable on a per-channel basis on the USB-6008/6009
DAQs? In other words, could AI0 be set to an input range of +/- 10V
while AI1 is set to +/- 1V?

Yes! You sure can set the range on a per-channel basis.
-Alan A.

USB 6008 power up inconsistent

Hi,
Now that I have read enough about the DAQ 6008 and know that the DIOs power up to 5V when it is connected to the USB. And, knowing that , I have worked around it. But, here is my problem. very random behavior occurs in that few channels dont power up and I disconnect the DAQ and connect it back; they do. This random behavior is affecting my system. Should I trust the internal pull up or should I myself pull the voltage up to 5V using an external 4.7k resistor?
Thanks!
V
I may not be perfect, but I'm all I got!

Hi VeeJay,
I just looked through the USB-6008 user manual and specifications (found here) on page 23 it states:
At system startup and reset, the hardware sets all DIO lines to
high-impedance inputs. The DAQ device does not drive the signal high
or low. Each line has a weak pull-up resistor connected to it.
This means that the default power up start would have each of the digital lines set for input and pulled up to 5V internally. You shouldn't need an external pull up, though you can see on page 22 you can definitely add one.
My question is what ports are not at 5V when you plug the 6008 in the first time? Also, is it possible that some of the lines you have connected to the digital ports are driving the lines low? Do you notice this behavior when you don't have anything connected to the 6008?
Eric S.
AE Specialist | Global Support
National Instruments

Controlling direction of DIO ports of USB-6008

How does a person control the direction of the DIO ports in the USB-6008? And how does one then receive a signal (if dir = in) and send a signal (if dir = out)? Sorry, I'm new to Signal Express.

Hi Tim,
In general, the direction (input or output) depends on the type of step you define in Signal Express. As you can see, when you see the Add Step options, you have the option to both Acquire Signals (dir = in) and Generate Signals (dir = out).
Hope this helps!
~kgarrett
Applications Engineer
National Instruments

DC motor closed loop control through labview using usb 6008

Hello
i am doing a project in which i want to control the speed of a DC motor (PID control) through labVIEW 2010. I am having a DC motor, a drive unit that regulates the voltage to the motor by getting analog voltage from 0 to 3.3V ( it can be used for both directions) and i also have a NI usb 6008 board. The problem is that i can't feed the usb 6008 with the digital signal from my hall effect speed sensor. Is it posible with this setup to control the motor?? I can also try to use the pulse as analog input and trasform the frequency into rpm's. Then i am thinking of generating an analog signal to feed the motor drive. If you have any further suggestion of a probably better hardware setup would be more than helpfull to me.
Sincerely
Jason Chaloulos

Hello Michael
Thanks for the reply. I came across those topics before and all of them are trying to generate a PWM signal as output i want to use just an analog signal output so timing on the output is not that important i guess. i am struggling on getting the frequency from the digital input signal that my hall effect sensor generates. Since the maximum speed of the motor is 3000 rpm and with my tooth wheel the maximum output frequency of the sensor will be 300Hz which i see its way less than the limitation of my ni board. Is there any tutorial documentation that might help me with this one ? Thank you in advance.
Kind regards
Jason

Input Capacitance of the USB 6008

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