Any limitations on the number of USB-6008 I can use on one computer?

[hellolv]

Hi,

I need the temperature rating(55 degrees C) on USB-6008 and 12 channels of plus/minus 20V range(Analog inputs) to operate.

Can I run 3 or more USB devices on one computer?   Has it ever been done before or there is any limitations on this application?

My sampling frequency is going to be 1kHz per channel.



Thanks.

hellolv

[G1L]

i think it wouldn't be a problem, you can connect up to 254 USB devices to a single computer

[Dennis_Knutson]

Well, you might have a problem with the +/-20 volt signals since the USB-6008 has only a +/-10 volt range.

[AnalogKid2DigitalMan]

Dennis-

I think the 6008 can do +/-20V in DIFF mode. What college did you go to?

-AK2DM

[James_R]

Analog

the USB-6008 says -10v..10v as maximum range for Analog Input in the datasheet

[AnalogKid2DigitalMan]

Each input is limited to +/-10V from ground in DIFF mode, so:

(-10V) - (10V) = -20V

(10V) - (-10V) = +20V

Thus +/- 20V range. Unless I am totally missing the boat here.

I looked up the manual, it tends to agree (portions copied/pasted here):

https://www.ni.com/docs/en-US/bundle/usb-6008-6009-feature/page/introduction.html

The differential input mode can measure ±20 V signals in the ±20 V range.

However, the maximum voltage on any one pin is ±10 V with respect to

GND. For example, if AI 1 is +10 V and AI 5 is –10 V, then the

measurement returned from the device is +20 V.

Input range

Single-ended ................................... ±10 V

Differential...................................... ±20 V, ±10 V, ±5 V, ±4 V,

±2.5 V, ±2 V, ±1.25 V, ±1 V

Working voltage..................................... ±10 V

[Dennis_Knutson]

Kid, you're right. I went by the summary of specifications at https://www.ni.com/en-us/support/model.usb-6008.html. The manual does indeed say that +/-20 is the max for diff mode.

Now, can anyone explain why diff mode supports so many different range settings but with single ended, you are limited to only one?

Message Edited by Dennis Knutson on 03-27-2007 10:39 AM

[AnalogKid2DigitalMan]

Sometimes you have to be careful in the quick product overview pages, such as this one that showed negative resistance, capacitance and inductance ranges, I now see it has since been corrected recently:

http://forums.ni.com/ni/board/message?board.id=250&message.id=28786

For the single ended restrictions on the USB-600x, I can only guess it may have an oversight in the programmable gain amplifier programming?