Analysing short pulses

[Luis Villa]

I want to sample a short pulse ( from .1 to 5 msec) and I want to measure
the voltage (0 to 60 VDC) and current consumed (0 to 5A) The 5B series
dont' have these kind of ranges and besides they have a bandwidht of 10khz.
I bellieve I need at least 30ksamples/s to accurately measure this pulse. Is
there any kind of signal conditioning that allows me to see this pulse?

Thanks

LVilla

[markwysong]

The answer to your question is yes, but it resides on a different form factor than the 5B series. To attain those types of sample rates, your are going to need a Multifuntion I/O board (MIO) installed on a PC. To get the signal conditioning you want, you'll need an SCXI chassis (Signal Conditioning eXtensions for Instrumentation), and a conditioning card. I believe what you'll need is a current viewing resistor, and sample the voltage on that CVR. Therefore, you'll be able to see the max voltage that occurred and the current (you could use two separate channels configured as differential). This would definitely do what you want, as MIO scan rates can go as high as 1.25 Ms/S. However, keep the resolution in mind--there are 12 and 16 bit MIO boards.

Mark

[Luis Villa]

If you could please help me with my electronics concepts, what is a current
viewing resistor and how would that be connected? Does this have to do with
sensing voltage at both sides of the resistor to get a voltage drop
mesurement?
Thanks
Luis

"markwysong" wrote in message
news:506500000005000000D42A0000-986697009000@quiq.com...
> The answer to your question is yes, but it resides on a different form
> factor than the 5B series. To attain those types of sample rates,
> your are going to need a Multifuntion I/O board (MIO) installed on a
> PC. To get the signal conditioning you want, you'll need an SCXI
> chassis (Signal Conditioning eXtensions for Instrumentation), and a
> conditioning card. I believe what you'll need is a current viewing

> resistor, and sample the voltage on that CVR. Therefore, you'll be
> able to see the max voltage that occurred and the current (you could
> use two separate channels configured as differential). This would
> definitely do what you want, as MIO scan rates can go as high as 1.25
> Ms/S. However, keep the resolution in mind--there are 12 and 16 bit
> MIO boards.
>
> Mark

[markwysong]

A current viewing resistor (CVR) is any resistor that is in series with the unit that is drawing the current. Since V=IR (voltage = current * resistance), you can read the voltage across this resistor and figure out the voltage. The trick is that the resistance must be quite low compared to the resistance of the unit under test, such the UUT current draw isn't affected by the addition of the resistor. Therefore, a CVR is usually 1 ohm or less (but that means it also has to be of sufficient power--a 1 ohm resistor with 1 amp going through it has to be at least 1 watt).

Mark