Electroscope connected to Labview

[hacklord]

I am working on an electroscope sensor that will connect to a 6211 with Labview.  I have a breadboard.  Does anyone have a real simple schematic of an electroscope that will connect to the 6211 with Labview?  Thank you.

[aeastet]

You are going to need to know a lot of information. The manufacturer, the model number, interface etc.. Once you have all of this you will need to develop a communication protocal or read directly from the sensor if possible. If you can read from the sensor then you will need the pinout in order to know how to hook it up to the breakout board.

That is way to general of a question to ask how an electroscope is hooked up.

[hacklord]

I am just interested in the sensor part.  I have tried some simple circuits from the web using a FET.  Sometimes I got a reaction.  I do not know if I am doing it right , therefore  I request other opinions and ideas.  Any schematics you suggest are appreciated.

[RavensFan]

Unfortunately your reply didn't answer any of the questions that aeastet asked.  It is hard to give help if you don't give any information on the make/model of this electroscope.  Is there a weblink to a manual for it?

[hacklord]

Check out these Url's.  Where would I hook the connectors to the 6211 ? 

 http://www.eskimo.com/~billb/emotor/chargdet.html

[RavensFan]

It looks like the LED is essentially the indicator on this device.  With a high enough positive voltage it lights, too low or negative, it doesn't.  So I would use an analog input channel on the USB-6211 wired across it.  I would use differential mode, but single ended mode may work just fine also.  So AI0 + to the + side of the LED, AI0 - to the - side of the LED.  If that doesn't work, then I would remove the LED and try again.

[johnsold]

If you want to measure the charge rather than just indicate that some charge was there, insert a resistor in series with the LED.  Then the voltage drop across the resistor will tell how much current is flowing in the LED and will be an indication of how much charge has been applied to the gate of the FET.  The exponential voltage current relationship for the diode makes it difficult to extract any useful information without the added resistor.

Lynn