Using the Instrumentation Amplifier with a Gas Chromatograph
If your voltage readings are noisy, you should connect the Earth ground of the Gas Chromatograph to the black post on the end of the Instrumentation Amplifier box where the sensor cable is located. Connecting the Earth ground in this way should reduce or eliminate any electronic noise.
Also, keep in mind that Logger Pro software and LabQuest App both have Peak Integration tools that can be used to integrate and quantify GC peaks. Once you have collected GC data, you can simply choose Peak Integration from the Analyze menu. On this dialog, you can select and integrate peaks one at a time.
Using the Instrumentation Amplifier as a Current Meter
The Instrumentation Amplifier can be used to monitor current instead of voltage. By placing a resistor between the terminals, the voltage amplified becomes proportional to the current according to
I = (V/G)/R
where V is the voltage read, G is the gain setting of the amplifier, and R is the resistor value. To monitor current in a circuit, you want to choose a small resistor value; for example 0.1Ω or 1Ω resistor with a rating of at least 1W.
For monitoring a current output device, you will need to choose a termination resistor that is appropriate for that device (call for details or consult the manufacturers specifications). For best accuracy, perform a calibration using an open circuit and a known current source. One of the Vernier Current Probes can be used for this application.