To measure resistances for larger values (ohms > 5) of resistance you can use a voltage divider.
HOWTO: [Novice] - Measure Resistance with a Voltage Divider - LabJack U12 - LabJack Forum
To form an equation for R2 you can solve 2nd equation Ain0 = 5 / (R1 + R2) for R2
Ain0 * R1 + Ain0 * R2 = 5
R2 = (5 – (Ain0 * R1))/Ain0
You can then graph the resistor value
To measure very small resistances you can use a Wheatstone bridge.
There are many websites on your favorite search engine to help with this method.
Assume you have 5K for R1 and variable resistor between 100-5000 for R2
To setup compucorder:
Paper -> recorder setup simple
A size, landscape, x axis = time, 1 analog channel, inch
Setup to read voltage
Voltage, adsi, -1 to 1V, Resistance, units = volt, max = 5000, min = 0, mult = 1, sample rate = 6, resolution index = 12
Then paper -> advanced menu -> recorder setup advanced -> control variable
analog expression
(5-(AIN0*5000))/AIN0
Unit type = resistance
From device = ohm
To plot channel = ohm
I did the above and saved a cds file using paper - recorder data save and attached to email
You can load the attached file the paper – recorder data load
If your R1 resistor is not 5K change equation to use correct R1 value.
If your voltage source is not 5V you would change the 5 in the equation to your voltage source. The VS from the compucorder is not quite 5 volts so you could measure that voltage with a dvm and update the equation.
If your range for voltage at input is > 1V you would change the 3rd answer in simple setup to -10 to 10V or in the advanced menu – control tab.
Note:
Resistance is not a very user friendly unit for your plot.
If you are measuring some other unit you would modify the equation to produce your user units of what your variable resistor measures (e.g. temp (°C, °F), light (LUX) etc.)