How do I use the 2300 with input voltages of greater than 50mV?

Submitted byglx25v onFri, 08/17/2018 - 17:29

The model 2300 supports the following signal types Thermocouple, PT100, DcmA, and DCmV. It is possible to use it with a DC voltage signal by using external resistors to drop the voltage signal.
The 2300 input needs to be set on the 0-50mV input range and a 470ohm resistor fitted across terminals 2 and 4. A resistor and potentiometer is then placed in series with the input signal. The input signal voltage determines the component values. The combination of a fixed value resistor and variable resistor allows the circuit to be calibrated to the applied signal.

The Value for the total series resistance is determined using the equation below.

Total Series Resistance = Input Voltage / 0.00010638

The series resistor value then needs to be split between the fixed resistor value and the variable resistor value. The value of the fixed resistor needs to be a value that when the variable resistor is at 0ohm the voltage across the 2300 input does not exceed 150mV. This can be determined using the following formula.

Variable Resistor (VR1) = Total Series resistance * 0.1