What is a Load Cell Output Calculator?
A Load Cell Output Calculator is a specialized engineering tool designed to predict the electrical signal produced by a strain gauge load cell under a specific weight. Load cells convert mechanical force into a proportional electrical signal, typically measured in millivolts (mV). Because this signal is extremely small, understanding the theoretical output is critical for calibrating signal conditioners, PLCs, and digital indicators.
The Formula Behind the Calculation
To determine the output signal of a load cell, you use the following physical formula:
Output (mV) = [Excitation (V) × Rated Output (mV/V) × Applied Load] / Rated Capacity
For example, if you have a 10V excitation voltage on a 2.0 mV/V sensor with a 1000kg capacity, and you apply a 500kg load, the math would be: (10 * 2.0 * 500) / 1000 = 10mV.
Key Terminology Explained
Excitation Voltage: This is the supply voltage provided by the controller or weighing indicator. Common values are 5V, 10V, or 12V. Higher excitation can provide a stronger signal but may lead to thermal drift.
Rated Output (Sensitivity): Usually expressed in mV/V, this is the amount of signal the cell produces for every 1 volt of excitation when loaded to full capacity.
Rated Capacity: The maximum weight or force the load cell was designed to measure accurately. Exceeding this can damage the sensor.
How to Use This Tool
1. Enter the Excitation Voltage being supplied by your instrumentation.
2. Input the Rated Output (found on the load cell calibration certificate).
3. Enter the Rated Capacity of the sensor.
4. Enter the current Applied Load you wish to test. The calculator will immediately provide the expected millivolt reading for troubleshooting or setup.
Frequently Asked Questions
Why is my measured output different from the calculated output? Differences often occur due to cable resistance (voltage drop), tare weights (mounting hardware), or physical misalignment of the load cell.
Can I use different units? Yes, as long as the Rated Capacity and Applied Load are in the same unit (e.g., both in kg or both in lbs), the ratio remains the same and the result will be accurate.