Load cell millivolt (mV) output calculator

What is a load cell?

A load cell is a sensor that measures weight or force. It converts that force into a small electrical signal, usually expressed in millivolts per volt (mV/V). The most common type of load cell uses strain gauges and is widely used in weighing systems.

What is Load Cell Output in mV and Why is it Important?

Load cells convert mechanical force (weight) into a tiny electrical signal, typically in millivolts (mV). This signal is proportional to the applied load and must be amplified before being read by controllers or transmitters.
Understanding and calculating this signal helps ensure:

• Accurate weight readings
• Reliable analog signal conditioning
• Proper configuration of PLC/DCS analog inputs
• Detection of load cell or cable faults

How can I calculate the expected millivolt reading of my scale?

To determine a load cell’s millivolt (mV) output, However, the following details are still necessary.  Such are 

What is the sensitivity of load cell mV V?

Sensitivity of the Load Cell (mV/V):

The sensitivity of a load cell refers to the change in millivolts produced by the load cell per unit change in applied load. It is usually provided by the load cell manufacturer and is expressed in millivolts per volt (mV/V). The sensitivity value helps us determine the relationship between the applied load and the millivolt output.

Excitation Voltage (V):

The excitation voltage is the voltage supplied to the load cell for proper operation. It is typically specified by the load cell manufacturer and is given in volts (V). The excitation voltage is necessary for converting the mechanical force exerted on the load cell into an electrical signal.

Applied Load(Kg):

The applied load refers to the weight or force you place on the scale for measurement. It can be in various units such as kilograms, pounds, or Newtons, depending on the load cell’s specifications. It’s important to ensure that the units of the applied load match the sensitivity of the load cell.

Scale capacity(Kg):

The full capacity of a weigh scale refers to the maximum weight that the scale is capable of measuring accurately and reliably. It represents the upper limit of the scale’s weight range, beyond which it may provide inaccurate readings or risk damaging the equipment.

Zero offset mv output (mV):

Zero offset mV output from a scale refers to the electrical signal produced by the scale’s load cells when there is no weight applied. It represents the baseline voltage level, allowing for calibration and accurate measurement of weight by comparing the difference between the zero offset and actual output.

How to Measure or Verify these Inputs

• Sensitivity – Found on the load cell datasheet or engraved on the body.
• Excitation Voltage – Supplied by the weighing transmitter or PLC; verify with a multimeter.
• Zero Offset – Measured with no load using a voltmeter across the load cell output terminals.
• Applied Load – Use certified test weights or known reference mass.

Scale Capacity – Also available in datasheets or nameplates.

Formula for the calculation

Use the following formula in order to determine the millivolt reading that should be expected:

How do you calculate mV V in a load cell?

Example calculation

To calculate the expected millivolt reading, follow these steps:

The expected mV increase = (Applied load/Scale capacity) X Sensitivity X Excitation voltage

The actual mV output reading = expected mV increase + Zero offset mV output 

How do you determine load cell sensitivity?

Step 1: Determine the Sensitivity:

Consult the load cell’s datasheet or manual to find the sensitivity value. For example, let’s assume the sensitivity is specified as 2 mV/V.

Step 2: Determine the Excitation Voltage:

Check the load cell’s specifications or manual for the recommended excitation voltage. Suppose the excitation voltage is given as 5 volts (V). Also this can be physically measured with multimeter.

Step 3: Measure the Applied Load:

Place the test weight on the scale and measure the applied load using a calibrated instrument. Ensure that the units of the applied load match the sensitivity of the load cell. For instance, let’s assume you place a 1000 kg test weight on the scale.

Step 4: Find the Scale capacity:

Consult the load cell’s datasheet or manual to find the scale capacity. For example, let’s assume the scale capacity is 5000 Kg.

Step 5: Zero offset mv output:

The weighing control display unit may show the zero offset mV output signal from a scale. Additionally, it can be physically measured using a multimeter from the average card output of a load cell or from the load cell input signal terminal in the weighing control display unit. For example, let’s assume the 1.5mV

The expected mV increase= (Applied load/Scale capacity)X Sensitivity X Excitation voltage

= (1000/5000) X 2.00 X 5.00

The expected mV increase = 2.00 mV

The actual mV output reading = expected mV increase +Zero offset mV output 

The actual mV reading = 1.5 + 2.00 

The actual mV reading= 3.50 mV

So the load cell output from the weighing scale will be 3.50 mV

Load cell millivolt (mV) output calculator 

The following calculator was used to determine the Load cell millivolt (mV) output when placing the test weight on the weighing platform during weighing system troubleshooting.

Template for Troubleshooting check list of load cells

Refer the below link for the Template for Troubleshooting check list of load cells in industrial weighing system

Tips for Troubleshooting Load Cell mV Output

• Check for loose wiring or shield grounding issues.
• Compare measured vs. expected mV output to detect drift or internal damage.
• Ensure the excitation voltage is stable and within spec.
• Don’t forget to consider temperature effects or mechanical mounting misalignments.

Refer the below link for – How to do troubleshooting of load cell

FAQ – Load Cell Millivolt (mV) Output

What is mV/V in a load cell?

mV/V stands for “millivolts per volt.” It tells you how much signal (in millivolts) the load cell produces for each volt of power it receives when fully loaded.
For example, a 2 mV/V load cell powered with 5 volts will produce 10 millivolts at full load.

How do I calculate a load cell’s mV output? 

To calculate the expected millivolt output of a load cell:

• First, calculate the load ratio:
  Load Ratio = Applied Load ÷ Full Scale Load
  Example: If you apply 500 kg to a 1000 kg load cell, the ratio is 500 ÷ 1000 = 0.5.
  
• Next, multiply this ratio by the load cell sensitivity (in mV/V) and the excitation voltage (in volts):
  Output (mV) = Sensitivity × Excitation Voltage × Load Ratio
  Example: 2.0 mV/V × 5 V × 0.5 = 5.0 mV

What is the mV output of a load cell? 

The output of a load cell is rated in millivolts per volt (mV/V). This rating tells you how many millivolts the cell outputs at full rated load for each volt of excitation supplied.
For example, a 2 mV/V load cell powered with 3V excitation will produce 6 mV at full load.
Most standard load cells have a sensitivity between 1 mV/V and 3 mV/V.

How do you calculate load cell output voltage? 

You can calculate the output voltage using this formula:
Output Voltage (mV) = Excitation Voltage × Sensitivity (mV/V)

Example:
If the excitation voltage is 2.0 V and the sensitivity is 0.7 mV/V, then
Output = 2.0 × 0.7 = 1.4 mV (at full rated load)

For partial loads, multiply the result by the load ratio (applied load ÷ full load).

How can I check the mV output of a load cell? 

To check the load cell’s output:

• Ensure the direction of force is correct and matches the intended load direction.
• Connect a digital multimeter (DMM) to the positive and negative signal wires of the load cell.
• With no load applied, the reading should be close to 0 mV (usually within ±0.5 mV).
• Apply a known weight gradually. You should see a corresponding increase or decrease in the mV reading.

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