The mV/V value found in load cell datasheets indicates the nominal output signal produced by the load cell per each volt of excitation at full capacity. This value is not the capacity; it is the electrical sensitivity of the Wheatstone bridge. When selecting an indicator, transmitter, or measurement card, the signal level must be calculated correctly.
What does mV/V mean?
The “millivolt/volt” ratio is a ratiometric expression. For example, a load cell with a sensitivity of 2 mV/V produces approximately a 20 mV net signal change from zero to full capacity when powered with 10 V. If the same cell is excited with 5 V, the full-scale signal will be approximately 10 mV.
How is the output signal calculated?
Basic calculation: full-scale output = sensitivity (mV/V) × excitation voltage (V). Under partial load, this result is multiplied by the ratio of the applied load to the capacity.
Example: A cell with a capacity of 1000 kg and a sensitivity of 2 mV/V is powered with 10 V. At full scale, a 20 mV signal is expected, and at 500 kg load, approximately a 10 mV signal is expected. The actual value may be affected by nominal tolerance, zero balance, and system losses.
Difference between 3 mV/V and 2 mV/V load cell
A 3 mV/V cell produces a higher full-scale signal at the same excitation voltage. This alone does not mean it is more accurate. Accuracy is assessed together with combined error, temperature effect, creep, repeatability, and the electronic measurement chain.
Why is nominal output tolerance important?
The datasheet may contain a statement such as 2.0 ±0.002 mV/V. In multi-cell systems, close nominal outputs of the cells make corner balancing easier. Still, the junction box, cable length, and mechanical load distribution may require separate adjustment.
Compatibility with indicator input range
The calculated maximum mV signal should not exceed the indicator’s input range, and the minimum load change should remain above the device’s noise and resolution limit. Merely looking at the display divisions is not sufficient; the input sensitivity, internal resolution, filtering, and stable counts should be examined.
Does the signal increase when multiple load cells are connected?
In cells of the same type connected in parallel and sharing the load, the system’s mV/V ratio usually remains the same as with a single cell. Capacity and load distribution change; the signal is not simply multiplied by the number of cells. The minimum total bridge resistance that the indicator can supply should also be checked.
Difference between zero balance and mV/V
Zero balance is the initial signal that occurs without applying a load and can be given as a percentage of the nominal output. mV/V is the sensitivity at full load. A large zero deviation may indicate mechanical preload, mounting stress, temperature, or damage.
Why use a transmitter?
Millivolt level is prone to noise over long distances. Load cell transmitter, this signal can be converted to 4–20 mA, 0–10 V, or digital communication format. Before conversion, the input range and excitation voltage must be compatible with the cell.
Frequently Asked Questions
Does the mV/V value indicate capacity?
No. Capacity represents the mechanical load limit, while mV/V indicates electrical sensitivity.
Does accuracy increase if the excitation voltage is raised?
The signal amplitude increases, but the manufacturer’s maximum voltage must not be exceeded. Heating and electronic limits may negatively affect accuracy.
Can mV/V be measured with a multimeter?
Millivolt measurement can be carried out with an appropriate resolution; for reliable characterization, a stable power supply, reference load, and calibrated measurement system are required.
When selecting a product, examine sensitivity, accuracy class, and environmental protection along with capacity. You can compare Kobastar load cell options or request technical support.