Check calibration sheet for correct resistances. If these are more than 3 kΩ, then it is bad load cell and most likely due to electrical surges or lightening. See diagram below for testing resistances. Check resistance of strain gauges one by one. Weigh cells convert force to electrical signals for precise weight measurement in applications like industrial weighing, production and port.A different of more than 0.1 Ω signifies a bad load cell. Check input and output resistance with a multi-meter (resistance accuracy of 0.025 Ω or better) to make sure it is within the allowed tolerance of the product.Ideally the insulation resistance should be more than 5 Giga Ω. If the resistance is below 2 Giga Ω, then the insulation is bad. Use a multi-meter to check insulation of wire leads to the metal body of the load cell. Remove the load and check if the mV/V output returns to the allowed tolerance. Load the load cell between 50% to 100% of its capacity for 5 seconds. Make sure it is within the allowed tolerance. Connect the load cell to a stable power supply and measure the mV/V output like the step before. Refer to the calibration certificate of the load cell to see if this mV/V value is within the tolerance of load cell specification. With a multi-meter measure the output voltage in mV and divide it by the input voltage in V to get mV/V. Connect the input to a stable, low noise power supply. Position the load cell with no load attached. Even a very small deflection can have adverse effect on the load cell. Make sure there is no bending and bucking marks on the load cell. Use a straightedge and flashlight technique for correct visual inspection. Do visual check for flatness (for single point and double ended load cells).Load cell contain sensitive components and any shocks caused by dropping or being hit can damage the electronics inside. Check load cell element for any dents, deformation, cracks, rippling of metal, corrosion, and significant wear in the area of loading. Any cuts, crimps, excessive aberration or exposed wires is a sign of damage.
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