How to Use Load cell 50kg: Examples, Pinouts, and Specs

A load cell is a transducer that converts a force into an electrical signal. The 50kg load cell is specifically designed to measure weights up to 50 kilograms with high precision. It is commonly used in applications such as digital weighing scales, industrial automation systems, and force measurement devices. The load cell operates by detecting strain or deformation in its structure when a force is applied, and it outputs a small electrical signal proportional to the applied weight.

• Type: Strain gauge-based load cell
• Maximum Capacity: 50kg
• Rated Output: 1.0 ± 0.1 mV/V
• Excitation Voltage: 5V to 12V DC (recommended 10V)
• Input Resistance: 405 ± 10 ohms
• Output Resistance: 350 ± 3 ohms
• Non-linearity: ±0.03% of full scale
• Hysteresis: ±0.03% of full scale
• Operating Temperature Range: -10°C to +40°C
• Material: Aluminum alloy
• Dimensions: 34mm x 34mm x 8mm (approx.)
• Wiring: 4-wire configuration (Red, Black, White, Green)

The 50kg load cell typically uses a 4-wire configuration. Below is the wiring description:

1. Connect the Load Cell to an Amplifier:
   The output signal of the load cell is very small (in millivolts) and needs to be amplified. Use an HX711 load cell amplifier module for this purpose.

2. Wiring the Load Cell to HX711:

   • Connect the load cell wires to the HX711 module as follows:
     • Red wire to E+ (Excitation+)
     • Black wire to E- (Excitation-)
     • White wire to A+ (Signal+)
     • Green wire to A- (Signal-)
   • Connect the HX711 module to a microcontroller (e.g., Arduino UNO).

3. Calibrate the Load Cell:

   • Calibration is necessary to ensure accurate weight measurements. Use known weights to determine the calibration factor.

4. Write Code for the Microcontroller:
   Below is an example Arduino code to interface the load cell with an HX711 module:

   // Include the HX711 library
   #include "HX711.h"
   
   // Define pins for HX711 module
   #define DT 3  // Data pin connected to Arduino pin 3
   #define SCK 2 // Clock pin connected to Arduino pin 2
   
   // Create an HX711 object
   HX711 scale;
   
   void setup() {
     Serial.begin(9600); // Initialize serial communication
     scale.begin(DT, SCK); // Initialize HX711 with data and clock pins
     
     // Perform calibration (use known weights to find the calibration factor)
     Serial.println("Place a known weight on the load cell...");
     delay(5000); // Wait for user to place the weight
     scale.set_scale(); // Set the scale to default
     scale.tare(); // Reset the scale to 0
     Serial.println("Calibration complete.");
   }
   
   void loop() {
     // Read weight from the load cell
     float weight = scale.get_units(10); // Average 10 readings for stability
     Serial.print("Weight: ");
     Serial.print(weight);
     Serial.println(" kg");
     delay(1000); // Wait 1 second before the next reading
   }
   

• Mounting: Ensure the load cell is securely mounted to avoid mechanical vibrations or misalignment, which can affect accuracy.
• Overloading: Do not exceed the 50kg maximum capacity, as this can permanently damage the load cell.
• Temperature Effects: Use the load cell within the specified operating temperature range to maintain accuracy.
• Shielding: Use shielded cables to minimize electrical noise interference in the signal.

1. No Output Signal:

   • Cause: Incorrect wiring or loose connections.
   • Solution: Double-check the wiring and ensure all connections are secure.

2. Inconsistent Readings:

   • Cause: Mechanical vibrations or unstable mounting.
   • Solution: Ensure the load cell is mounted securely and the surface is stable.

3. Output Signal is Too Weak:

   • Cause: Insufficient excitation voltage or damaged load cell.
   • Solution: Verify the excitation voltage is within the recommended range (5V to 12V). Replace the load cell if damaged.

4. Calibration Issues:

   • Cause: Incorrect calibration factor or improper setup.
   • Solution: Recalibrate the load cell using known weights and ensure the HX711 module is functioning correctly.

Q1: Can I use the load cell without an amplifier?
A1: No, the output signal of the load cell is in millivolts and requires amplification. Use an HX711 or similar amplifier module.

Q2: How do I protect the load cell from environmental factors?
A2: Use a protective enclosure or coating to shield the load cell from moisture, dust, and extreme temperatures.

Q3: Can I use multiple load cells together?
A3: Yes, multiple load cells can be connected in parallel to measure larger weights, but ensure proper wiring and calibration.

Q4: What is the lifespan of a load cell?
A4: With proper usage and within specified limits, a load cell can last for many years. Avoid overloading and physical damage to extend its lifespan.