SBOA575 September   2023 INA823 , OPA2387 , XTR115 , XTR116

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Theory of Operation
    1. 2.1 Wheatstone Bridge Sensor
    2. 2.2 2-Amp INA
    3. 2.3 4-20-mA Current Loop Transmitter Interface
  6. 3Simulation
  7. 4PCB Design
  8. 5Verification and Measured Performance
  9. 6Summary
  10. 7Reference
  11.   Appendix

5 Verification and Measured Performance

The measured output current versus weight is shown in Figure 5-1. The measured results are compared with the simulated and calculated values in Table 5-2. The measured results are ±0.1% accurate as shown in Figure 5-2. The experimentation setup with the load cell is detailed in the Appendix 1: Load Cell and Experimentation Setup. The total current consumption is calculated in Equation 14.

Equation 14. ITOTAL=IBRIDGE+I2AMP INA+IINA REF+IXTR=2mA+1.14mA+0.05mA+0.2mA→ITOTAL=3.39mA
Table 5-1 Design Goal vs Calculated, Simulated, and Measured Performance
WeightGoalCalculatedSimulatedMeasured
Iout (Min)0 lbs4 mA4.0959 mA4.0963 mA4.0994 mA
Iout (Max)20 lbs20 mA20.1404 mA20.1397 mA20.1545 mA
GUID-20230802-SS0I-RWGB-2VH7-D0RXMX0QZC91-low.svg Figure 5-1 Measured Output Current vs Weight Transfer Function
GUID-20230918-SS0I-1VZN-HBGQ-CNVW83GCSVJJ-low.png Figure 5-2 Output Current Error vs Weight