SBAU487 August   2025

 

  1.   1
  2.   Description
  3.   Getting Started and Next Steps
  4.   Features
  5.   Applications
  6.   6
  7. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Block Diagram
    4. 1.4 Device Information
  8. 2Hardware
    1. 2.1 Power Requirements
    2. 2.2 Header Information
    3. 2.3 Jumper Information
    4. 2.4 Slide Switches and Push Buttons
    5. 2.5 Test Points
    6. 2.6 Cautions and Warnings
    7. 2.7 Analog Inputs
      1. 2.7.1 Voltage Inputs
        1. 2.7.1.1 Voltage Measurement Analog Front End
      2. 2.7.2 Current Sensor Inputs
        1. 2.7.2.1 Current Measurement Analog Front End
          1. 2.7.2.1.1 Rogowski Coil Inputs
      3. 2.7.3 Analog Gain Setting
  9. 3Software Installation
    1. 3.1 GUI Operation
    2. 3.2 Launch the Metrology Software
  10. 4Energy Metrology Software Overview
    1. 4.1 Using the ADS131M08MET-EVM
      1. 4.1.1 Measuring Voltage and Current
        1. 4.1.1.1 Calibration Procedure
          1. 4.1.1.1.1 Gain Calibration
          2. 4.1.1.1.2 Voltage and Current Gain Calibration
          3. 4.1.1.1.3 Active Power Gain Calibration
          4. 4.1.1.1.4 Offset Calibration
          5. 4.1.1.1.5 Phase Calibration
    2. 4.2 Test Accuracy Results
      1. 4.2.1 Current Transformer Results
      2. 4.2.2 Rogowski Coil Results
    3. 4.3 Developing an Application
  11. 5Hardware Design Files
    1. 5.1 Schematics
    2. 5.2 Bill of Materials (BOM)
    3. 5.3 PCB Layouts
  12. 6Design and Documentation Support
    1. 6.1 Design Files
      1. 6.1.1 PCB Layout Recommendations
    2. 6.2 Tools and Software
    3. 6.3 Documentation Support
    4. 6.4 Support Resources
    5. 6.5 Trademarks

4.1.1 Measuring Voltage and Current

It is not necessary to apply AC Mains voltage to the EVM to evaluate the basic performance of the hardware and software. A dual-channel signal generator can safely be used to verify operation and get the basic metrology aspect of the EVM working. For example, the voltage inputs can be applied directly to test points 4, 5, and 6. With the shunt jumpers removed from JP1 through JP8, the voltage that is generated over the CT burden resistor can be applied directly to screw terminals J4, J8, J11, and J14.

With the voltage divider used on each of the three voltage input terminals, Mains voltage of 120V (as measured between the line and neutral) applied to J3, the voltage at TP5 is ±128mV (91mVRMS). For a mains voltage of 230V (as measured between the line and neutral), the 230V input to the front-end circuit produces a voltage swing of ±245.33mV (173.48mVRMS). The ±128mV and the ±245.33mV voltage ranges are both well within the ±1.2V input voltage that can be sensed by the ADS131M08 device for the default PGA gain value of 1 that is used for the voltage channels.

To verify the current channel inputs without using a current transformer or Rogowski coil, the second signal generator channel can be applied directly to J4 at the IAP and IAN terminals. Remove the shunts from JP1 and JP2 and inject a 60Hz sine wave of up to ±1V. The typical voltage found on the current channel inputs depends on the turns ratio of the CTs used or the sensitivity of the Rogowski coil. As an example, a current input of 100A and CT turns ratio of 2500:1, with the burden resistor of 12.98Ω used on this EVM, the input signal to the current channels has a voltage swing of ±918mV maximum (649mVRMS). Verify the current in the meter status panel. Figure 4-1 provides an example of using a low-voltage signal source to emulate 120VRMS and 10A inputs on Phase A.

ADS131M08MET Voltage and Current InputsFigure 4-1 Voltage and Current Inputs