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

4.2.1 Current Transformer Results

For the following test results, gain and phase calibration are applied to the EVM using CR8350-2500-N current transformers from CR Magnetics Inc. In the following results, the active energy results are within 0.1% at 0° phase shift. Additionally, the active energy versus voltage results and the RMS voltage results show that good accuracy results are able to be obtained despite using only a fraction of the ADC range for the voltage channels.

The % Error columns in the following tables and plots are calculated as the difference between the multiple reference input values to ADS131M08MET-EVM and the measured values, shown on the PC GUI. The reference input values to ADS131M08MET-EVM are generated by a PTS3.3C source generator meter or reference meter from MTE, while the measured values calculated by the Energy Library are reported in the PC GUI.

Table 4-1 CT-Based RMS Voltage % Error Versus Voltage, 3-Phase Mode
VOLTAGE (V)% ERROR Phase A% ERROR Phase B% ERROR Phase C
2700.005550.014440.02444
2600.003840.013070.02461
2400.003750.005000.0112
2300.010860.003040.01652
2200.008630.010900.00090
2000.007000.005000.00650
1800.010550.001110.00388
1600.002500.006870.01874
1400.002140.004280.00071
1200.006660.019160.00999
1000.003000.009000.00200
900.013000.009220.00988
ADS131M08MET CT-Based RMS Voltage % Error Versus Voltage, 3-Phase ModeFigure 4-4 CT-Based RMS Voltage % Error Versus Voltage, 3-Phase Mode
Table 4-2 RMS Current % Error Versus Current, 3-Phase Mode
CURRENT (A)% ERROR Phase A% ERROR Phase B% ERROR Phase C
0.10.003990.044980.00499
0.250.022390.011590.00200
0.500.001790.012200.01940
1.000.019990.014990.00500
2.000.016490.004490.00699
5.000.005390.013390.01139
10.000.009990.010000.00950
20.000.014490.014490.02570
30.000.033660.026660.02899
40.000.011240.028250.03625
50.000.013980.010190.01720
60.000.015660.016830.01166
70.000.006420.004140.01842
80.000.007490.004750.01062
90.000.023210.019880.00100
100.000.020990.031990.00120
ADS131M08MET RMS Current % Error Versus Current, 3-Phase ModeFigure 4-5 RMS Current % Error Versus Current, 3-Phase Mode
Table 4-3 Active Energy % Error Versus Current, 3 CTs With a Turns Ratio of 2500:1 Each
CURRENT (A)AVG ERROR (%)
PF = 1, cos ϕ = 0°		LIMIT (%)
[CLASS 0.1]
IEC 62053-22
(PF 1)		LIMIT (%)
[CLASS 0.2]
IEC 62053-22
(PF 1)		AVG ERROR (%)
PF = 0.5i,
cos ϕ = 60°		LIMIT (%)
[CLASS 0.1]
IEC 62053-22
(PF 0.5i|0.8c)		LIMIT (%)
[CLASS 0.2]
IEC 62053-22
(PF 0.5i|0.8c)		AVG ERROR (%)
PF = 0.8c
cos ϕ = –36.87°
1.00.024±0.2±0.4
1.50.013±0.1±0.2
30.001±0.1±0.20.0930.250.5-0.084
100.009±0.1±0.2
150.005±0.05±0.10.0400.150.3-0.055
300.009±0.1±0.2
500.008±0.1±0.2–0.0870.150.3-0.015
750.027±0.1±0.2
900.047±0.1±0.2
1000.014±0.1±0.2–0.1220.150.30.061
ADS131M08MET Active Energy % ErrorFigure 4-6 Active Energy % Error
Table 4-4 Starting Load Test, cos ϕ = 1i (0°) 0.5A
VOLTAGE (V)AVERAGE ERROR (%)Test
Current (A)
90–2.0620.05
Table 4-5 Variation of Voltage, cos ϕ = 1i (0°)
VOLTAGE (V) TEST
CURRENT (A)		 AVERAGE
ERROR (%)		 LIMIT (%)
[CLASS 0.1]		 LIMIT (%)
[CLASS 0.2]
120 1.5 0.075 REF REF
108 1.5 0.072 ±0.1 ±0.2
235 1.5 0.074 ±0.1 ±0.2
270 1.5 0.071 ±0.1 ±0.2
297 1.5 0.069 ±0.1 ±0.2
120 15 0.053 REF REF
108 15 0.053 ±0.1 ±0.2
235 15 0.055 ±0.1 ±0.2
270 15 0.052 ±0.1 ±0.2
297 15 0.052 ±0.1 ±0.2
Table 4-6 Phase Sequence Reversal
CIRCUITTEST
CURRENT (A)		AVERAGE
ERROR (%)		LIMIT (%)
[CLASS 0.1]		LIMIT (%)
[CLASS 0.2]
ABC1.50.048REFREF
CBA1.50.041±0.1±0.3
ABC150.026REFREF
CBA150.018±0.1±0.3
Table 4-7 Equality of Current Circuits
CIRCUIT TEST
CURRENT (A)		 AVERAGE
ERROR (%)		 LIMIT(%)
[CLASS 0.1]		 LIMIT (%)
[CLASS 0.2]
All 1.5 0.056 REF REF
Circuit A 1.5 0.034 ±0.15 ±0.3
Circuit B 1.5 0.066 ±0.15 ±0.3
Circuit C 1.5 0.042 ±0.15 ±0.3
All 15 0.032 REF REF
Circuit A 15 0.011 ±0.15 ±0.3
Circuit B 15 0.046 ±0.15 ±0.3
Circuit C 15 0.030 ±0.15 ±0.3