TIDUF25A June   2023  – March 2025 ADS131M08 , MSPM0G1507

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 End Equipment
    2. 1.2 Electricity Meter
    3. 1.3 Power Quality Meter, Power Quality Analyzer
    4. 1.4 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 External Supply Voltage Supervisor (SVS) With TPS3840
      2. 2.2.2 Magnetic Tamper Detection With TMAG5273 Linear 3D Hall-Effect Sensor
      3. 2.2.3 Analog Inputs
        1. 2.2.3.1 Voltage Measurement Analog Front End
        2. 2.2.3.2 Current Measurement Analog Front End
    3. 2.3 Highlighted Products
      1. 2.3.1  ADS131M08
      2. 2.3.2  MSPM0G3507
      3. 2.3.3  MSP430FR4131 for Driving Segmented LCD Displays
      4. 2.3.4  TPS3840
      5. 2.3.5  THVD1400
      6. 2.3.6  ISO6731
      7. 2.3.7  ISO6720
      8. 2.3.8  TRS3232E
      9. 2.3.9  TPS709
      10. 2.3.10 TMAG5273
  9. 3System Design Theory
    1. 3.1  How to Implement Software for Metrology Testing
    2. 3.2  Clocking System
    3. 3.3  UART Setup for GUI Communication
    4. 3.4  Real-Time Clock (RTC)
    5. 3.5  LCD Controller in MSP430FR4131
    6. 3.6  Direct Memory Access (DMA)
    7. 3.7  ADC Setup
    8. 3.8  Foreground Process
      1. 3.8.1 Formulas
    9. 3.9  Background Process
    10. 3.10 Software Function per_sample_dsp()
      1. 3.10.1 Voltage and Current Signals
      2. 3.10.2 Frequency Measurement and Cycle Tracking
    11. 3.11 LED Pulse Generation
    12. 3.12 Phase Compensation
  10. 4Hardware, Software, Testing Requirements, and Test Results
    1. 4.1 Required Hardware and Software
      1. 4.1.1 Hardware
      2. 4.1.2 Cautions and Warnings
    2. 4.2 Test Setup
      1. 4.2.1  Connecting the TIDA-010243 to the Metering Test Equipment
      2. 4.2.2  Power Supply Options and Jumper Settings
      3. 4.2.3  Electricity Meter Metrology Accuracy Testing
      4. 4.2.4  Viewing Metrology Readings and Calibration
        1. 4.2.4.1 Viewing Results From LCD
        2. 4.2.4.2 Calibrating and Viewing Results From PC
      5. 4.2.5  Calibration and FLASH Settings for MSPM0+ MCU
      6. 4.2.6  Gain Calibration
      7. 4.2.7  Voltage and Current Gain Calibration
      8. 4.2.8  Active Power Gain Calibration
      9. 4.2.9  Offset Calibration
      10. 4.2.10 Phase Calibration
      11. 4.2.11 Software Code Example
    3. 4.3 Test Results
      1. 4.3.1 SVS Functionality Testing
      2. 4.3.2 Electricity Meter Metrology Accuracy Results
  11. 5Design and Documentation Support
    1. 5.1 Design Files
      1. 5.1.1 Schematics
      2. 5.1.2 BOM
      3. 5.1.3 PCB Layout Recommendations
      4. 5.1.4 Layout Prints
      5. 5.1.5 Gerber Files
    2. 5.2 Tools and Software
    3. 5.3 Documentation Support
    4. 5.4 Support Resources
    5. 5.5 Trademarks
  12. 6About the Author
  13. 7Revision History

4.3.2 Electricity Meter Metrology Accuracy Results

For the following test results, gain and phase calibration are applied to the meter. 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 6 tables and plots are calculated as the difference between the multiple reference input values to TIDA-010243 and the measured values, shown on the PC GUI. The reference input values to TIDA-010243 are generated by a PTS3.3C Source Generator/Reference Meter from the company MTE, while the measured values calculated by the TIDA-010243 Energy Library are reported in the PC GUI.

Table 4-3 Phase A RMS Voltage % Error Versus Voltage, 3-Phase Mode
VOLTAGE (V) % ERROR
270 0.00555
260 0.00384
240 0.00375
230 0.01086
220 0.00863
200 0.00700
180 0.01055
160 0.00250
140 0.00214
120 0.00666
100 0.00300
90 0.01300
70 0.01571
50 0.00240
30 0.01200
10 0.00299
9 0.02733
TIDA-010243 Phase A RMS Voltage % Error Versus Voltage, 3-Phase Mode Figure 4-11 Phase A RMS Voltage % Error Versus Voltage, 3-Phase Mode
Table 4-4 Phase A RMS Current % Error Versus Current, 3-Phase Mode
CURRENT (A) % ERROR

0.01

0.50383

0.03

0.20413
0.05

0.07749

0.1

0.00399

0.25

0.02239

0.50

0.00179

1.00

0.01999

2.00

0.01649

5.00

0.00539

10.00

0.00999

20.00

0.01449
30.00

0.03366

40.00

0.01124
50.00

0.01398
60.00

0.01566

70.00

0.00642
80.00

0.00749
90.00

0.02321

100.00

0.02099
TIDA-010243 Phase A RMS Current % Error Versus Current, 3-Phase Mode Figure 4-12 Phase A RMS Current % Error Versus Current, 3-Phase Mode
Table 4-5 Phase B RMS Voltage % Error Versus Voltage, 3-Phase Mode
VOLTAGE (V) % ERROR

270

0.01444

260

0.01307
240

0.00500

230

0.00304

220

0.01090

200

0.00500

180

0.00111

160

0.00687

140

0.00428
120

0.01916

100

0.00900

90

0.00922

70

0.02771
50

0.02240
30

0.02500
10

0.03400

9

0.02133
TIDA-010243 Phase B RMS Voltage % Error Versus Voltage, 3-Phase Mode Figure 4-13 Phase B RMS Voltage % Error Versus Voltage, 3-Phase Mode
Table 4-6 Phase B RMS Current % Error Versus Current, Three-Phase Mode
CURRENT (A) % ERROR

0.01

0.63311

0.03

0.26816
0.05

0.07893

0.10

 0.04498
0.25

0.01159
0.50 0.01220
1.00 0.01499
2.00

0.00449
5.00 0.01339
10.00

0.00100
20.00

0.01449
30.00 0.02666
40.00

0.02825
50.00

0.01019
60.00 0.01683
70.00 0.00414
80.00. 0.00475
90.00 0.01988
100.00 0.03199
TIDA-010243 Phase B RMS Current % Error Versus Current, 3-Phase Mode Figure 4-14 Phase B RMS Current % Error Versus Current, 3-Phase Mode
Table 4-7 Phase C RMS Voltage % Error Versus Voltage, 3-Phase Mode
VOLTAGE (V) % ERROR
9 0.02077
10 0.00699
30 0.00566
50 0.00960
70 0.00528
90 0.00988
100 0.00200
120 0.00999
140 0.00071
160 0.01874
180 0.00388
200 0.00650
220 0.00090
230 0.01652
240. 0.01124
260 0.02461
270 0.02444
TIDA-010243 Phase C RMS Voltage % Error Versus Voltage, 3-Phase Mode Figure 4-15 Phase C RMS Voltage % Error Versus Voltage, 3-Phase Mode
Table 4-8 Phase C RMS Current % Error Versus Current, Three-Phase Mode
CURRENT (A) % ERROR
0.01 0.32617

0.03

0.15916
0.05 0.09126

0.10

0.00499
0.25

0.00200
0.50

0.01940
1.00

0.00500
2.00

0.00699
5.00 0.01139
10.00 0.09506
20.00

0.05700
30.00

0.02899
40.00

0.03625
50.00

0.01720
60.00 0.01166
70.00

0.01842
80.00. 0.01062
90.00 0.00100
100.00 0.00120
TIDA-010243 Phase C RMS Current % Error Versus Current, 3-Phase Mode Figure 4-16 Phase C RMS Current % Error Versus Current, 3-Phase Mode
Table 4-9 Active Energy % Error Versus Current, Three CTs With a Turns Ratio of 2000:1 Each
CURRENT (A) AVG ERROR % PF = 1, cos ϕ = 0° LIMIT (%) [CLASS 0.2] IEC 62053-22 (PF 0.5i/0.8c) LIMIT (%) [CLASS 0.5] IEC 62053-22 (PF 0.5i/0.8c) AVG ERROR % PF = 0.5i, cos ϕ = 60° LIMIT (%) [CLASS 0.2] IEC 62053-22 (PF 0.5i/0.8c) LIMIT (%) [CLASS 0.5] IEC 62053-22 (PF 0.5i/0.8c) AVG ERROR % PF = 0.8c, cos ϕ = –36.87°
0,1 0,026 0,4 1,0 –0,002 0,5 1,0 0,038
0,5 0,021 0,4 1,0 –0,013 0,5 1,0 0,035
0,75 0,023 0,4 1,0 –0,004 0,5 1,0 0,037
1,5 0,017 0,2 0,5 –0,011 0,3 0,6 0,029
3 0,022 0,2 0,5 –0,012 0,3 0,6 0,036
7,5 0,019 0,2 0,5 –0,036 0,3 0,6 0,039
15 0,011 0,2 0,5 –0,045 0,3 0,6 0,032
30 0,009 0,2 0,5 –0,09 0,3 0,6 0,048
60 0,009 0,2 0,5 –0,158 0,3 0,6 0,072
75 0,016 0,2 0,5 –0,173 0,3 0,6 0,081
100 0,021 0,2 0,5 –0,202 0,3 0,6 0,097
TIDA-010243 Active Energy % Error Figure 4-17 Active Energy % Error
Table 4-10 Reactive Energy % Error Versus Current, Three CTs With a Turns Ratio of 2000:1 Each
CURRENT (A) AVG ERROR % sin ϕ = 1i (90°) LIMIT (%) [CLASS 1] LIMIT (%) [CLASS 0.5] AVG ERROR % sin ϕ = 0.5i (30°) LIMIT (%) [CLASS 1]

LIMIT (%) [CLASS 0.5]

 AVG ERROR % sin ϕ = 0.8c (– 53.13°)
0,1 0,193 0,410 –0,251
0,5 0,024

3,0

 2,0 0,079 –0,044
0,75 0,018 3,0 2,0 0,070 –0,032
1,5 0,006 2,0 1,0 0,047 3,0 2,0 –0,027
3 0,008 2,0 1,0 0,052 2,0 1,0 –0,017
7,5 0,003 2,0 1,0 0,071 2,0 1,0 –0,032
15 –0,006 2,0 1,0 0,023 2,0 1,0 –0,03
30 –0,002 2,0 1,0 0,095 2,0 1,0 –0,034
60 0,004 2,0 1,0 0,154 2,0 1,0 –0,052
75 0,015 2,0 1,0 0,187 2,0 1,0 –0,056
100 0.027 2,0 1,0 0,224 2,0 1,0 –0.042
TIDA-010243 Reactive Energy % Error Figure 4-18 Reactive Energy % Error