Issue
Are the PM5000's registers saved as most significant or least significant register?
Product Line
PM5000 series meters (PM5100, PM5300, PM5500)
Environment
Modbus register reading program
Cause
When reading Modbus registers for a PM5000-series meter, the Modbus register read program may require that the data type be specified as Most or Least Significant Register for 32-bit or 64-bit registers.
For 16-bit registers, this may change to Most Significant or Least Significant Bit. The customer may also ask if the registers are big endian or little endian.
Resolution
PM5000 meters store data in the Most Significant Register format (Big Endian).
This means that the largest number gets stored in the smallest address.
Example:
Say that a number (123,456,789) is stored across three addresses (101, 102, 103).
If this data is stored as big endian (most significant bit/register), the largest number will get stored in the smallest address.
Big Endian (Most Significant Bit/Register)
| Address | Value |
| 101 | 123 |
| 102 | 456 |
| 103 | 789 |
If this data as stored as little endian (least significant bit/register), the largest number will get stored in the largest address.
Little Endian (Least Significant Bit/Register)
| Address | Value |
| 101 | 789 |
| 102 | 456 |
| 103 | 123 |
發佈於: 施耐德電機Taiwan
