HDPM6000 Modbus Read registers 'System Firmware Version' and '3-Phase Meter Firmware Version' do not match Webpage Firmware Versions
Issue
When reading firmware version information from the HDPM6000 using Modbus registers, the values in the "System Firmware Version" and "3‑Phase Meter Firmware Version" registers do not match the firmware versions displayed on the device webpage. Only the deprecated System firmware version decimal register (Register 1) aligns with the webpage. This leads to confusion when validating firmware levels through third‑party Modbus tools such as ModScan or through a BMS/EMS.
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Product Line
HDPM6000, Branch Modules
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Resolution
The mismatch is expected behavior. The values in the following registers are encoded and not readable as direct decimal firmware versions:
Register 3: System firmware version
Register 4: 3‑phase meter firmware version
(Registers 4 and 5 when viewed in ModScan due to 1‑based offset)
The binary format of the polled registers is shown below, and the discrepancy occurs because the values are encoded and must be parsed using the method described in the following section:
The format is: Major.Minor.Patch version or first.middle.last -> For example, for 3 Phase Meter: 1.44.0 -> 1: Major version, 44: Minor version, 0: Patch version
4 MSBs are first number, next 8 bits are middle number, last 4 bits are last.
For 3 Phase Meter:
1.44.0 -> 0001,00101100,0000
For System Firmware:
64.2 -> 0000,01000000,0010
How to Decode the Modbus Register Values:
Encoding for registers 3 (System firmware version) and 4 (3-phase meter firmware version) which are Registers 4 and 5 in ModScan (1-based offset), isolate each version with logical AND, then shift:
To get 1st term: logical AND register with 0xF000. Then right shift 12 bits: Major = (Register AND 0xF000) >> 12
To get 2nd term: logical AND register with 0x0FF0. Then right shift 4 bits: Minor = (Register AND 0x0FF0) >> 4
To get 3rd term: logical AND with 0x000F (no shift): Patch = (Register AND 0x000F)