Manual Patched | Peacefair Pzem051

There is typically one main button (or touch area) on the front.

To Reset Energy (kWh):

To Set the Power Alarm (if supported/enabled): This is where the "patched" version shines. peacefair pzem051 manual patched

The original manual provides an incomplete Modbus register table. Worse, some registers are swapped (e.g., Voltage and Current addresses are incorrectly labeled). Below is the patched, verified register map for firmware version 2.1+ (most common as of 2024).

| Parameter | Register Address (Hex) | Function Code | Data Type | Scaling Factor | Patched Correction | | :--- | :--- | :--- | :--- | :--- | :--- | | Voltage | 0x0000 | 0x04 | Unsigned short | 0.1 V | Correct | | Current | 0x0001 | 0x04 | Unsigned short | 0.01 A | Correct | | Power | 0x0002 | 0x04 | Unsigned short | 0.1 W | Was incorrectly listed as 0x0003 | | Energy (High Word) | 0x0004 | 0x04 | Unsigned long | 1 Wh | Original manual swapped high/low | | Energy (Low Word) | 0x0005 | 0x04 | Unsigned long | 1 Wh | Original manual swapped high/low | | Device Address | 0x07D0 | 0x03/0x06 | Unsigned char | 1 | Original listed as read-only; it is writable | There is typically one main button (or touch

Patched Modbus Example Request: To read voltage (address 0x01): Send: 01 04 00 00 00 01 31 CA

Common patched fix: If you get no response, change your serial settings to 9600 baud, 8 data bits, no parity, 1 stop bit (8N1). The original manual incorrectly implies auto-baud detection. To Set the Power Alarm (if supported/enabled): This

Original manual's advice: "Check baud rate."

Patched solution: The PZEM-051 clears current readings when the load is disconnected. This is normal. However, there is a firmware bug where the current register holds the last value for 2 seconds after disconnection, then jumps to 0. To patch this in software: implement a moving average filter in your Modbus master.