Hello Paul,
Attached a simple view of a consumption connexion of the PZEM004T power meter on 230Vac mains.
This arrangement is normaly dependant on the way you pass the current wire inside the 100A Current Transformer. This has nothing to do with AC measurement but the direction of the energy flow. The convention is that if you consume power the average product V x I is positive and if you generate power ( with solar cells and inverter for exemple) the sign of the exchange is negative. The PZEM004T version 3.00 with embedded communication MODBUS RTU is not able to change the polarity of the power when you invert the Current Transformer current flow!
There is no software supplied with it only the simplified protocol used to acces the registers. This part works fine after understanding how CRC control bytes are organized. ( probably HH and LL bytes inverted!)
The PIC and DSP embedded inside the Vango V9881D have a lot of registers and the documentation found in the china's manufacturer site is gigantic to read and not easy to understand.
If anybody has encounter such a difficulty to identify when the power is consummed or generated I am interested to know it to adapt my display software!
Regards, JF
