The PZEM-004T together with a HW-655 Relay provide a good clamp-on energy monitor for a 240V clothes dryer.
Parts needed
- Circuit Box
- 3-prong Dryer Electrical Cord (Note - some households use a 4-prong plug)
- 3-prong Dryer Receptacle (Note - some households use a 4-prong plug)
- PZEM-004T
- HW-655 w/ ESP-01
- ESHION SPSD-5S AC-DC 5V Buck Converter
- 4-pin Serial Connector
- DuPont Connectors & 22 AWG wire
Preparation
Install TASMOTA (tasmota.bin) is sufficient) on the ESP-01 and confirm it is functional before connecting the PZEM-004T to its serial interface. Use of pins other that the default hardware serial GPIO (01 & 03) (requires 2.4.2 ESP Core or higher) in order for TASMOTA to emulate a serial interface using software serial.
Hardware connections
Connect the serial interface of the HW-655 with the serial interface of the PZEM-004T.
As most parts are connected to high voltage AC it is recommended to fit the hardware in a solid enclosure.
Software configuration
Device Template
PZEM-004T version prior to V3:
{"NAME":"HW-655 PZEM","GPIO":[0,63,0,62,0,0,0,0,0,0,0,0,0],"FLAG":0,"BASE":18}
PZEM-004T version V3:
{"NAME":"HW-655 PZEM","GPIO":[0,98,0,62,0,0,0,0,0,0,0,0,0],"FLAG":0,"BASE":18}
Use the module template to configure the GPIO's for hardware serial connection.
IMPORTANT: If using the connections as following, the communication works in all cores due to TASMOTA using hardware serial. If the user wants to use other GPIOs for communication, TASMOTA will emulate a serial interface using software serial. This feature does not work using core 2.3.0 due to insufficient RAM. To use the software serial feature, you must use a core version of 2.4.2 or greater.
Calibration
Per Theo - As the PZEM is a dedicated energy monitor, device calibration in TASMOTA is currently not supported.