Sensor PZEM004T - brusdev/espurna GitHub Wiki
PZEM004T Energy Monitor
| Property | Value |
|---|---|
| Manufacturer | PEACEFAIR |
| Product page | AliExpress |
| Wiki page | ESPurna Wiki |
| Build flag | PZEM004T_SUPPORT |
Introduction
These are cheap Energy monitors devices, equipped with a TTL UART communication interface, it can monitor Voltage, Current, Power, and Energy.
NB.: These devices are 5V, usually, ESP devices are using ESP8266 which is 5V tolerant [1], Sonoff Basic devices have 5V onboard, so you don't need to mod your PZEM004T to work with ESP8266 devices.
Sensor Behaviour
Differently than the first implementation(See commit 3704d366637), this version(See PR #1304) pools
device(s) magnitudes every PZEM004T_READ_INTERVAL. A magnitude of a device is read on each sensor tick.
This will offload the main thread, as the PZEM004T can take up to 1000ms to answer the request. Same
magnitudes are read one after another, so they can be better synced.
Basic Configuration (Single device)
You only need to connect 4 pins to ESPurna device to work:
- VCC
- TX
- RX
- GND
ESPurna's GPIO vary among devices, check the documentation of your device.
You must enable the build flag PZEM004T_SUPPORT to enable this sensor.
Nothing is needed to be done in this single configuration, the device address will be set to the device on power on, works out of the box.
Advanced Configuration (Multiple devices)
Each PZEM004T device has an internal device address(Coded in the form of an IP Address but doesn't need to conform, you can have 0.0.0.0 for example), which can be used to create a pseudo-master/slave bus, allowing to connect multiple devices to the same UART, thereby eliminating software serials, etc.
ESPurna firmware has all the instrumentation to build this kind of bus.
Connection
To create a master/slave UART bus, you need a resistor(10K) and some Small Signal Schottky Diode(Like BAT43), the connection diagram is the following:
Configuration
You need to specify in config/sensors.h the addresses of the devices:
#define PZEM004T_ADDRESSES "1.1.1.1 2.2.2.2 3.3.3.3"
Also, you need to configure these addresses in the devices itself, see PZ.ADDRESS command below.
Commands
PZEM004T sensor implementation provides 3 commands to manage the device(s). When specified ADDRESS,
it is the address set on the device, like 192.168.1.1, 1.1.1.1, etc. When specified DEVICE_INDEX,
is the internal's device index, the order is defined by the addresses in the PZEM004T_ADDRESSES build
flag. The command's output is: Device DEVICE_INDEX/ADDRESS.
PZ.ADDRESS
Allows you to read and to set the address.
Usage: pz.address [ADDRESS]
If ADDRESS is not provided, it will read the addresses of the devices configured in the firmware, eg:
$ pz.address
[7325151] [SENSOR] PZEM004T
[7325153] Device 0/192.168.1.1
[7325155] Device 1/192.168.1.2
[7325157] Device 2/192.168.1.3
[7325159] +OK
If ADDRESS is provided, it will issue a set address command to the bus. If the command doesn't return
a +OK the command has failed.
$ pz.address 192.168.1.1
+OK
NB.: Keep in mind that you must have ONLY ONE device connected to the bus when issuing this command, otherwise, all devices will have the same address and a collision will occur on the response, the result is undetermined.
PZ.RESET
Allows you to reset the accumulated energy value. Will read current energy value and store as the initial value, thus, the next reading will be 0(zero).
Usage: pz.reset [DEVICE_INDEX]
if DEVICE_INDEX is not provided, will reset all devices, eg:
$ pz.address
[7325151] [SENSOR] PZEM004T
[7325153] Device 0/192.168.1.1 - Offset: 3.4142
[7325155] Device 1/192.168.1.2 - Offset: 1.2344
[7325157] Device 2/192.168.1.3 - Offset: 7.4523
[7325159] +OK
if DEVICE_INDEX is provided, will reset only the provided device, eg:
$ pz.address 1
[7325151] [SENSOR] PZEM004T
[7325155] Device 1/192.168.1.2 - Offset: 1.2344
[7325159] +OK
PZ.VALUE
Allows you to read the last reading, not necessarily the
Usage: pz.reset [DEVICE_INDEX]
$ pz.address
[7325151] [SENSOR] PZEM004T
[7325155] Device 0/192.168.1.1 - Current: 1.1254 Voltage: 128 Power: 144 Energy: 3.4142
[7325155] Device 1/192.168.1.2 - Current: 3.2114 Voltage: 128 Power: 412 Energy: 1.2344
[7325155] Device 2/192.168.1.3 - Current: 6.2547 Voltage: 128 Power: 801 Energy: 7.4523
[7325159] +OK