Power monitor

[Daniel Wee]

https://openenergymonitor.org/emon/buil ... ransformer

[Daniel Wee]

PZEM-004T power monitor module

https://www.banggood.com/PZEM-004T-TTL- ... rehouse=CN

Needs to be powered with 5V over the TTL UART port connector.

Note that the PZEM-004T-10A and the PZEM-004T-100A has different wiring configurations for the power and sensor inputs.

PZEM-004T-100A.jpg (45.81 KiB) Viewed 28947 times

The current transformer does not appear to be polarity sensitive although I'm not sure if this impacts the phase measurements.

[Daniel Wee]

Descriptions:

This is a mini split base current transformer; it's the smallest one compared to the similar products (output 100MA). Fully enclosed, good mechanical properties and environmental resistance, strong voltage isolation capability, safety and reliability. Used for energy meter in special; AC 220v, 380v power supply can both be applied.

Features:

This is a mini split base current transformer; it's the smallest one compared to the similar products (output 100MA).
The diameter of inner hole is 16mm, the accuracy is ≤0.5 grade,
Using snap joint structure, it can be fixed to the cable directly through nylon ties.
Built-in input coil; small and light, easy to install.
Fully enclosed, good mechanical properties and environmental resistance, strong voltage isolation capability, safety and reliability.
Specifications:

Brand: PEACEFAIR

Model: PZCT-02

Environment temperature: -40℃~+85℃
Relative humidity: ≤ 90%(40℃)
Working frequency: 50Hz~60Hz
Insulation endurance grade: B grade (130℃)
Insulation resistance: >1000MΩ normally
Dielectric strength: can afford power frequency 1000V/1minute
Flame resistance: Conform to UL94-Vo grade
Internal resistance: 10Ω
Measuring range: 0-100A

Weight:59g

[Daniel Wee]

The SCT013-000 split core current transformer handles 0-100A with a maximum output of 50mA whereas the PZCT-02 has a maximum output of 100mA. Basically, for the SCT013-000 - 100A=50mA while for the PZCT-02 - 100A=100mA. This means we will probably need to recalibrate, or use a more suitable CT.

The CT inputs of the PZEM-004T-100A measure 0.5ohms or less, which seems rather low. Assuming a 100mA input, the product voltage is 0.1A * 0.5ohms = 0.05V at full-scale. This does not seem to be correct.

20200921_165130[1].jpg (1.53 MiB) Viewed 28941 times

[Daniel Wee]

The main IC in the PZEM-004T is a "V9881D" energy measurement IC by Vango Tech.

The CT inputs go to the IBN (pin 4) and IBP (pin 5) which is actually shorted together, and possibly referencing Vss as the other leg. These are the Input-B positive and negative channels - so why are they shorted together?

20200921_170710[1].jpg (2.05 MiB) Viewed 28942 times

[Daniel Wee]

Programming commands can be found in attached PDF

[Daniel Wee]

This project is close to what we want.
https://primalcortex.wordpress.com/page/2/

It seems that the V3.0 board that I have uses the modbus protocol and not just the usual serial protocol.

https://www.arduino.cc/reference/en/lib ... s-esp8266/