Shelly Pro EM

Shelly Pro EM is a single phase Energy Metering device with two channels of measurement and a relay (dry contact) output. The device measures consumed energy from the system and stores it on one minute intervals, with enhanced data for the Active Power, Apparent Power, Voltage, Current.

The following components are available in Shelly Pro EM:

• System
• WiFi
• Ethernet
• Bluetooth Low Energy
• Cloud
• MQTT
• Modbus
• Outbound Websocket
• 1 instance of Switch (switch:0)
• 2 instances of EM1 (em1:0, em1:1)
• 2 instances of EM1Data (em1data:0, em1data:1)
• Up to 10 instances of Script
• Virtual components
• BTHome components

Parameters

These parameters are used by the device to measure and report data to the user.

• voltage_limit_v - the voltage limit that the device can handle safely - set to 280V. Above 280V an error is triggered, the device will be damaged if higher voltages are applied.
• current_limit_a - the maximum current which the device can measure - set to 50A. The device is unable to measure above this limit, an error is triggered, the device will be damaged if higher currents are applied.
• power_threshold - the reporting threshold to notify for a change in Power value. Consists of two settings:
  • ratio - ratio between new value and last received value - set to 0.05 or 5%
  • absolute - absolute difference between new value and last received value - set to 10.0W
• voltage_threshold- the reporting threshold to notify for a change in Voltage value. Consists of two settings:
  • ratio - ratio between new value and last received value - set to 0.05 or 5%
  • absolute - absolute difference between new value and last received value - set to 1.0V
• current_threshold- the reporting threshold to notify for a change in Current value. Consists of two settings:
  • ratio - ratio between new value and last received value - set to 0.05 or 5%
  • absolute - absolute difference between new value and last received value - set to 0.01A
• energies are reported upon receiving a new value, they are not threshold dependent.

Device reports periodically on a predefined interval, regardless of the thresholds set above.

The switch:0 instance is not bonded to the power measurement, it can be controlled by the measured variables with the help of the local webhooks, or by a script.

Meter constant for the optical LED output Count of the device is set to 3600 ipm/kWh.

Useful Tools

A collection of tools for reading energy data off the device, reading momentary voltage, current, power values or monitoring and controlling the device from the command line can be found in this repository: https://github.com/ALLTERCO/shelly-cli-tools