6. Add Energy Sensing Node(s)

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The emonTx is an low power RF remote sensor node. Data is transmitted to an emonPi or an emonBase via a low power 433MHz radio.


Key Features

  • 4 x single-phase current sense (CT) channels
  • 1 x AC VRMS Channel
  • Supports multiple temperature sensors
  • Supports Optical Pulse Sensor
  • Can be powered single AC-AC adaptor (DC PSU not required)
  • Battery power option
  • RF Range is approximately similar to home WiFi (real world range depends on many factors e.g. thick stone walls)
  • Up to 2x emonTx can be connected to a single emonPi (up to 30x is possible with manual RF node ID setting*)
  • Approximate three-phase possible with firmware update
  • Wall-mount option

Note: it is possible to use emonTx ‘standalone’ (without emonPi / emonBase) with the addition of an ESP8266 WiFi module running EmonESP to post directly to Emoncms. See Using emonTx with the ESP8266 WiFi module

Setup emonTxView in Shop →


View in Shop →

Hardware Setup

1. DIP Switch Config

  • If more than one emonTx is to be used with the same base-station set the node ID using the on-board DIP switches*.
  • USA mode (enable 120V AC-AC adaptor calibration) can be toggled using DIP switches. See Wiki link above for further details

* More than 2x emonTx units can be connected to a single emonPi / emonBase with manual change of RF nodeID. This can be done This can be done via serial node ID config

2. Install Sensors

3. Power Up

  • Power emonTx directly from an AC-AC adapter (additional DC adapter not required)
  • Or alternatively power via 3 x AA batteries.
  • All sensors should be connected before power up

4. Indicator LED

  • Illuminates solid for a 10 seconds on first power up
  • Flash multiple times to indicate an AC-AC waveform has been detected (if powering via AC-AC adapter)
  • Flash once every 10s to indicate sampling and RF transmission interval

An emonTx can be powered by 3 x AA batteries; however, if possible, it is recommended to power the unit with an AC-AC adapter to provide an AC voltage reference for more accurate Real Power and VRMS calculations.

Base-station Emoncms Setup

The emonTx is compatible with emonPi / emonBase. RF transmission from the emonTx should be picked up automatically and data should appear in local Emonms Inputs page.

If Remote logging has been setup, data will also be posted to Emoncms.org.

1. Log inputs to feeds

Note: if using more than two emonTx units (with custom RF node ID or modified firmware) emonhub.conf node decoders will need to be setup.

Next step: Add Temperature Node(s) »