Reliable low-power domotic module designed to enable/disable loads saving energy consumption, zeroing the standby power.

It uses 3 latching relays, 15A 250Vac, that does not consume anything when are active, and can be used to enable loads or generators up to 3kW that are OFF for long time. Also, removing power to loads during lightning storms helps prevent damage from electrostatic discharges.

It also have 1 AC input to sense 230Vac voltage (detecting power outage), that acts also as a zero-crossing detector that permits to enable relays when voltage is zero (to minimize in-rush current, in case of capacitive loads) and disable relays when current in zero (to minimize overvoltage in case of inductive loads).

4 low voltage inputs, that can be configured as analog or digital, permit to connect pushbutton switches, NTC thermal probes, alarm sensors and energy / gas / water meters with pulsed output.

The 3 latching relays can be used to enable/disable:

• heat pump, that normally consumes more than 5W in standby
• boiler, heater or other appliances consuming power in standby
• gate and garage door, that normally consumes more than 5W/each in standby, and it's also good to disable them when away alarm is active to prevent thefts.
• small photovoltaic systems, less than 3kWp
• outdoor lights

Features

• 3x 15A SPST latching relays, that permit to manage up to 3kW loads or generators 230Vac
• 1x AC input, 100-250V, that is used for two functions: zero-crossing detector + voltage presence
• 4x configurable low voltage inputs, analog or digital: each input, using GND as common voltage, can be configured as pushbutton, twinbutton (UP/DOWN buttons that uses a single input), alarm sensor (magnetic, PIR, ...), NTC 10k thermal sensor, counter / meter with pulsed output.
• only 15mW power consumption, even if one or more relays are ON.
• available with two firmwares:
  • DomBus firmware, supporting the proprietary DomBus protocol, working with Domoticz
  • Modbus firmware, supporting the standard Modbus RTU protocol, working with Home Assistant, OpenHAB, NodeRED, ...
• RS485 bus connection, industrial grade, 115200bps, permitting to use up to 500m of standard alarm cable (2x0.5mm² + 2x0.22mm² + shield) for connections.
• Very compact size: 59x42x21mm, fits everywhere, expecially in switchboxes and wallboxes.

Complete info at https://www.creasol.it/DomBus21 (the English page is the most up-to-date).