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SART technology

in 868 MHz radio modules


SART technology extends relay lifetime


Contacts last longer with SART. To allow radio modules with miniaturised relays to be operated safely, reliably and for a long time at high switching loads (230 V, 16 A), they come with optional SART technology (Smart Adaptive Relay Triggering).

The main purpose of SART technology is for switching relay contacts on and off at zero current. With ohmic loads this is very simple, because the voltage zero crossing is usually available for activation. With phase-shifted loads, however, it may be highly counterproductive because long, high-energy arcs may be produced that may seriously damage the relay contacts or make the relay and therefore the whole product unusable.

The SART technology comprises the following core functionalities

  • Continuous microcontroller-based high-frequency recording of current, voltage and phasing
  • Relays activated in load-free voltage zero crossing
  • Continuous correction of switching point in relation to pick-up and drop-out times of relays over lifetime
  • (operating time increases with contact erosion)
  • Relays deactivated in load-free current zero crossing
  • Detection & differentiation of out-of-phase but permanently sinusoidal currents and
  • pulse-like loads, as in switching power supplies and leading-edge controllers (e.g. in dimmers)
  • Detection and use of 'low-current windows' for relay activations for irregular current profiles

The advantages at a glance


  • Long-life relay contacts / radio modules
  • High product availability
  • 500 000 or more switching cycles possible at full load
  • Module size same as standard radio modules
  • Compatible with almost all Bachmann products

Relay contacts without SART


Relay contacts without SART technology on mockup of PC mains adapter, defective / burned out after less than 500 switching cycles (random switching point) with clearly seen arc on oscillogram of current profile

Relay contacts with SART


Relay contacts with SART technology on mockup of PC mains adapter, after far in excess of 12 000 switching cycles (microcontroller-controlled switching point) with oscillogram

Key facts


  • 868 MHz ISM band
  • Radio range min. 50m outdoors
  • Relay switching capacity 16A at 230VAC
  • Remote control with 3 switching groups ON/OFF
  • Switching groups with two flexibly assignable radio modules
  • Small module size
  • High-quality electronics
  • Good penetration
  • SART technology for long product availability