SDM-SW8A 8 Channel Switch Closure Input Module

The SDM-SW8A is an 8-channel pulse count module

Each channel can be individually configured for single-pole double throw (SPDT), single-pole single throw (SPST), or voltage pulse measurements. Output options include state, duty cycle, or counts. The SW8A is well suited for use in energy mangement studies. We recommend a maximum of four SW8As be connected to a single datalogger.



  • Provides eight individually configured channels
  • Measures reed switches, dry contacts, or slow voltage pulses
  • Supports single-pole double-throw (SPDT), single-pole single-throw (SPST), or voltage pulse measurements
  • Conforms to EN55022-1:1995 and EN50082-1:1992



  • Operating voltage: 9.6 to 16 V
  • Typical current drain: 3 mA quiescent, 6 mA active (max)
  • Input voltage threshold: from below 0.9 to above 4.0 Vdc; ±20 Vdc max
  • Maximum input frequency: 100 Hz (50% duty cycle)
  • Minimum input pulse width: 5 ms high, 5 ms low
  • Maximum bounce time: 3 ms open without counting
  • Operating temperature range: -25° to +55°C

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