4-Wire Resistance Test and General Purpose Controller

4-Wire Resistance Test and General Purpose Controller

This microcontroller-based circuit board may be used as a complete stand-alone test controller. It is designed to safely perform a series of precision resistance tests while monitoring interlocks and other inputs and controlling door closures and air valves. Simple, easy to understand discrete logic is used, with extensive transient protection and noise reduction circuitry.

The Resistance Test board may be programmed to suit your requirements, whether as a precision resistance test system, or as a flexible, general purpose control board.

  • Precise current source with 1mA/10mA select
  • Instrumentation amplifier with gain select = 1/100
  • LCD driver built-in for 2×16 display with backlight
  • Motorola 68HC711E20 microcontroller
  • RS232 Interface
  • Output (250mA) for DC motor drive with reverse
  • Piezo speaker on-board
  • Internal reference resistance for test verification
  • Two 4-Wire inputs with selector
  • 11 general purpose sinking outputs
  • 3 general purpose logic inputs/outputs
  • Interlock and test start inputs
  • Interlock disconnects all resistance test outputs
  • 8 general purpose sinking inputs
  • Diagnostic LED indicators
  • Four position option switch
  • Fuse protection provided on all power supplies

Santa Barbara Automation delivers this board assembled, with schematics, calibration data and traceable certifications.

Downloads (PDF)