Flow Ctrl Tech Engineering

Oscilloscope Diagnostics for RS-485: Reflections, Ground Bounces & Slew Rate Distortion

Use a portable oscilloscope to diagnose mysterious serial communication failures: analyzing differential A-B waveforms, spotting missing termination ringing, and measuring common-mode offset.

  • A digital multimeter only measures time-averaged RMS voltage, missing microsecond reflection spikes entirely.
  • Connect Channel 1 to Line B, Channel 2 to Line A, and enable Math Channel (Ch1 - Ch2) with differential triggers.
  • High-frequency ringing at square wave edges confirms absent or improper 120-Ohm termination resistors.

Flow Ctrl Tech Engineering: Turnkey industrial automation, PLC programming, SCADA development, HMI, fieldbuses, and IIoT architectures. Contact our engineering center at [email protected] or phone +91 91110 91005.