The present invention provides a system and method for the detection of plasma excursions, such as arcs, micro-arcs, or other plasma instability, during plasma processing by directly monitoring direct current (DC) bias voltage on an RF power electrode of a plasma processing chamber. The monitored DC bias voltage is then passed through a succession of analog filters and amplifiers to provide a plasma excursion signal. The plasma excursion signal is compared to a preset value, and at points where the plasma excursion signal exceeds the preset value, an alarm signal is generated. The alarm signal is then fed back into a system controller so that an operator can be alerted and/or the processing system can be shut down. In certain embodiments, multiple processing regions can be monitored by a single detection control unit.