The Altronic CPU-2000 is a 24 Vdc-powered, microprocessorbased digital ignition system for application to large natural gasfueled engines. Advanced control, diagnostic, display, communications, and emissions-reduction features allow for monitoring and control of the engine’s ignition and combustion. An optional Diagnostic Module, easily retrofit to existing CPU-2000 installations, enables users to monitor and act upon changes in spark voltage demand. Critical operating parameters and diagnostic messages are displayed on the Logic Module’s alphanumeric, backlit display. These include engine RPM, ignition timing angle, energy level, multistrike mode, and system and pickup faults. Most system features, including global and individual cylinder timing, ignition energy, multi-strike mode, and overspeed setpoint are accessible from the keypad as well as via an RS-485 serial port. Setup and application-specific adjustments are made through a standard personal computer. The optional Diagnostic Module uses innovative technology to indicate relative spark plug voltage and the need for spark plug replacement on an individual cylinder basis. The patented Altronic approach requires no external sensors or connections to the hightension leads. The system can automatically control system energy levels in relation to the monitored spark plug voltage requirement to provide higher energy levels only when needed, thus minimizing spark plug erosion. Existing Altronic II-CPU coils, pickups and cables, primary harnesses, and junction boxes are reused with the CPU-2000 system allowing for simple and economical retrofit.