A novel microreactor system for gas-phase catalyzed reactions is described for which the process components consist of modular circuitlike boards that fit the slots of a commercial computer chassis. The reactor board contains two parallel reactor channels on a single multilaminate silicon chip with independent controls for the gas flow rate and the reaction temperature. All fluidic interfaces between the various boards are performed using standard metal tubing and fittings. System automation was performed using a process logic controller with a human-machine interface for display of sensors and monitoring of process control loops. It was found that the control loop could successfully operate at 500 Hz with all 24 microreactor heaters being under closed-loop PID control.