Abstract: A control system 10 for monitoring operation of a high pressure plunger pump 12 includes a microprocessor-based controller 40 and a plurality of sensors. Inlet pressure transducers 48 output electrical signals to the controller at intervals of less than 1 millisecond, indicative of the instantaneous inlet pressure to the pump. The controller 40 shuts down pump operation if a number of instantaneous pressure signals within a selected time period exceeds a predetermined value, or if the average inlet pressure signal exceeds a preselected value. The control system 10 is substantially tamperproof, and stored data indicative of tampering, pump startup, pump shutdown, and pump alarm conditions are recorded in a memory for subsequent retrieval and analysis. The serial interface 82 allows communication between the system operating computer 68 and a setup/processing computer 84, which may optionally be remote from the control system by use of a modem.