The CellTrol II Bioreactor Control system may be configured with and without speed capability and in single or dual operating systems. The control system consists of an Allen Bradley Micrologix 1500 programmable Logic Controller (PLC) and an Allen Bradley HMI (Human-Machine Interface) Operator Interface. The control cabinet contains the PLC, HMI, probe signal conditioning transmitters, 115VAC control outlets and fixed rate pumps. Up to six customer-specified pump rates of 1rpm, 4 rpm or 10 rpm are available.The CellTrol II can be configured to accept a variety of analog probe signals from a cell culture vessel. Standard signals include pH, dissolved oxygen, temperature, weight, redox and tachometer feedback from the agitator. A digital input signal from a level probe can be used for antifoam addition for level control.