The present invention relates to a programmable control module that may be connected to existing instrumentation in order to automate manual operations and/or perform new sequences of functions. As one specific example, the present invention provides for a programmable control module that may be connected to a commercial cell washing machine, and which directs the automatic performance of steps required to enzymatically deantigenize erythrocytes. There are a number of advantages associated with the present invention. Valuable non-automated or semi-automated instruments may be rendered programmable by an add-on control module, thereby increasing the reproduciblity of function while reducing manpower requirements and avoiding the consequences of human error. Furthermore, the control module may be additionally connected to auxiliary devices which improve the function of the host instrument, including, for example, pumps, valves, or sensors (including safety monitoring devices).