Abstract: An alarm system for a computer-based monitoring system such as a patient medical monitoring system is provided. The system comprises a main processor connected to a first speaker, a second processor communicatively connected to the main processor for exchange of messages; and a second speaker controlled by the second processor. A sensor is communicatively connected to the main processor of the monitoring system for receiving input such as physiologic input from a patient. The second speaker acts as a back-up in the event that the main processor fails to annunciate an alarm or an operator fails to respond to the first alarm within a predetermined time interval. An audible alarm is sounded when the main processor or second processor are not functioning normally.

Abstract: A deflation control system for the pressurized cuff of an automatic blood pressure gauge uses a pressure sensor to control solenoid valves. The solenoid valves are responsive to respective pulse signals having variable duty cycles to change their time-apertures and, thus, their flow rates. The duty cycles of the pulse signals are controlled to maintain a desired constant rate of pressure reduction in the cuff. A microprocessor generates a control value which determines the duty cycles of the pulse signals. This value is proportional to the initial volume of fluid in the cuff and to a predictive term which is provided from a table that is indexed by cuff pressure. This value is then augmented by a feedback term, generated by a feedback control loop to ensure an accurate deflation rate. The gain of the feedback loop is selected so that the feedback correction signals do not interfere with pulse signals modulating the pressure signal. The feedback term is normalized by the initial volume measurement.