Device and method for controlling the pressure in an inflatable cuff of a blood pressure manometer
First Claim
1. A method for controlling the pressure in at least one inflatable cuff of a blood pressure measuring apparatus in closed-loop operation, where the pressure on the cuff equals the arterial pressure, with a plethysmographic sensor device, whereby a plethysmographic signal PG and a cuff pressure signal BP are obtained, comprising the following steps:
- a) in a first concentric inner control loop the cuff pressure signal BP is used as control variable and is fed into a difference amplifier as a first input signal,b) in a second concentric outer control loop, which is simultaneously active with the first concentric inner control loop for closed-loop operation, the plethysmographic signal PG, with its mean value PG
suppressed, is fed into a controller and is added to a set-point signal SP, and a target signal SW is generated, which is fed into said difference amplifier as a second input signal,c) an output signal AS of the difference amplifier is used to control at least one valve connected to a pressure source, which in turn regulates the pressure in the cuff, andd) no re-adjustments of set-point signal SP during open-loop operation with the help of a state-switch and timing-circuits.
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Accused Products
Abstract
The invention relates to a method and a device for regulating the pressure in at least one inflatable cuff, preferably a finger cuff (6), of a blood pressure manometer comprising a plethysmographic sensor device (8, 9) for detecting a plethysmographic signal PG and a pressure sensor (7) for detecting a cuff pressure signal BP. According to the invention, two control loops (1, 2) acting on a differential amplifier (10) are used to independently regulate different operating parameters, the first, inner control loop (1) using the cuff pressure signal BP as the first regulating variable, and the second, outer control loop (2) comprising a regulating device (12), preferably a PID regulator, which generates a nominal value SW as a second regulating variable from the plethysmographic signal PG. The differential amplifier (10) is connected, on the output side, to at least one valve connected to a pressure source (4), preferably a proportional valve (3; 25, 27), for regulating the pressure in the cuff (6). Additional outer control loops (16 to 21) can be used to respectively set a parameter of the device to a determined nominal value.
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Citations
18 Claims
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1. A method for controlling the pressure in at least one inflatable cuff of a blood pressure measuring apparatus in closed-loop operation, where the pressure on the cuff equals the arterial pressure, with a plethysmographic sensor device, whereby a plethysmographic signal PG and a cuff pressure signal BP are obtained, comprising the following steps:
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a) in a first concentric inner control loop the cuff pressure signal BP is used as control variable and is fed into a difference amplifier as a first input signal, b) in a second concentric outer control loop, which is simultaneously active with the first concentric inner control loop for closed-loop operation, the plethysmographic signal PG, with its mean value PG
suppressed, is fed into a controller and is added to a set-point signal SP, and a target signal SW is generated, which is fed into said difference amplifier as a second input signal,c) an output signal AS of the difference amplifier is used to control at least one valve connected to a pressure source, which in turn regulates the pressure in the cuff, and d) no re-adjustments of set-point signal SP during open-loop operation with the help of a state-switch and timing-circuits. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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- 8. A device for controlling the pressure in at least one inflatable cuff of a blood pressure measuring apparatus in closed-loop operation, where the pressure in the cuff equals the arterial pressure, comprising a plethysmographic sensor device for obtaining a plethysmographic signal PG and a pressure sensor for obtaining a cuff pressure signal BP, including two concentric control loops, which are simultaneously active during closed-loop operation, acting on a difference amplifier, the first concentric inner control loop uses the cuff pressure signal BP as a first control variable and the second concentric outer control loop includes a controller which generates a target variable SW from the plethysmographic signal PG as a second control variable, and wherein the output of the difference amplifier controls at least one valve connected to a pressure source, thereby regulating the pressure in the cuff.
Specification