Fluid status detector

• US 4,855,714 A
• Filed: 11/05/1987
• Issued: 08/08/1989
• Est. Priority Date: 11/05/1987
• Status: Expired due to Fees

• Current Assignee: Emerson Electric Company
• Original Assignee: Emhart Industries, Inc. (Stanley Black & Decker, Inc.)
• Inventors: MacIntyre, Steven A., Clarkson, Bruce A.
• Primary Examiner(s): Levy, Stewart J.
• Assistant Examiner(s): ROSKOS, JOSEPH
• Application Number:
  US07/116,788
• Time in Patent Office: 642 Days
• Field of Search: 340/521, 340/522, 340/605, 73/61.1 R, 73/49.2 T, 73/291
• US Class Current: 340/521
• CPC Class Codes: G01M 3/16 using electric detection means G01M3/045, G01M3/06, G01M3/12, G01M3/20, G01M3/24, G01M3/26 take precedence
• CPC Class Codes: G08B 19/00 Alarms responsive to two or more different undesired or abnormal conditions, e.g. burglary and fire, abnormal temperature and abnormal rate of flow

Abstract

There is a controller connected to a plurality of probes via a transmission line. Each probe includes sensors which provide voltage signals related to the fluid status in the probe environment. The voltage signals are applied to a voltage controlled oscillator which in turn provides an oscillating signal for transmission to the controller. A counter in the controller is controlled by a timer to count the number of oscillations of the transmitted signal over a predetermined time period. The count is represented by a digital signal which is processed to provide an indication of the fluid status of the probes. Probe circuit temperature is also transmitted to the controller for use in correcting the received oscillator frequency.

Claims

1. A fluid status detection system comprising:

a controller, a plurality of probes for sensing the status of fluids at probe locations remote from the controller, and a transmission line connecting said controller and said probes, wherein said controller comprises;

means for sensing the fluid environment of the probe and producing a voltage signal characteristic of the status of said fluid environment;

a voltage controlled oscillator means responsive to said voltage signal for providing an oscillating signal the frequency of which is representative of said status of said fluid environment; and

wherein said controller comprises indicator means responsive to said oscillating status signal for providing an indication of the sensed fluid status.

2. The fluid detector of claim 1 wherein said indicator means further comprises a means for varying the resolution of said sensed fluid status.

3. The fluid detector of claim 1 wherein said indicator means comprises:

timing means for determining a time period, and

counting means for counting the number of oscillations of said oscillating signal during said time period and for providing a digital signal representative of said number of oscillations.

4. The fluid status detection system of claim 1 wherein said voltage controlled oscillator means is incorporated in an electrical circuit and wherein said means for sensing further includes a means for sensing the temperature of said electrical circuit and for producing a voltage signal characteristic of said temperature.

5. The fluid status detection system of claim 1 wherein said means for sensing further includes a means for producing a reference voltage signal and for providing said reference signal to said voltage controlled oscillator for communication to said controller.