ANALOG SENSORS BUS

• US 20090138241A1
• Filed: 11/21/2008
• Published: 05/28/2009
• Est. Priority Date: 11/22/2007
• Status: Active Grant

• Current Assignee: Whirlpool Corporation
• Original Assignee: Whirlpool Corporation
• Inventors: GUTIERREZ, DIEGO NEFTALI, PARACHINI, DAVIDE
• Granted Patent: US 8,538,731 B2
• Time in Patent Office: Days
• US Class Current: 702/188
• CPC Class Codes: G01D 21/00 Measuring or testing not otherwise provided for
• CPC Class Codes: G01K 1/026 arrangements for monitoring a plurality of temperatures, e.g. by multiplexing
• CPC Class Codes: G01K 2207/06 for preparation purposes
• CPC Class Codes: G01K 7/20 in a specially-adapted circuit, e.g. bridge circuit
• CPC Class Codes: G08C 19/02 in which the signal transmitted is magnitude of current or voltage G08C19/36, G08C19/38 take precedence

Abstract

The present disclosure concerns an architecture for the connection and the communication of a plurality of passive sensors to a common control/measurement system, using an analog communication bus made of two physical wires only, and a method for reading the same sensors.

Claims

1. An apparatus for the acquisition of signals generated from a plurality of passive sensors (A, B, C, D, E, F, G, H, I, J, K, L, M, N, O), said passive sensors defining a non-linear circuit (NL, NL1, NL2, FNL1, FNL2) connected to a common measuring/control system (uC) through a physical wire connection, wherein the physical wire connection is made with only two wires (W1, W2).

2. The apparatus according to claim 1, wherein the passive sensors (A, B, C, D, E, F, G, H, I, J, K, L, M, N, O), contain analog devices only.

3. The apparatus according to claim 1, wherein the passive sensors are connected directly to the physical wires (W1, W2).

4. The apparatus according to claim 1, wherein that it also includes a generator (I1, I01, CC, OSC) for the selective activation of the passive sensors, the generator being preferably a small signal generator (I2).

5. The apparatus according to claim 1, wherein that it includes a passive sensor provided with junction diodes (D1, D2, D3, D4, D3A, D4A) and/or Zener diodes (DZ1, DZ2).

6. The apparatus according to claim 1, wherein that at least a passive sensor (J, K, L) is associated with a characteristic frequency (Fc0, Fc1, Fc2).

7. The apparatus according to claim 1, wherein that at least a passive sensor is a resonant circuit (M, N, O) associated to a resonant frequency (FR0, FR1, FR2).

8. The apparatus according to claim 1, wherein that passive sensors include resistive transducers (R1, R2, R3, R4, R5, RDT sensor 1, RDT sensor 2, RDT sensor 3, RTD sensor 0, RTD sensor 1, RTD sensor 2, RTD 0, RTD 1, RTD 2).

9. The apparatus according to claim 8, wherein that it is a meat probe suitable for measuring temperatures in different locations and adapted to be used in a domestic cooking oven.

10. The apparatus according to claim 4, wherein the generator is an oscillator (Osc) for the selective activation of the passive sensors (J, K, L, M, N, O).

11. A method for reading a plurality of passive sensors, connected to a common control/measurement system through a physical connection made with two wires, said passive sensors defining a nonlinear circuit, wherein the method comprises a step of selective activation of the passive sensor/sensors, a step of measurement of the electric parameters of the nonlinear circuit (NL, NL1, NL2, FNL1, FNL2), and a calculation step.

12. The method according to claim 11, wherein the step of selective activation is performed by supplying the non linear circuit with a voltage stepped signal or a voltage monotonic signal.

13. The method according to claim 12, wherein the electrical monotonic signal is generated by a reactive component (CC) during its charge and/or discharge transient.

14. The method according to claim 11, wherein the step of selective activation is performed applying a frequency signal to the nonlinear circuit, at least one of the frequency values FOsci (i=0 . . . n−

1) being preferably comprised in the flat portions (FL0, FL1, FL2) of the characteristic curve.

15. The method according to claim 14, wherein the frequency signal has a frequency equal or close to at least one of the resonant frequencies (FR0, FR1, FR2) of the nonlinear circuit or to at least one of the characteristic frequencies (Fc0, Fc1, Fc2) of the nonlinear circuit.

16. The method according to claim 11, wherein the step of measurement starts when a resonant frequency (FR0, FR1, FR2) of the nonlinear circuit is identified.

17. The method according to claim 11, wherein the step of measurement is in synchronism with the selective activation of the passive sensor/sensors.

18. The method according to claim 11, wherein the calculation step is accomplished by using in input the measurements taken in one of the preceding steps.