Sensor assembly that outputs the sensor status

Abstract

To provide a sensor assembly that outputs a state of a sensor.SOLUTION: A sensor assembly 10 comprises: a sensor 100 that generates a sensor signal; an output unit 200 and a state unit 300 that receive a sensor signal 130 output from the sensor 100; and a test line 400 connected to the sensor 100 and the state unit 300. The output unit 200 outputs a signal output 270 representing a state detected by the sensor 100. The state unit 300 outputs a state output 380 representing the state of the sensor 100. The test line 400 is bidirectional and outputs the state output 380.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a sensor assembly, and more particularly to a sensor assembly that outputs a status of a sensor in the sensor assembly. [Background technology]

[0002] A sensor in a sensor assembly typically has an output line or pin and an input line or pin. A signal representative of a variable sensed by the sensor is output on the output line. The input line is used to input a self-test signal to the sensor to determine if the sensor is functioning properly, and in response to receiving the self-test signal, the sensor outputs a predetermined signal that can be evaluated to determine if the sensor is in a fault condition. Summary of the Invention [Problem to be solved by the invention]

[0003] Although the self-test can indicate a sensor failure, the sensor's status is output on demand only upon receipt of a self-test signal. Otherwise, the sensor's status is unknown and the sensor may output an unreliable signal prior to the failure determination initiated by the self-test signal. Furthermore, evaluation of a given signal output by the sensor in a self-test only indicates whether the sensor is operational or whether the sensor has already reached a failure state. The sensor's output prompted by the self-test signal cannot give an intermediate indication when the sensor is approaching failure. [Means for solving the problem]

[0004] The sensor assembly includes a sensor generating a sensor signal, an output unit and a status unit receiving the sensor signal output from the sensor, and a test line connected to the sensor and the status unit. The output unit outputs a signal output representative of a state detected by the sensor. The status unit outputs a status output representative of a state of the sensor. The test line is bidirectional and outputs the status output.

[0005] The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic block diagram of a sensor assembly according to one embodiment. [Diagram 2] FIG. 2 is a schematic block diagram of an output unit of the sensor assembly. [Diagram 3] FIG. 2 is a schematic block diagram of a state unit of the sensor assembly. [Figure 4A] 1 is a graph of a main signal and a baseline signal of a sensor of a sensor assembly, along with a first threshold and a second threshold. [Figure 4B] FIG. 4B is an enlarged view of portion B of the graph in FIG. 4A. [Diagram 5] 1 is a flow chart of a method for outputting a sensor status using a sensor assembly. [Figure 6] FIG. 13 is a schematic block diagram of a sensor assembly according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals refer to the same elements. However, the present disclosure can be embodied in many different forms and should not be construed as being limited to the embodiments described herein. Rather, these embodiments are provided so that the present disclosure conveys the concept of the present disclosure to those skilled in the art. In addition, in the following detailed description, for the purpose of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, it is clear that one or more embodiments can be implemented without these specific details.

[0008] A sensor assembly 10 according to one embodiment is shown in Figure 1. The sensor assembly 10 comprises a sensor 100, an output unit 200 connected to the sensor 100, a status unit 300 connected to the sensor 100, a test line 400 connected to the status unit 300 via a switch 600, and a signal line 500 connected to the output unit 200.

[0009] 1, the sensor 100 includes a sensing element 110 and a signal conditioner 120. The sensing element 110 senses the state of a measured variable, and the signal conditioner 120 interacts with the sensing element 110 based on a drive signal to generate and output a sensor signal 130 representative of the state sensed by the sensing element 110.

[0010] In one embodiment, signal conditioner 120 is a piezoelectric crystal that generates ultrasonic waves and sensing element 110 is a piezoelectric crystal that receives the ultrasonic waves and converts the ultrasonic waves into an electrical signal based on a condition sensed by sensing element 110. In another embodiment, sensing element 110 and signal conditioner 120 may be a single piezoelectric transceiver operating, for example, in a pulse-echo mode. In further embodiments, signal conditioner 120 may be any type of element that provides an excitation signal and sensing element 110 may be any type of element that provides a response signal representative of a condition sensed by sensing element 110 in response to the excitation signal from signal conditioner 120. In various embodiments, signal conditioner 120 may further include components for voltage conditioning, filtering, amplification, and / or buffering, provided that signal conditioner 120 receives the state of the measured variable from sensing element 110 and outputs sensor signal 130 as a measurable electrical signal, such as a voltage signal. In one embodiment, switch 600, described in more detail below, may be part of signal conditioner 120.

[0011] In one embodiment, the sensing element 110 detects the presence of moisture, for example, whether the liquid filling a tube has air bubbles present in the liquid (which is otherwise wet but dry), such as in medical applications, etc. In other embodiments, the sensing element 110 can detect acceleration, force, vibration, pressure, or other measured variables for various applications.

[0012] In a normal operating state N of the sensor assembly 10, the sensor 100 outputs a sensor signal 130 to each of the output unit 200 and the status unit 300. First, the normal operating state N will be described in more detail, followed by a description of the self-test state S of the sensor assembly 10.

[0013] As shown in FIG. 1, in a normal operating state N, the output unit 200 receives the sensor signal 130 output from the sensor 100 and outputs a signal output 270 representative of the sensor signal 130 and the condition detected by the sensor signal 130 .

[0014] As shown in Fig. 2, the output unit 200 includes a first output voltage divider 210, a second output voltage divider 220, and a first output comparator 230 connected to the first output voltage divider 210 and the second output voltage divider 220. The first output voltage divider 210 and the second output voltage divider 220 each receive the sensor signal 130. The first output voltage divider 210 outputs a main signal 132, which directly represents the sensor signal 130 and changes with the sensor signal 130. In the illustrated embodiment, the second output voltage divider 220 filters or delays the sensor signal 130 to generate a baseline signal 134, which has a longer time constant or a dynamic response or change at a lower frequency than the sensor signal 130 and the main signal 132.

[0015] 4A and 4B, which show that the primary signal 132 is a more dynamic response of the conditions detected by the sensor 100 than the baseline signal 134. In various embodiments, the sensor 100 may be any type of sensor 100 having a baseline signal 134 indicative of overall sensor behavior, performance, or efficiency, and a primary signal 132 that is more dynamically indicative of the measured conditions detected by the sensing element 110.

[0016] 2 compares the main signal 132 to the baseline signal 134 and outputs a first output comparison 232 that indicates whether the main signal 132 is greater than or less than the baseline signal 134. In one embodiment, the first output comparison 232 is a voltage signal. In the exemplary graphs of the main signal 132 and the baseline signal 134 shown in FIGS. 4A and 4B, the first output comparison 232 changes as the main signal 132 changes over time to be greater or less than the baseline signal 134.

[0017] As shown in Fig. 2, the output unit 200 includes a voltage reference 240 and a second output comparator 250 connected to the voltage reference 240. The voltage reference 240 may be any type of electronic component that outputs a reference voltage 242 having a preset value. The second output comparator 250 receives the sensor signal 130 and the reference voltage 242, and compares the sensor signal 130 with the reference voltage 242. The second output comparator 250 outputs a second output comparator 252 that indicates whether the sensor signal 130 is greater than or less than the reference voltage 242.

[0018] As shown in FIG. 2, the output unit 200 includes an output level detection circuit 260 that receives a first output comparison 232 from a first output comparator 230 and a second output comparison 252 from a second output comparator 250. The output level detection circuit 260 outputs a signal output 270 based on the first output comparison 232 and the second output comparison 252. If the first output comparison 232 indicates that the baseline signal 134 is greater than the main signal 132, the output level detection circuit 260 outputs the signal output 270 in a first state. Conversely, if the first output comparison 232 indicates that the main signal 132 is greater than the baseline signal 134, the output level detection circuit 260 outputs the signal output 270 in a second state. An exemplary relationship between the main signal 132 and the baseline signal 134 over time that determines the state of the signal output 270 is shown in FIG. 4B.

[0019] The second output compare 252 sent to the output level detection circuit 260 prevents problems with the first output comparator 230 from affecting the signal output 270. If the first output comparator 230 is oscillating or malfunctioning, the output level detection circuit 260 will always indicate one of the first and second states of the signal output 270 via the second output compare 252.

[0020] In one embodiment, the signal output 270 in a first state is a 0V signal indicating a wet condition, for example in a liquid in a tube sensing application, and in a second state is a 5V signal indicating, for example, a dry condition or an air bubble in the liquid in the tube. In other embodiments, the voltages of the signal output 270 used to indicate the first and second states may be swapped or otherwise have different values.

[0021] As shown in FIG. 1, in a normal operating state N, the state unit 300 receives the sensor signal 130 output from the sensor 100 and outputs a status output 380 representing the state of the sensor 100 .

[0022] 3, the state unit 300 includes a first state voltage divider 310 and a second state voltage divider 320, each of which receives the sensor signal 130. The first state voltage divider 310 and the second state voltage divider 320 each filter or delay the sensor signal 130 to output the baseline signal 134 described above.

[0023] 3, the state unit 300 includes a first state comparator 330 connected to a first state voltage divider 310, a first threshold voltage divider 350, a second state comparator 340 connected to a second state voltage divider 320, and a second threshold voltage divider 360. The first threshold voltage divider 350 outputs a first threshold 352, which is a preset voltage value, to the first state comparator 330, and the second threshold voltage divider 360 outputs a second threshold 362, which is a preset voltage different from the first threshold 352, to the second state comparator 340. Each of the first threshold voltage divider 350 and the second threshold voltage divider 360 can receive a voltage from a source internal or external to the sensor assembly 10 and output the first threshold 352 and the second threshold 362. 4A, the first threshold 352 may be approximately 0.3 V and the second threshold 362 may be approximately 1.3 V. In other embodiments, the first threshold 352 and the second threshold 362 may have other values, so long as the values ​​are different from each other and the second threshold 362 is greater than the first threshold 352.

[0024] 3 compares the baseline signal 134 with a first threshold 352 and outputs a first state comparison 332 indicative of whether the baseline signal 134 is greater than or less than the first threshold 352. Similarly, the second state comparator 340 compares the baseline signal 134 with a second threshold 362 and outputs a second state comparison 342 indicative of whether the baseline signal 134 is greater than or less than the second threshold 362. In one embodiment, the first state comparison 332 and the second state comparison 342 are each voltage signals.

[0025] 3, the state unit 300 includes a state level detection circuit 370 that receives a first state comparison 332 from the first state comparator 330 and a second state comparison 342 from the second state comparator 340. The state level detection circuit 370 outputs a state output 380 based on the first state comparison 332 and the second state comparison 342. The state output 380 represents one of three states of the sensor 100. That is, if the first state comparison 332 and the second state comparison 342 indicate that the baseline signal 134 is greater than both the first threshold 352 and the second threshold 362, the state output 380 is in a first state, if the baseline signal 134 is greater than the first threshold 352 and less than the second threshold 362, the state output 380 is in a second state, and if the baseline signal 134 is less than both the first threshold 352 and the second threshold 362, the state output 380 is in a third state. An exemplary relationship of the baseline signal 134 and the thresholds 352, 362 over time that dictates the state of the state output 380 is shown in FIG.

[0026] In the illustrated embodiment, the baseline signal 134 is compared to a lower first threshold 352 and a higher second threshold 362. In another embodiment, where the baseline signal 134 is allowed to increase beyond a desired amount, the baseline signal 134 may be compared to a pair of first thresholds 352 and a pair of second thresholds 362. In this embodiment, a baseline signal 134 between the second thresholds 362 indicates a first condition, a baseline signal 134 between one of the second thresholds 362 and one of the first thresholds 352 indicates a second condition, and a baseline signal 134 outside either of the first thresholds 352 indicates a third condition.

[0027] In one embodiment, in a first state, the status output 380 is a 0V signal indicating, for example, a normal state of the sensor 100, in a second state, a 1.25V signal indicating, for example, a marginal state of the sensor 100, and in a third state, a 2.5V signal indicating, for example, a fault state of the sensor 100. In another embodiment, the status output 380 may be a 2.5V signal in both the second and third states. In further embodiments, the voltages of the status output 380 used to indicate the three states may be swapped or may otherwise have different values.

[0028] 1 are two lines connected to the sensor 100 along which a signal is sent. The test line 400 and the signal line 500 may each be a transistor-transistor logic (TTL) line. Although the test line 400 and the signal line 500 are referred to herein as "lines," in alternative embodiments, the test line 400 and the signal line 500 may be two pins connected to the sensor 100 along which a signal is sent. In the illustrated embodiment, the test line 400 and the signal line 500 are simply two lines or pins along which a signal may be sent to and from the sensor 100.

[0029] 1, a test line 400 is connected to the sensor 100 through the state unit 300 and also to a switch 600. The test line 400 is bidirectional. In a normal operating state N, the test line 400 receives a status output 380 from the state unit 300 and outputs a status output 380. A self-test input 410 may also be input to the test line 400, which may trigger a switch 600 to change the sensor assembly 10 from the normal operating state N to a self-test state S, as will be described in more detail below.

[0030] 1, the signal line 500 is connected to the sensor 100 and the output unit 200. The signal line 500 is unidirectional, i.e. it cannot receive input and outputs the signal output 270 received from the output unit 200.

[0031] 1 may be any type of electrical circuit switch capable of switching when a threshold voltage is exceeded. In one embodiment, switch 600 is a metal oxide semiconductor field effect transistor (MOSFET) switch. The threshold voltage of switch 600 is greater than the voltage of all states of status output 380 and less than the voltage of self-test input 410. In one embodiment, the threshold voltage is between 2.5V and 5V.

[0032] Referring now primarily to FIG. 5, a method 700 of using the sensor assembly 10 to output a status of the sensor 100 will now be described in more detail.

[0033] The sensor assembly 10 starts in a normal operating state N. In a first step 702 in the normal operating state N shown in Fig. 5, the sensor 100 outputs the sensor signal 130 to the output unit 200 and the state unit 300 as previously described, as shown in Fig. 1. In the normal operating state N, the sensor 100 continuously outputs or sends the sensor signal 130 to both the output unit 200 and the state unit 300.

[0034] In step 704 of Figure 5, the output unit 200 outputs the signal output 270 representing the sensor signal 130 and the state detected by the sensor signal 130 to the signal line 500, as described above with respect to Figure 2. Similarly, in step 706, the state unit 300 outputs the status output 380 representing the state of the sensor 100 to the test line 400, as described above with respect to Figure 3. The status output 380 has a sufficiently low voltage, and the switch 600 is not triggered in step 706. In normal operating state N, the output unit 200 continuously outputs the signal output 270 to the signal line 500, and the state unit 300 continuously outputs the status output 380 to the test line 400.

[0035] 5, the signal output 270 is evaluated. The signal output 270 represents a condition detected by the sensor 100 in the sensor signal 130, and the significance of the first or second state of the signal output 270 depends on the application. For example, in an exemplary liquid bubble detection application, the second state of the signal output 270 may indicate a dry condition or an air bubble in the liquid in the tube, which may prompt an alarm or other action, while the first state of the signal output 270 may indicate a normal wet condition of the liquid in the tube. In other applications of the sensor assembly 10, the first and second states of the signal output 270 may prompt different actions.

[0036] 5, the status output 380 is evaluated. A first state of the status output 380 indicates a normal state of the sensor 100, where the sensor 100 is operating normally. A second state of the status output 380 indicates a marginal condition of the sensor 100, where the sensor 100 can continue to operate and provide a useful signal output 270, but the marginal condition indicates that the sensor 100 is approaching failure. A third state of the status output 380 indicates a fault condition of the sensor 100, where the signal output 270 is unreliable.

[0037] 5, the sensor assembly 10 remains in the normal operating state N and continuously outputs both the signal output 270 and the status output 380 unless the self-test input 410 is input to the test line 400 in step 712 shown in FIG.

[0038] In step 714 shown in FIG. 5, the self-test input 410 is sent along the test line 400 to the switch 600. The self-test input 410 is greater than the activation threshold of the switch 600, activating the switch 600. When the switch 600 is activated, the drive disable signal 610 from the switch 600 to the signal conditioner 120 disables the drive signal of the signal conditioner 120, so that the sensor 100 outputs the self-test output 140 shown in FIG. 1 instead of the sensor signal 130, as shown in step 716 of FIG. 5. The self-test output 140, as determined by the drive disable signal 610, is a default value. In the self-test state S, the switch 600 bypasses the state unit 300, and in the self-test state S, the state output 380 is not output to the test line 400.

[0039] In the self-test state S, the self-test output 140 is processed by the output unit 200 and output as a signal output 270 on the signal line 500. In step 718 of the self-test state S shown in FIG. 5, the signal output 270, which represents the self-test output 140, is compared to the self-test input 410. The self-test output 140 is such that it generates a signal output 270 that matches the self-test input 410. If in the self-test state S the signal output 270 does not match the self-test input 410, then a fault condition of the sensor 100 can be determined.

[0040] 5, the sensor assembly 10 remains in the self-test state S and continues to evaluate the signal output 270 for a fault condition of the sensor 100 as long as the self-test input 410 is applied to the test line 400. Once the self-test input 410 is no longer applied to the test line 400, the switch 600 is returned and the sensor assembly 10 proceeds in the normal operating state N as shown in FIG.

[0041] The sensor assembly 10 remains in the normal operating state N or the self-test state S until the sensor assembly 10 is deactivated, for example, due to a determination of a fault condition of the sensor 100 at step 710 at the normal operating state N or step 718 at the self-test state S.

[0042] In the sensor assembly 10 shown in Figures 1-5, the output unit 200, the state unit 300 and the switch 600 achieve the above functions without the need for a microprocessor, thereby reducing the cost of the sensor assembly 10. In another embodiment of the sensor assembly 10' shown in Figure 6, a controller 800 can perform the functions of the output unit 200, the state unit 300 and the switch 600 described above. Compared with the embodiment shown and described above with respect to Figures 1-5, the same reference numerals refer to the same elements, and the differences of the embodiment shown in Figure 6 with respect to the controller 800 will be mainly described in detail.

[0043] 6, the controller 800 includes a processor 810 and a memory 820 coupled to the processor 810. The memory 820 is a non-transitory computer-readable medium that stores a number of algorithms as modules that perform the functions of the modules described herein when executed by the processor 810. The memory 820 stores an output module 822, a state module 824, and a switch module 826. The output module 822 performs all the functions of the output unit 200 described above when executed by the processor 810, the state module 824 performs all the functions of the state unit 300 described above when executed by the processor 810, and the switch module 826 performs all the functions of the switch 600 described above when executed by the processor 810. Thus, the controller 800 enables the sensor assembly 10' to perform the same functions as the sensor assembly 10 described above, by continuously outputting both the signal output 270 on the signal line 500 and the status output 380 on the test line 400 in the normal operating state N, and by outputting the signal output 270 representative of the self-test output 140 of the sensor 100 in the self-test state S, but with fewer components.

[0044] The sensor assembly 10, 10' according to the above-described embodiment allows for a more reliable determination of the status of the sensor 100 without adding communication lines to the sensor assembly 10, 10'. The sensor assembly 10, 10' continuously outputs the status output 380 and also the signal output 270 on the signal line 500 to provide the status of the sensor 100 prior to the self-test input 410 on demand. The sensor assembly 10, 10' can also indicate a marginal condition on the status output 380 prior to a fault condition to warn of an impending failure while the sensor 100 is still outputting a valid signal output 270. The sensor assembly 10, 10' further allows for initiation of a self-test state S via the bidirectional test line 400.

Claims

1. A sensor assembly (10), comprising: a sensor (100) generating a sensor signal (130); an output unit (200) for receiving the sensor signal (130) output from the sensor (100) and for outputting a signal output (270) representative of a condition detected by the sensor (100); a state unit (300) that receives the sensor signal (130) output from the sensor (100) and outputs a state output (380) that represents a state of the sensor (100); a test line (400) connected to said sensor (100) and said status unit (300); The test line (400) is bidirectional; A sensor assembly (10), wherein in a normal operating state (N) of the sensor assembly (10), the test line (400) outputs the status output (380) output by the status unit (300).

2. 2. The sensor assembly (10) of claim 1, further comprising a signal line (500) connected to the sensor (100) and the output unit (200), the signal line (500) being unidirectional and outputting the signal output (270).

3. A sensor assembly (10) as described in claim 2, wherein, in the normal operating state (N), the output unit (200) continuously outputs the signal output (270) to the signal line (500) and the status unit (300) continuously outputs the status output (380) to the test line (400).

4. The sensor assembly (10) of claim 1, wherein the status output (380) represents one of a normal state, a marginal state, and a fault state of the sensor (100).

5. The sensor assembly (10) of claim 4, wherein the limit condition indicates that the sensor (100) is approaching failure.

6. a baseline signal (134) is generated by filtering or delaying the sensor signal (130) in a voltage divider (310, 320) of the state unit (300); 5. The sensor assembly of claim 4, wherein the status unit compares the baseline signal to a plurality of thresholds to determine whether the status of the sensor is the normal status, the marginal status, or the fault status.

7. 2. The sensor assembly of claim 1, wherein the signal output represents one of a pair of conditions detected by the sensor, and when the sensor signal is received by the output unit, a main signal is output and a baseline signal is generated by filtering or delaying the sensor signal in a voltage divider, and the output unit compares the main signal with the baseline signal to determine the condition detected by the sensor.

8. 4. The sensor assembly (10) of claim 3, further comprising a switch (600) connected between the sensor (100) and the test line (400), the switch (600) receiving a self-test input (410) along the test line (400) to switch between the normal operating state (N) and a self-test state (S) of the sensor assembly (10).

9. The sensor assembly (10) of claim 8, wherein in the normal operating condition (N), the status output (380) is sent to the test line (400) without triggering the switch (600).

10. 10. The sensor assembly (10) of claim 9, wherein in the normal operating state (N), the state unit (300) outputs the status output (380) to the test line (400), and in the self-test state (S), the state unit (300) does not output the status output (380) to the test line (400), and in the self-test state (S), the sensor (100) outputs a self-test output (140), the self-test output (140) being determined by a drive disable signal (610) sent from the switch (600) to a signal conditioner (120) of the sensor (100).

11. In the self-test state (S), The sensor assembly (10) of claim 10, wherein the sensor (100) outputs the self-test output (140) to the output unit (200) and not to the status unit (300).

12. 2. The sensor assembly (10) of claim 1, wherein the output unit (200) and the status unit (300) each have a plurality of voltage dividers (210, 220, 310, 320), a comparator (230, 330, 340), and a level detection circuit (260, 370) to generate the signal output (270) and the status output (380) from the sensor signal (130).

13. The sensor assembly (10) of claim 1, wherein the output unit (200) and the state unit (300) are executed by a controller (800).

14. A method (700) for outputting a state of a sensor (100), comprising: providing a sensor assembly (10) including the sensor (100), an output unit (200) connected to the sensor (100), a status unit (300) connected to the sensor (100), and a test line (400) connected to the sensor (100) and to the status unit (300), the test line (400) being bidirectional; sending a sensor signal (130) of said sensor (100) to said output unit (200) and to said status unit (300); using said output unit (200) to output a signal output (270) representative of a condition detected by said sensor (100); using said status unit (300) to output a status output (380) representative of the status of said sensor (100) to said test line (400); Including, In a normal operating state (N) of the sensor assembly (10), the test line (400) outputs the status output (380) output by the status unit (300).

15. The method of claim 14, wherein in the normal operating state (N), the output unit (200) continuously outputs the signal output (270) to a signal line (500) connected to the sensor (100) and the output unit (200), and the state unit (300) continuously outputs the status output (380) to the test line (400), the status output (380) representing one of a normal state, a limit state, and a fault state of the sensor (100).

16. 16. The method of claim 15, further comprising switching the sensor assembly (10) between the normal operating state (N) and a self-test state (S) based on a self-test input (410) received along the test line (400), wherein in the self-test state (S), the state unit (300) does not output the status output (380) to the test line (400) and the sensor (100) outputs a self-test output (140).

17. In the self-test state (S), 17. The method of claim 16, wherein the sensor (100) outputs the self-test output (140) to the output unit (200) and not to the status unit (300).

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