Signaling in control system

Abstract

A control system (100) comprises: a first control device (110); a plurality of second control devices (115); and a signal line (120) connecting the first control device and the second control devices (115) to each other. The first control device (110) is configured to determine a total current flowing through the signal line (120); and the second control device (115) is configured to cause a current flowing from the signal line (120), which current is a predetermined multiple of a predetermined reference current, in order to transmit the signal. In this case, different signals are assigned different multiples.

Description

Technical Field

[0001] This invention relates to a control system having a first control device and a plurality of second control devices. More particularly, this invention relates to transmitting signals in such a control system. Background Technology

[0002] Home appliances include a control system with multiple control devices. A first control device may perform central control tasks, while multiple second control devices may be designed for specific purposes. One of these second control devices may determine a status or event that should be signaled to the first control device. For example, one of these second control devices may determine a malfunction that it itself cannot eliminate or that would affect other control devices.

[0003] To enable rapid signal transmission between these control devices, an interrupt request can be transmitted. However, if data connections between these control devices are used for this purpose, ongoing data communication may delay the transmission of the interrupt request. Therefore, dedicated signal lines are typically used to transmit the interrupt request via signaling.

[0004] In one implementation, a dedicated signal line is assigned to each second control device. In another implementation, a common signal line is provided, on which a predetermined level is driven to send an interrupt request. Each of these second control devices can trigger this level, allowing the first control device to determine the interrupt request originating from each second control device. However, what may be difficult or time-consuming is determining the actual initiator of the interrupt request among these second control devices. Furthermore, this method does not support different priorities and cannot distinguish between urgent and less urgent interrupt requests.

[0005] In another embodiment, the signal line originates from the first control device and passes sequentially through these second control devices (daisy chain). To generate an interrupt request, the second control device can disconnect the signal line and set it to a predetermined level. Here, the order in which these second control devices are connected to each other determines the priority. However, this priority is hardwired and cannot be changed through configuration. Summary of the Invention

[0006] The objective of this invention is to provide an improved technique for transmitting signals from one control device to another. This objective is achieved through the subject matter of the independent claims. The dependent claims reflect preferred embodiments.

[0007] According to a first aspect of the invention, a control system includes: a first control device; a plurality of second control devices; and a signal line connecting the first control device and the second control devices to each other. The first control device is configured to determine the total current flowing through the signal line. The second control devices are configured to induce a current flowing through the signal line for transmitting a signal, the current being a predetermined multiple of a predetermined reference current. Here, different signals are assigned different multiples.

[0008] In this control system, multiple signals can be transmitted simultaneously via a single signal line. Each signal is represented by a current, where the individual currents are added together to form a total current. The first control device can determine the total current and infer the individual currents from it. Thus, it is possible to directly determine which combination of multiple signals should be transmitted via the signal line at a predetermined time.

[0009] In this way, states or events transmitted via signals can be processed quickly by a first control device. Since only a single signal line is required, the control system can be constructed simply and in a space-saving manner. The transmission does not use priority and can transmit all predetermined signals simultaneously. The order in which the first control device evaluates or responds to signals can be determined independently of the system architecture. This also supports reconfigurable prioritization.

[0010] The reference current can be determined based on the parameters of the control system. For example, the potential interference to the signal lines, such as interference with electromagnetic properties, or interference with the stability of the power supply to the control system, can be considered.

[0011] In a first variant of this control system, different multipliers are assigned to each of the second control devices. Here, a signal indicates one of these second control devices. Thus, these second control devices can concurrently provide signals to each other, each signal indicating that the relevant second control device requires the attention of the first control device.

[0012] In the second variant, different multiples are assigned to predetermined events or states. In this case, a single signal can indicate one of these events. Thus, events defined system-wide can be determined and signaled on different second control devices. This allocation can be advantageous, for example, in distributed or concurrent systems, or in systems where tasks are performed via distributed second control devices. In this variant, it is preferable to assign disjoint sets of signals to these second control devices to avoid different second control devices simultaneously providing the same signal.

[0013] Particularly preferred is that the different multiples are different integer powers of 2. In this way, these multiples can be 1, 2, 4, 8, 16, 32, etc. This allows for a better determination of individual currents based on the total current. Generally, it is preferred that all currents have the same sign. Preferably, the exponent of the integer power is also positive, but alternatively, a negative exponent can also be used. It is even more preferred that a series of consecutive integers is used as the power.

[0014] The first control device may include an analog-to-digital converter (ADC) configured to provide a binary representation of the determined total current, such that the bits of the binary representation correspond to a predetermined signal. Such ADCs are readily available at low cost and are already integrated into some microprocessors or microcontrollers. Thus, the total current can be quickly and easily decomposed into a superposition of signals.

[0015] The analog-to-digital converter (ADC) can have bit-level resolution exceeding several times its normal value, where at least one least significant bit is not evaluated. Measurement uncertainty in this ADC may manifest as one or more least significant bits not representing reliable information. Such effects can be filtered out by omitting one or more least significant bits (LSBs). For example, a 12-bit ADC can be used to decode the total current supplied by ten different secondary control devices. Each control device is allocated one bit of the ADC, where two least significant bits are not evaluated.

[0016] In one implementation, the total current includes a predetermined offset corresponding to half of the reference current. This offset can be persistently induced by the signal line. This allows for better filtering of positive and negative deviations between the measured values ​​and the sum of the currents provided by these second control devices. Such deviations could be caused, for example, by interference or noise.

[0017] In a particularly preferred embodiment, the first control device includes a voltage source connected to a signal line. The voltage supplied by the voltage source can be predetermined or determined by the first control device, for example, by means of another ADC. In one embodiment, the voltage supplied by the voltage source can be controlled by the first control device. At the first control device, the total current preferably flows through a resistor having a predetermined conductance. The voltage across the resistor is then proportional to the total current and can be determined relative to the supplied voltage.

[0018] Preferably, one of these second control devices is configured to induce a predetermined minimum current through the signal line. The first control device is configured to determine a fault in the signal line if the total current is lower than the minimum current. Failure to comply with the minimum current may, for example, result in an open circuit in the control line, which could interrupt signal transmission. Preferably, a signal current is also generated in addition to the minimum current, and the first control device determines the total current relative to the minimum current. The minimum current may include or be applied to the signal line in addition to the offset.

[0019] A further preferred approach is to have the minimum current caused by the second control device, which is furthest from the first control device on the control line. By maximizing the distance, any interference on the signal line can be detected, thus preventing undetected interference from occurring.

[0020] The control system includes a first control device and a plurality of second control devices, each configured to implement the techniques described herein. The first control device includes: a connection terminal for a signal line; a current sensor for determining the current flowing through the signal line; and a processing device configured to decompose the determined current into predetermined addends, each addend representing a signal, wherein the addend is a predetermined multiple of a predetermined reference current, and wherein different signals are assigned different multiples.

[0021] The second control device includes: a connection terminal for a signal line; a current sink for inducing current through the connection terminal, wherein the current is a predetermined multiple of a predetermined reference current; and a processing device for controlling the current sink according to a signal to be provided on the signal line. Here, different signals are assigned different multiples.

[0022] According to another aspect of the invention, a household appliance includes: the control system described herein, the first control device described herein, or the second control device described herein. The household appliance may include, for example, a kitchen appliance, a laundry and care appliance, or a refrigerator. Other appliances, particularly those used within the home, are also feasible.

[0023] According to another aspect of the invention, a method for transmitting a signal via a signal line connecting a first control device and a plurality of second control devices to each other includes the steps of: inducing a current from the signal line by one of the second control devices; wherein each current is a predetermined multiple of a reference current, and different multiples are assigned to different signals to be transmitted; determining the total current flowing through the signal line by the first control device; and determining the signal provided by the second control devices.

[0024] This method can be executed using a control system described herein. The control system may include one or more processing devices that can participate in the execution of the method. For this purpose, the processing devices may be implemented electronically and may, for example, include a programmable microcomputer or a microcontroller. The method may exist in the form of a computer program product with program code. This computer program product may also be stored on a computer-readable data carrier. Features or advantages of the method may be transferred to the device, or vice versa. Attached Figure Description

[0025] The invention will now be described in more detail with reference to the accompanying drawings, in which:

[0026] Figure 1 The control system is shown; and

[0027] Figure 2 A flowchart of the method is shown. Detailed Implementation

[0028] Figure 1 A control system 100 may be included in a household appliance 105. The household appliance 105 is illustrated exemplary as a washing machine; in other embodiments, any other household appliance 105 may also be equipped with the control system 100.

[0029] The control system 100 includes a first control device 110 and a plurality of second control devices 115. Preferably, these control devices 110 and 115 are implemented as microcomputers or microcontrollers, or include such devices. More preferably, the control system 100 is configured for distributed information processing, and particularly for controlling a household appliance 105. Preferably, the control system 100 is comprised of a single component in the household appliance 105. The component may include a circuit board with multiple parts. Particularly preferably, the control system, including all control devices 110 and 115, is implemented on an integrated circuit. The circuit may represent one of the parts of the component.

[0030] These control devices 110 and 115 are interconnected via a common signal line 120. Figure 1 Other connecting lines are not shown, such as those used for data transmission, or the common power supply or common grounding line between these control devices 110 and 115.

[0031] The following describes a technique for simultaneously transmitting multiple signals from one or more of the second control devices 115 to the first control device 110 via only one signal line 120. Here, the first control device 110 can decode the individual signals and preferably assign them to a separate source.

[0032] The first control device 110 includes a processing unit 125. A voltage source 130 is configured to apply a predetermined voltage to the signal line 120. A resistor 135 with a predetermined conductance is provided to determine the total current flowing through the signal line 120. The voltage across the resistor 135 can be determined by means of an analog-to-digital converter 140 and forwarded to the processing unit 125 in digital form. However, the current flowing through the signal line 120 can also be determined in other ways, such as through an inductor or based on a magnetic field around the signal line 120.

[0033] In some embodiments, the processing device 125 is configured to control the value of the voltage supplied by the voltage source 130. For this purpose, a digital-to-analog converter (DAC) may be included.

[0034] The second control device 115 includes a processing unit 145 and a current sink 150. The current sink 150 is configured to generate a predetermined current from the signal line 120. The processing unit 145 is configured to activate or deactivate the current sink 150. In some embodiments, the processing unit 145 can control the value of the current generated by means of the current sink 150.

[0035] In the illustrated embodiment, each second control device 115 is assigned an integer, which is indicated using hash symbols. These numbers start from zero and are arranged sequentially. Different second control devices 115 can be identified using these numbers.

[0036] Each second control device 115 is assigned a factor or multiple, which is a power of 2 here, having the assigned number as the exponent. Therefore, the second control device 115 shown above is assigned a factor of 2. 0 =1, the next second control device 115 is assigned a factor of 2. 1 =2, and the next second control device is assigned a factor of 2. 2 =4, and so on, until the second control device 115 shown below is assigned a factor of 2. N .

[0037] Each second control device 115 can generate an individual signal via signal line 120 by manipulating its corresponding current sink 150 to draw current from signal line 120, the current corresponding to the product of a predetermined factor and a predetermined reference current. Thus, a total current flows through signal line 120, which consists of individual, characteristic single currents. Here, each single current is twice the size of the adjacent smaller single current.

[0038] The total current flowing through signal line 120 can be determined by the first control device 110 by determining the voltage dropped across resistor 135. The determined value indicating the total current can then be decomposed into binary addends, where each binary addend corresponds to a single current that can be caused by one of the second control devices 115. This operation is essentially equivalent to converting the determined current into a binary value, where the least significant bit corresponds to a reference current. The processing device 125 can then identify which of the second control devices 115 transmitted the signal.

[0039] For example, if it is determined that a single reference current is flowing, the multiplier is one, and it can be determined that the second control device 115, numbered zero, is transmitting a signal. For a double reference current, the multiplier is two, making it possible to determine that the second control device 115, numbered one, is the cause. If both second control devices 115 in this example transmit signals simultaneously, the single and double reference currents are added together to form a total current, which corresponds to three times the reference current. Then, the first control device 110 can identify both second control devices 115 as simultaneous transmitters.

[0040] By representing it as a binary number, each bit of the binary representation can be directly assigned to one of these second control devices 115. Here, the least significant bit can be assigned to the second control device 115 numbered zero, the next more significant bit can be assigned to the second control device 115 numbered one, and so on. In this way, the signals of the second control devices 115 superimposed on the signal line 120 and represented by individual currents can be directly reconstructed into individual signals within the first control device 110.

[0041] To prevent erroneous results due to inaccurate measurements when determining the total current flowing through control line 120, the resolution of the analog-to-digital converter 140 for the flowing current can be set higher than the resolution required to determine these signals. In other words, preferably, the minimum resolvable difference of the analog-to-digital converter 140 is less than the value of the reference current.

[0042] For example, if four second control devices 115 are provided, the resolution of the ADC 140 can be six bits instead of four bits. Here, the two least significant bits can be ignored. Alternatively, by means of another current sink, preferably in the region of the first control device 110, an offset current can be induced via signal line 120, the magnitude of which is half the current represented by the least significant bit evaluated by the ADC 140. This prevents one or more bits of the determined representation of the total current from becoming unreliable due to interference such as noise.

[0043] It should be noted that in another embodiment, the different signals that can be transmitted via signal line 120 are not assigned to each of the second control devices 115, but are instead assigned to predetermined events or states. In this embodiment, each of these second control devices 115 can determine an event or state and transmit that event or state via a signal on signal line 120. To ensure that the same signal is not sent multiple times, thus making the decomposition of the total current no longer unique, different second control devices 115 can be assigned different signals, and these second control devices can each send these signals. Here, the corresponding available signal sets can be disjoint.

[0044] Figure 2 A flowchart of method 200 is shown, which can be performed in particular by means of control system 100. In a plurality of independent steps 205, different second control devices 115 can induce individual currents through signal line 120.

[0045] If a separate second control device 115 needs to transmit a signal to the first control device 110, the second control device can induce a predetermined current associated with it through the control line 120; otherwise, the current flowing through the control line 120 is left unaffected. The individual currents of these second control devices 115 are added together to form a total current. In step 210, the total current can be determined by the first control device 110. For this purpose, the voltage across the resistor through which the current flows can be determined. Here, the voltage across the signal line 120 can be kept constant at a predetermined value.

[0046] Now, in step 215, it can be determined whether the total current is greater than zero. If not, no signal is attached to control line 120. Otherwise, in step 220, the determined current can be decomposed into a binary addend. This can be simply achieved by representing the determined current as a binary number, where the least significant bit corresponds to the reference current. Each bit can be assigned a predetermined signal. If the value of the bit is one, a related signal exists; otherwise, no related signal exists.

[0047] In the first embodiment, each signal is assigned a different second control device 115. In step 225, it can be determined, based on the set bits, which of these second control devices 115 sends a signal to the first control device 110.

[0048] In the alternative second implementation, these signals are assigned to individual events or states. In this case, in step 230, it can be determined which events or states are simultaneously signaled based on the valid bits.

[0049] In both cases, a response can be made to the corresponding signal, event, or state in step 235. For this purpose, further communication can be made between control devices 110 and 115, typically via a means other than signal line 120.

[0050] Figure Labels

[0051] 100 Control System

[0052] 105 Home Appliances

[0053] 110 First Control Equipment

[0054] 115 Second Control Equipment

[0055] 120 signal line

[0056] 125 processing device

[0057] 130V source

[0058] 135 resistor

[0059] 140 Analog-to-Digital Converter

[0060] 145 Processing Unit

[0061] 150 Current Concentrator

[0062] 200 methods

[0063] 205 causes current

[0064] 210 Determine the total current

[0065] 215 Total current > 0?

[0066] 220 Decompose the current value into binary addends

[0067] 225. Identify Participants

[0068] 230 Confirmation Signal

[0069] 235 Handling Status

Claims

1. A control system (100), comprising: - A first control device (110); - Multiple second control devices (115); and - Signal line (120), which connects the first control device and the second control device (115) to each other. - Wherein, the first control device (110) is configured to: determine the total current flowing through the signal line (120), -The second control device (115) is configured to: in order to transmit a signal, cause a current to flow through the signal line (120), the current being a predetermined multiple of a predetermined reference current. - Different signals are assigned different multiples.

2. The control system (100) according to claim 1, wherein, Different multiples are assigned to the second control devices (115); and a signal indicates one of the second control devices (115).

3. The control system (100) according to claim 1, wherein, Different multiples are assigned to predetermined events; and a signal indicates one of the events.

4. The control system (100) according to any one of the preceding claims, wherein, Different multiples are different integer powers of 2.

5. The control system (100) according to claim 4, wherein, The first control device (110) includes an analog-to-digital converter (140) to provide a binary representation of the determined total current, such that bits of the binary representation correspond to a predetermined signal.

6. The control system (100) according to claim 5, wherein, The analog-to-digital converter (140) has a resolution in bits that exceeds a number of different multiples; wherein at least one least significant bit is not evaluated.

7. The control system (100) according to any one of the preceding claims, wherein, The first control device (110) includes a voltage source (130) connected to the signal line (120).

8. The control system (100) according to any one of the preceding claims, wherein, One of the second control devices (115) is configured to cause a predetermined minimum current through the signal line (120); wherein the first control device (110) is configured to determine that a fault exists in the signal line (120) if the total current is lower than the minimum current.

9. The control system (100) according to claim 8, wherein, The second control device (115), which is furthest from the first control device (110) relative to the control line (120), causes the minimum current.

10. A first control device (110), comprising: - Connecting terminals for signal lines (120); - Current sensor (135) for determining the current flowing through the signal line (120); and - Processing device (125), the processing device being configured to decompose the determined current into predetermined addends, the addends representing signals respectively. - Wherein, the addend is a predetermined multiple of the predetermined reference current, and different signals are assigned different multiples.

11. A second control device (115), comprising: - Connecting terminals for signal lines (120); - Current sink (150), used to generate current through the connection terminal - Wherein, the current is a predetermined multiple of a predetermined reference current; and - Processing device (145) for controlling the current sink according to the signal to be provided on the signal line (120), - Different signals are assigned different multiples.

12. A household appliance (105), comprising: The control system (100) according to any one of claims 1 to 9; or the control device (110) according to claim 10; or the control device (115) according to claim 11.

13. A method (200) for transmitting signals via a signal line (120) connecting a first control device (110) and a plurality of second control devices (115) to each other, wherein, The method includes the following steps: - A current (205) is generated from the signal line (120) by one of the second control devices (115), -In this context, each current is a predetermined multiple of the reference current, and different multiples are assigned to different signals to be transmitted; - The total current flowing through the signal line (120) is determined by the first control device (110); and - Determine (225, 230) the signals provided by the second control device (115).

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