FIELD OF INVENTION

This invention relates to a device for establishing communication between a thermostat and a system. In particular, the device is capable of allowing communication between thermostats and HVAC systems of incompatible power supplies in terms of voltages and current types as well as control signal forms.

BACKGROUND OF THE INVENTION

Thermostats maintain a desired temperature range within an area through detecting temperature change in order to adjust temperature settings of thermostatically controlled systems that heat or cool to a setpoint temperature. These adjustments can be done by transferring electrical signals from the thermostat to instruct the system to change its operation mode that includes heating, cooling or fan speed adjustment.

A variety of thermostats have been introduced in the market over the years such as manual thermostats which are electromechanically operated, programmable thermostats that permit scheduling and programming of the activation and temperature settings of the systems, and smart thermostats which are equipped with programmable functions, learning capabilities for learning heating and cooling habits of users, and wireless connectivity for allowing control of the system to be conducted remotely.

Heating, ventilation and air conditioning (HVAC) systems that belong to a thermostatically controlled system are usually provided with thermostats. However, pairing up of external thermostats to HVAC systems is also possible, but only limited to designated thermostats that are customized to work with these HVAC systems. In other to expand the range of applicable thermostats for HVAC systems, incompatibility issues between the thermostats that are not designed for use with certain HVAC systems need to be solved. US20140084072A1 discloses an auxiliary HVAC control unit for solving size incompatibility issue for the thermostat that is incapable of occupying receivers for more wire connections with the HVAC system, as well as accommodating more circuitries for increasing adjustable operation mode functions. Such incompatibility issue addressed by US20140084072A1 lies on the physical aspect of the thermostat itself and is unrelated to power supply and control signal form incompatibility as the invention in US20140084072A1 only supports the connection of one or more thermostats and HVAC systems that operate in compatible power supplies in terms of similar voltage and current type through the auxiliary HVAC control unit. The auxiliary HVAC control unit serves as an additional body to provide more space for wire connections and accommodate more circuits for additional operation mode functions. The auxiliary HVAC control unit is not applicable to play the role as an intermediary to pair up thermostats and HVAC systems of incompatible power supply and control signal form, and act as a translator to translate signals between the thermostat and HVAC system for establishing communication between the two.

It is therefore important to introduce a device for allowing communication between thermostat and HVAC system that operate in different power supply such as voltage and/or current type from each other.

SUMMARY OF INVENTION

The present invention discloses a device for establishing communication between a thermostat and a thermostatically controlled system that comprises a communication circuit configured for translating instruction signals from the thermostat that each corresponds to an operation mode into commands recognisable by the thermostatically controlled system to manipulate its operation mode; wherein the communication circuit supports communication of the thermostat with the thermostatically controlled system that operates at an incompatible power supply in terms of voltage and current type, as well as control signal form with the thermostat.

In a preferred embodiment, the communication circuit comprises at least one signal receiver for receiving each instruction signal of a first voltage and a first form from the thermostat; a signal transfer component for transferring the instruction signal from the first voltage to a second voltage; and a control unit for converting the instruction signal of the second voltage from the first form to a second form, in which the instruction signal of the second voltage and second form defines the recognisable command.

Preferably, the signal transfer component is an electrical isolated component being an optocoupler or a relay.

According to the preferred embodiment, the thermostat operates at the first voltage, whereas the device operates at the second voltage.

It is preferred that the first voltage is 24 volts and the second voltage is 5 volts.

In addition, it is preferred that the first form is analog, whereas the second form is digital.

Preferably, the device is connected to the thermostatically controlled system by a transferring wire and a receiving wire.

Besides that, either or both of the thermostat and the device receive power supply preferably from the thermostatically controlled system. The operation mode can be any one or a combination of cooling, heating, low fan speed, medium fan speed and high fan speed.

In accordance with the preferred embodiment, the thermostatically controlled system is a heating, ventilation and/or air conditioning system.

Another aspect of the present invention provides a method for establishing communication between a thermostat and a thermostatically controlled system that comprises the step of translating instruction signals from the thermostat that each corresponds to an operation mode into commands recognizable by the thermostatically controlled system to manipulate its operation mode through a communication circuit of a device as described above; wherein the communication circuit supports communication of the thermostat with the thermostatically controlled system that operates at an incompatible power supply in terms of voltage and current type with the thermostat.

Accordingly, the present invention is targeted at establishing communication between thermostats with incompatible thermostatically controlled systems with respect to power supply that includes voltage and current type with the incorporation of a device that functions as a gateway between the thermostat and system. These third-party thermostats include a broad range of thermostats including manual, programmable and smart thermostats that are not designed to be compatible with the thermostatically controlled systems. To offer such solution for establishing communication, the present invention is capable of translating signals from the thermostat into a command recognisable by the thermostatically controlled system in order to manipulate operation mode of the system. Through the device introduced herein, the signals from the thermostat that are powered at a different voltage and transformed in a different form can be accepted and read by the thermostatically controlled system through the translation process that requires the steps of receiving, decoding and encoding the signals. Further, there is no need for modifying hardware of these existing third-party thermostats to communicate with the system. However, it should be noted that communication can also be established between thermostats and thermostatically controlled systems that are compatible in power supply, whereby they are both powered at the same voltage and current type.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention will now be described in greater detail with reference to the accompanying drawings.

Figure 1 shows a schematic diagram of the thermostatically controlled system connected to a thermostat through a device that acts as a gateway between the system and the thermostat.

DETAILED DESCRIPTION OF THE INVENTION

For a better understanding of the invention, preferred embodiments of the invention that are illustrated in the accompanying drawings will be described in detail.

The present invention disclosed herein is a device (100) functioning as a gateway between a thermostat (200) and a thermostatically controlled system (300) for maintaining temperature within a desired range in an area. In this disclosure, the method for establishing communication between the thermostat (200) and the thermostatically controlled system (300) is described. In operation, when a temperature change occurs within the area, the thermostat (200) sends signals to manipulate operation mode of the thermostatically controlled system (300).

Since the thermostat (200) is not limited to a certain type of thermostat (200), it can be any type of thermostats (200) including manual, programmable or smart thermostat that are incompatible with the thermostatically controlled system (300) in terms of power supply and control signal form. In other words, the applicable thermostat can operate at an incompatible power supply if the thermostat (200) is powered by a different voltage and/or current type from the thermostatically controlled system (300). Thus, the term ‘power supply’ here refers to electrical quantities of voltage and current type that can be direct current or alternating current.

On the other hand, the thermostatically controlled system (300) refers to a thermostatically controlled load that consume electricity for heating or cooling purposes such as heating, ventilation, and/or air conditioning (HVAC or AC) system, heater, cooler, refrigerators, incubators. However, to facilitate understanding of the present invention, a heating, ventilation, and air conditioning (HVAC) system shall be used as an example throughout this disclosure including the accompanying drawings.

An important feature of the device (100) is that it serves to translate communication between thermostats (200) that are supplied with power that are incompatible with the thermostatically controlled systems (300). Such thermostats (200) are referred as ‘third- party thermostats’. In an exemplary embodiment of the present invention, the thermostat (200) is powered at 24 volts alternating current (VAC) which is equivalent to 34 volts peak (34V _peak ) whereas the thermostatically controlled system (300) that is an HVAC system operates at 12 volts direct current (VDC). Although the thermostat (200) can be powered by an external power source, it is preferred that the thermostat (200) obtains power derived from the thermostatically controlled system (300) through the device (100) that performs the power conversion task. In Figure 1, the components and wires (500) involved in power supply are shown.

Communication from the thermostat (200) to the thermostatically controlled system (300) is mainly for manipulating operation mode of the thermostatically controlled system (300) based on instructions that are input at the thermostat (200). Whilst the instructions can be keyed in, it is preferred that means (210) such as buttons for selection of operations modes are presented at the external surface of the thermostat (200). Referred to Figure 1, the operation mode includes, but is not limited to any one or a combination of cooling that is denoted as ΎG, heating that is denoted as ‘Wl\ low fan speed that is denoted as ‘G’, medium fan speed that is denoted as ‘FI’ and high fan speed that is denoted as ‘F2\ Other than the denotations for the medium and high fan speed (FI, F2), the denotations stated above are based on standard terminal labels of the operation modes for thermostats (200). Upon selecting a desired operation mode, whether it is through manual selection or automatic selection if the operation mode is programmed, an output signal being an instruction signal is generated for each selection of operation mode to represent an operation request of a user.

As a translator for the thermostatically controlled system (300) to recognise the instruction signal, the device (100) comprises a communication circuit configured for translating instruction signals from the thermostat (200) that each corresponds to an operation mode into commands recognisable by the thermostatically controlled system (300) to manipulate its operation mode. Based on a preferred embodiment of the invention, the communication circuit comprises at least one signal receiver for receiving each instruction signal of a first voltage and a first form from the thermostat (200). The signal receivers include ports (110) for signal wires (410) connecting from the thermostat (200) to the device (100). The ports (110) shown in Figure 1 are labelled based on the operation modes available to be selected at the thermostat (200).

Upon receiving the instruction signal from the signal receiver, a signal transfer component (120) being part of the communication circuit and connected to the signal receiver, is used for transferring the instruction signal from a first voltage to a second voltage. It is preferred that the signal transfer component (120) is an electrical isolated component that can be an optocoupler or a relay, where two isolated electrical circuits are utilised to conduct the transmission of signals from one voltage to another. In addition, the electrical isolated component prevents the transfer of direct current (DC) and alternating current (AC) between the two electrical circuits while still allowing the transfer of the instruction signal. When the instruction signal that is powered at the first voltage and first form flows through the first electrical circuit, it activates the electromagnet of a relay or light of an optocoupler which then switches on the second electrical circuit of which the instruction signal flows therethrough at a second voltage and in the first form. The signal transfer component (120) provides isolation to protect the component connected to it, which is a control unit (130) from being damaged. Further, the signal transfer component (120) detects change in signal level from the thermostat (200) and provides notification regarding the signal level change to the control unit (130).

A control unit (130), preferably being a microcontroller, is disposed within the communication circuit and connected to the signal transfer component (120). The control unit (130) is employed for converting the instruction signal of the second voltage from the first form to a second form. In a preferred embodiment of the invention, the control unit (100) has five input pins connected to the output of the signal transfer component (120). These pins correspond to each operation mode and are used to detect the incoming instruction signal in the first form, which can be analogue form, from the signal transfer component (120) in order to enable the control unit (130) to acknowledge the operation request of the thermostat (200). When the control unit (130) acknowledges the requested operation, it will encode the instruction signal according to the communication protocol recognized by the thermostatically controlled system (300). Once the encoding process is completed, the output signal being the instruction signal in the second form, which can be digital form, is sent to the thermostatically controlled system (300) through a transferring (Tx) wire (421). The control unit (130) is also connected to the thermostatically controlled system (300) through a receiving (Rx) wire (422) that is used for the control unit (130) to receive operating information of the thermostatically controlled system (300). The operating information are used by the control unit (130) to manage the operation control data. In the example of HVAC system being the thermostatically controlled system (300), the instruction signal corresponding to an operation mode that operates at a first voltage, first current type and first form, is sent to the device (100) through a signal wire (410). Since the thermostat (200) is supplied with a power at the first voltage being 24 volts and first current type being alternating current, the instruction signal also operates at 24 volts alternating current (24 VAC). The first form of the instruction signal is analog. The instruction signal then passes to the signal transfer component (120) which transfers the instruction signal from a first voltage to a second voltage. The first electrical circuit of the signal transfer component (120) is powered at the first voltage which is 24 volts and the first current type being alternating current.

On the other hand, the device (100) is powered at the second voltage being 5 volts and second current type being direct current. Although the device (100) can be powered by an external power source, in this preferred embodiment of the invention, the device (100) receives power supply from the thermostatically controlled system (300). Therefore, the voltage of the device (100) has to be similar or lower than the thermostatically controlled system (300) and the current type is the same as the thermostatically controlled system (300). Since the device (100) is powered at 5 volts, the second electrical circuit and the control unit (300) are also operated at the same voltage. When the instruction signal is transferred to the second circuit of the signal transfer component (120), voltage of the instruction signal is transferred from the first voltage of 24 volts to the second voltage of 5 volts. At the same time, the transfer of alternating current from the first circuit is prevented from being transferred to the second circuit that is powered by direct current. The instruction signal is operated at the second current type of direct current.

When the instruction signal of 5 volts direct current (VDC) reaches the control unit (130) as an input signal, the control unit (130) responds with an output signal which is defined as an instruction signal of 5 volts in digital form if the requested operation communicated by the input signal corresponds to an available operation mode of the HVAC system. The instruction signal in digital form from the control unit (130) is a recognisable command by the HVAC system. For example, if the operation mode selected by a user is the cooling mode (Yl), the HVAC system adjusts its operation mode to cool the area at which the HVAC system is installed upon receiving the recognisable command.

Although the description above contains many specifications, it is understood that the embodiments of the preferred form are not to be regarded as a departure from the invention and it may be modified within the scope of the appended claims.