The present disclosure relates generally to the field of remote sensors and controllers. More specifically, the present disclosure relates to systems and methods for using one or more wireless sensors in conjunction with a host controller such as an HVAC controller.
Remote sensors are utilized in a variety of applications for measuring parameters such as air temperature, relative humidity, carbon monoxide levels, and motion occurring within a home or other building. In HVAC systems, such remote sensors may be used to sense the air temperature at various locations within the building. For example, many hotel rooms have a remote sensor wall unit. The remote sensor wall unit typically has a temperature sensor to sense the temperature in the hotel room. A HVAC controller, typically located remote from the remote sensor wall unit, typically receives signals from the remote sensor wall unit and controls a fan coil unit, a roof top unit, a damper, or other HVAC component accordingly. Likewise, remote sensors are often employed to permit an HVAC controller to sense and control the temperature in multiple zones within a home or other building.
The connection of a remote sensor to an HVAC controller often requires the installation of wires between the remote sensor(s) and the HVAC controller. This can increase the cost of installation, and in many cases such as in some retrofit applications, may not even be practical. While the use of wireless sensors has gained in popularity, such systems typically require that the HVAC controller itself include a wireless transceiver for receiving the wireless signals from the wireless remote sensors. The HVAC controller then processes the received wireless signals to read the sensed parameter value therefrom. This can increase the cost of many systems, especially in retrofit situations.
The present disclosure relates to systems and methods for using one or more wireless sensors in conjunction with a controller such as an HVAC controller that has one or more remote sensor input(s). A remote sensor input, which can include one or more separate terminals, may be configured to be connected to a wired remote sensor having certain predetermined sensor characteristics. For example, a remote sensor input of an HVAC controller may be configured to be wired to a 10K ohm thermistor, a 20K ohm thermistor, a 30K ohm thermistor, or some other sensor having an expected impedance or impedance range. Alternatively, or in addition, a remote sensor input may be configured to be wired to an analog current signal (e.g. 4-20 mA), an analog voltage signal, or a signal having a certain frequency characteristic or the like provided by a wired remote sensor.
A wireless sensor with a wireless transmitter may be provided for sensing one or more environmental parameters remote from an HVAC controller. A decoder, with a wireless receiver, may be connected to a remote sensor input of an HVAC controller. During use, the wireless sensor may transmit a wireless signal that encodes or otherwise represents the sensed environmental parameter(s). The decoder may receive the wireless signal transmitted by the wireless sensor. The decoder may then convert the received wireless signal into a signal that is compatible with the expected sensor characteristics of the corresponding remote sensor input of the HVAC controller. From the point of the view of the HVAC controller, the wireless sensor and decoder may collectively provide a signal that mimics an output of expected wired remote sensor, and may present data to the HVAC controller as if the data had come directly from a wired remote sensor.
It is contemplated that in some cases, the decoder may have selectable output characteristics so that the wireless sensor and decoder can be used in conjunction with a variety of remote sensor inputs. For example, the output of the decoder may be selectable to provide a signal that mimics a 10K ohm thermistor, a 20K ohm thermistor, a 30K ohm thermistor, or some other expected impedance or impedance range of a wired remote sensor. Alternatively, or in addition, the output of the decoder may be selectable to provide a signal that mimics an analog current signal (e.g. 4-20 mA), an analog voltage signal, or a signal having a certain frequency characteristic or the like of a wired remote sensor. In some cases, the wireless sensor and decoder can be used to provide a wireless sensor solution for many convention HVAC controllers that have a remote sensor input that is conventionally wired to a remote sensor.
The following description should be read with reference to the drawings, in which like elements in different drawings are numbered in like fashion. The drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the disclosure. Although several examples are illustrated in the various views, those skilled in the art will recognize that many of the examples provided have suitable alternatives that can be utilized. Moreover, while the various devices, systems and methods herein are generally described for use in HVAC systems, it should be understood that the present invention can be employed in other applications involving the connection of wireless sensors to controllers. Such applications may include, but are not limited to, industrial, manufacturing and other applications, as desired.
Referring now to
In some cases, a user interface 22 can be included to provide signals to and from the HVAC controller 10. The user interface 22 can include a number of buttons, a touch screen, an LCD panel and keypad, a computer (e.g. a PDA), and/or any other suitable device for sending and receiving information to and from the controller 10. In certain embodiments, the user interface 22 may include a menu-driven interface that allows the user to navigate through one or more menus or screens to view and, if desired, modify various operational settings and parameters of the HVAC controller 10.
In some cases, the HVAC controller 10 may have an internal sensor 24 located within the controller housing for sensing the temperature and/or humidity levels at the location of the controller 10, but this is not required. The inclusion of such an internal sensor 24 is optional. When provided, the internal sensor 24 may include, for example, a thermistor, thermocouple, or any other suitable sensor or sensor type for locally sensing temperature at or near the HVAC controller 10. Other types of internal sensors such as humidity sensors, carbon monoxide sensors, carbon dioxide sensors, fire sensors, motion sensors, and/or occupancy sensors may be provided, depending on the type of controller 10.
Many conventional HVAC controllers are equipped with one or more remote sensor inputs, each of which may include one or more terminals. Conventionally, and during use of such HVAC controllers, a remote sensor 28 may be wired to each or selected ones of the remote sensor inputs of the HVAC controller 10. Typically, the remote sensors 28 will present a current, resistance, voltage, frequency and/or other sensor characteristics to the processor 12 via I/O interface 18. The particular current, resistance, voltage, frequency and/or other sensor characteristic may represents a sensed parameter, such as the ambient air temperature or other sensed parameter at or near the remote location of the remote sensor 28. The connection of such wired remote sensors 28 typically require the installation of wires extending between the wired remote sensor(s) 28 and the HVAC controller 10. This can increase the cost of installation, and in many cases, may not even be practical such as in some retrofit applications.
In the illustrative embodiment, the wireless sensor 32 includes a sensor 36 adapted to sense or measure one or more environmental parameters. The sensor 36 can be configured to output a sensor output signal 37 to a processor 38 or other circuit, which then converts or encodes the sensor output signal 37 into a wireless signal 40 for transmission to the decoder 34 via a wireless transmitter 42. In some cases, the wireless transmitter 42 may be a wireless transceiver and may be capable of both transmitting and receiving signals to/from the decoder 34. Example signals that might be sent to the wireless sensor 32 may include, but are not limited to, battery status requests, wakeup from sleep state requests, go to sleep state requests, calibration information, acknowledge messages, and/or any other suitable signal, request or message, depending on the application.
In some cases, the processor 38 of the wireless sensor 32 can include, for example, an A/D converter that converts an analog sensor output signal 37 into a digital signal 40. In other embodiments, the sensor 36 may be connected to a circuit that replaces or supplements the processor 38, and which converts or helps convert the signal 37 into a digital or other form. In some embodiments, the processor 38 and/or circuit may produce an output that has a frequency that is representative of the sensed parameter.
The signal 40 output by the processor 38 (and/or other circuit) can be fed to a wireless transmitter 42 having an antenna 44. In some cases, and as noted above, the transmitter 42 may be part of a transceiver. The wireless transmitter may transmit a wireless signal 46, such as an RF signal. The wireless signal 46 can then be received by the decoder 34. In some embodiments, the transmitter 42 can be configured to transmit an RF signal 46 using a radio communications protocol such as BLUETOOTH (i.e. IEEE 802.15.1 standard), ZIGBEE (IEEE 802.15.4 standard), WiFi (i.e. IEEE 802.11 standard), a proprietary communications protocol, or any other suitable protocol, as desired. The wireless signal 46 may contain other data in addition to the sensed parameter information, such as channel identification information uniquely identifying the wireless sensor 32, power status information indicating the power status of the wireless sensor 32, and or any other suitable information, as desired.
Other climate control information such as temperature setpoints may also be transmitted as part of the wireless signal 46. In some embodiments, for example, the wireless sensor 32 may be equipped with a keypad and LCD display allowing the user to adjust the temperature remotely using the wireless sensor 32. The temperature setpoints selected by the user may be transmitted along with the sensed parameter information and/or channel identification information to the decoder 34, if desired.
The decoder 34 can include a receiver 48 and antenna 50 adapted to receive the wireless signals 46 transmitted by the wireless sensor 32. In some cases, the receiver 48 of the decoder 34 may be part of a transceiver, and may be capable of also transmitting signals to the wireless sensor 32. Example signals that might be transmitted to the wireless sensor 32 may include, but are not limited to, battery status requests, wakeup from sleep state requests, go to sleep state requests, calibration information, acknowledge messages, and/or any other suitable signal, request or message, depending on the application.
When both the wireless sensor 32 and the decoder 34 include a transceiver, the wireless sensor 32 and decoder 34 can be configured to communicate in a bi-directional manner, allowing information to be transmitted between the decoder 34 to the wireless sensor 32. For example, the decoder 34 may be configured to transmit signals back to the wireless sensor 32 indicating whether the controller 10 is currently in a heating mode or cooling mode as well as the temperature setpoint for that mode. In some cases, this signal can then be viewed by the user at the wireless sensor 32 and used to adjust the temperature setpoint for the current mode, if desired. The adjustment made by the user can then be transmitted back to the decoder 34, and passed onto the controller 10.
A processor 54 (and/or other suitable circuit) within the decoder 34 can be configured to receive signal 52 from the receiver 48 of the decoder 34, and convert the signals 52 into an appropriate signal that is compatible with the expected sensor characteristics of a corresponding remote sensor input of the I/O interface 18 of the controller 10. When so provided, and from the point of the view of the controller 10, the wireless sensor 32 and decoder 34 may collectively mimic an expected wired remote sensor, and may present data to the HVAC controller 10 as if the data had come directly from a conventional wired remote sensor. In some cases, the CPU 54 of the decoder 34 may include a D/A converter. The D/A converter may produce an analog output signal 56 that mimics the output of a conventional wires sensor at the sensed value. This output signal 56 can then be fed to the I/O interface 18 of the controller 10.
It is contemplated that in some cases, the decoder 34 may have selectable output characteristics so that the wireless sensor 32 and decoder 34 can be used in conjunction with a variety of remote sensor input types of various controllers 10. For example, the output 56 of the decoder 34 may be selectable to mimics either a 10K ohm thermistor, a 20K ohm thermistor, a 30K ohm thermistor, or some other expected impedance or impedance range. Alternatively, or in addition, the output 56 of the decoder 34 may be selectable to mimic an analog current signal (e.g. 4-20 mA), an analog voltage signal, or a signal having a certain frequency characteristic or the like that might be expected by the particular remote sensor input of the controller 10. In some cases, the wireless sensor 32 and decoder 34 can be used to provide a wireless sensor solution for a convention HVAC controller that has a remote sensor input that is designed to be wired to a conventional wired remote sensor.
Although the various components of the illustrative wireless device 32 including the sensor 36, processor 38, and transmitter (or transceiver) 42 can be contained within a single device, as depicted generally by the dashed lines in
During operation, the thermistor 36 can output an analog current, resistance or voltage signal 37 based on the particular temperature coefficient of the thermistor 36. For example, and in some cases, the processor 38 or some other circuit of the wireless sensor 32 may provide a known current to the thermistor 36, and the resulting voltage across the thermistor 36 may be provided as analog voltage signal 37 that is representative of the sensed temperature. Alternatively, the processor 38 or some other circuit of the wireless sensor 32 may provide a known voltage to the thermistor 36, and the resulting current through the thermistor 36 may be provided as analog current signal 37 representative of the sensed temperature. In either case, the processor 38 may converts the analog signal 37 into a signal 40 that is representative of the sensed temperature value, and the transmitter (or transceiver) 42 may wirelessly transmit a corresponding wireless signal 46 to the receiver (or transceiver) 48 of the decoder 34.
The wireless signal 46 received by the receiver (or transceiver) 48 of the decoder 34 can be converted to a signal 52, which is fed to the processor 54 of the decoder 34. The processor 54 may be programmed to provide an analog signal 56, or may present a resistance, to the I/O interface 18 of the controller 10 that replicates or mimics the analog signal 37 or resistance produced by, for example, the thermistor 36 or some other thermistor that might normally be wired to a remote sensor input of the I/O interface 18 of the controller 10. In some embodiments, for example, the processor 54 can be configured to convert the signal 52 into an analog format that mimics or replicates a 10 kΩ thermistor, assuming the remote sensor input of the I/O interface 18 of the controller 10 is configured to expect a 10 kΩ thermistor.
It is contemplated that in some cases, the decoder 34 may have selectable output characteristics so that the wireless sensor 32 and decoder 34 can be used in conjunction with a variety of remote sensor input types. For example, the format of output 56 of the decoder 34 may be selectable to mimics a 10K ohm thermistor, a 20K ohm thermistor, a 30K ohm thermistor, or some other expected impedance or impedance range. Alternatively, or in addition, the format of output 56 of the decoder 34 may be selectable to mimic an analog current signal (e.g. 4-20 mA), an analog voltage signal, or a signal having a certain frequency characteristic or the like that might be expected by the particular remote sensor input of the I/O interface 18 of the controller 10.
The wireless sensor 32 can be configured to output a signal in response to an event such as the detection of motion, which can then be converted by the processor 38, and transmitted by the transmitter (or transceiver) 42 to the receiver (or transceiver) 48 of the decoder 34. The decoder 34 can then pass the received signal onto the processor 54, which may convert the signals 52 into an output signal 56 that is compatible with a remote sensor input of the controller 10. In some embodiments, for example, the processor 54 can be configured to output an analog signal 56 to the controller 10 that mimics or replicates an analog signal that might normally be produced by a wired remote occupancy sensor. For example, the processor 54 can be configured to output a 4-20 mA signal to the controller 10 depending on whether motion is detected by the wireless sensor 32. Alternatively, and in other embodiments, the processor 54 can be configured to output a digital signal to the controller 10 (e.g. active high or low) that can be used in conjunction with, or in lieu of, a digital signal that might normally be fed to the controller 10 from a wired-in occupancy sensor.
Other types of remote sensors 36 may be connected to the controller 10 in a similar manner for sensing other types of parameters, if desired. Examples of other types of remote sensors 36 may include, but are not limited to, humidity sensors, carbon monoxide sensors, fire sensors, carbon dioxide sensors, radon detectors, pressure sensors, light detectors, door sensors, proximity sensors, window sensors, switches, and/or motion sensing devices such as accelerometers or gyroscopes.
Although the illustrative systems in
For example, a decoder 34a in communication with a wireless temperature sensor 32a may be configured to output an analog signal 56a that replicates the output from a wired thermistor that might normally be wired to a corresponding remote sensor input of controller 10. The second decoder 34b, in turn, may be configured to output a high or low current signal 56b to a corresponding remote sensor input of controller 10, based on whether motion is detected by a remote occupancy or motion sensor 32b. Any interference between the wireless signals 46a,46b transmitted by each wireless device 32a,32b can be reduced or eliminated by sending the signals 46a,46b at discrete time intervals and/or by assigning different frequencies or bands to each wireless device 32a,32b. In some cases, identification of each wireless device 32a,32b can be accomplished by, for example, the assignment of a unique identification code by each processor 38, which can be sent along with the sensed information to the corresponding decoder 34a,34b.
Although each wireless device 32a,32b is shown in
In one illustrative embodiment, once connected, the decoder can be configured to poll each wireless sensor for a wireless signal, as indicated generally at block 68. At startup, the wireless sensor can be configured to send a few initially sensed parameters to the decoder, as indicated generally at block 70. In those embodiments where the wireless sensor is a temperature sensor, the sensor can be configured to provide an initial number of temperature measurements signals for a predetermined period of time (e.g. every 10 seconds for 5 minutes). If no such signal is available, the decoder can provide the controller with the last sensed parameter transmitted by the temperature sensor, or if no such signal is available, a pre-programmed value stored within the decoder. If desired, the decoder can be configured to offset or otherwise calibrate the temperature measurements received from the temperature sensor by a desired amount to account for any differences in temperature between the location of the wireless temperature sensor and the HVAC controller and/or to account for any other calibration factors. Alternatively, or in addition, such an offset or calibration may be applied by the HVAC controller, if desired.
The wireless signals received from each wireless sensor can be converted into a signal by the decoder that mimics or replicates a signal that would normally be provided by a wired remote sensor to the remote sensor input of the HVAC controller, as indicated generally at block 72. The conversion of the wireless signal can be accomplished by, for example, using a look-up table, a conversion map, an equation, a discrete circuit, and/or any other suitable method to produce a signal response that mimics the response that would normally be provided by a wired remote sensor.
The output signal provided by the decoder can be used by the HVAC controller in lieu of the signal that would normally be provided by a wired remote sensor, as indicated generally at block 74. Since the decoder output signal mimics the temperature or other signals normally provided by a wired remote sensor, the user may be allowed to connect the wireless sensor to the controller without having to reconfigure the existing wiring scheme or to reprogram the controller to accept the new wireless remote sensor.
In some cases, once an initial number of signals have been received by the decoder and have been converted for use by the controller, the wireless sensor can be configured to revert to a second mode of operation whereby wireless signals are provided to the decoder only in response to a change sensed by the wireless sensor, as indicated generally at blocks 76 and 78. When a wireless temperature sensor is employed, for example, the wireless sensor can be configured to transmit a temperature measurement signal to the decoder only in response to a sensed temperature change that is greater than 0.125° F., 0.25° F., 0.5° F., or some other threshold amount. The transmission of signals to the decoder only upon a sensed change in temperature may help reduce transmitter energy usage, which can prolong battery life when a battery is the power source, and may reduce interference with other wireless devices operating in the same general area. If the sensed temperature does not vary by the threshold amount within a predefined time period (e.g. 30 minutes), the transmission from the wireless temperature sensor can occur irrespective of any sensed temperature difference to provide confirmation to the controller that the sensor is still functioning properly. As indicated generally by block 80, the HVAC controller may control one or more HVAC system components based at least in part on the signals received from the decoder.
Having thus described several embodiments, those of skill in the art will readily appreciate that other embodiments may be made and used which fall within the scope of the claims attached hereto. It will be understood that this disclosure is, in many respects, only illustrative. Changes can be made with respect to various elements described herein without exceeding the scope of the invention.