Line Voltage Interface for Automation Systems

Abstract

An integrated PCB-based solid state line voltage interface for use in automated control system applications. Relays connect various functional loads to the line level source in response to input from a controller unit. Switches enable a user to override the controller unit, and manually control the connection of the functional loads. An alternative embodiment of the present invention further includes limit switches. The compact nature of the device facilitates ease of installation, mounting of multiple units in the same space, and mounting in various specialized locations as desired.

Description

TECHNICAL FIELD

The present invention relates to the field of automation. More specifically, the present invention relates to the field of automation systems. More specifically, the invention relates to interfacing between automated control units, power sources, and two-speed or reversing electrical motors.

BACKGROUND ART

Automation systems employ controller devices such as microprocessors, computers, and programmable logic controllers (PLC's), to control machinery, equipment, and processes.

These systems may control various equipment including fans, dampers, valves, vents, shade, and other equipment. Typically, automated controller units are used to read a set of digital and/or analog inputs, apply a set of logic statements, and then generate a set of low voltage (50 volt or less) analog and/or digital output signals. These output signals are transferred from the automated control system to either additional low voltage interface relays or pilot relays, that are then operative of the final power relays. The power relays finally engage the relevant line voltage loads, or electrical motors. These existing low voltage pilot relays or interface devices may or may not have integral override switches, but are not capable of transferring the full motor load.

Automation interfacing of reversing or two-speed motors also requires additional relays, wiring, and override switches which are usually custom built from individual electrical components. The sheer volume of components required often necessitates that large or multiple electrical boxes be utilized. Such a bulky arrangement is not conducive to mounting in tight or compact spaces. Additionally, in some situations it may be desirable to locate the reversing motor interface so as to facilitate the electrical installations (e.g. locating the interface next to the controller versus next to motor). The complicated and non-compact manner in which present art relay/switch systems are built for automation interfacing inhibits one's ability to locate the components and wiring in the most cost-effective, compact, and desirable configuration.

Therefore, there is a need for an integrated device for automation interfacing of reversing or 2-speed motor applications. Such an integrated device would incorporate relays and switches in a single, compact, easily installed interface. Such a device would facilitate automatic control of the line voltage load by a controller unit, as well as enabling manual override and control for special situations.

DISCLOSURE OF THE INVENTION

The present invention is drawn to an integrated solid state line voltage interface for use in automated control system applications. The interface is situated between a controller, a power source, and a load. It is composed of a printed circuit board having relays, switches, and indicator lights mounted thereto. The relays connect various functional loads to the power source in response to input from a controller unit. The switches enable a user to override the controller unit, and manually control the connection of the functional loads. In various embodiments of the invention, the switches are directly interposed between the load and the source, bypassing any relays, and thus facilitating direct control of the actual connection between the load and the source. An alternative embodiment of the present invention includes limit switches, which are useful in preventing excessive travel in applications having defined directional limits (e.g. windows, shades, etc). An alternative embodiment of the invention further includes a time delay which delays the connection of the load. This is useful in applications involving a reversing motor to allow the motor time to wind down before changing direction.

The compact nature of the present invention offers significant advantages over prior art methods of installation. The compact device presently disclosed integrates required components, is simpler to install, facilitates mounting of multiple units in the same space, and is more easily mounted in various locations as desired.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a circuit diagram of a line voltage interface in accordance with an embodiment of the present invention.

FIG. 2 is a circuit diagram of a line voltage interface in accordance with an alternative embodiment of the present invention.

FIG. 3 is a circuit diagram of a line voltage interface in accordance with an alternative embodiment of the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION

The present invention is drawn to an integrated solid state line voltage interface for use in automated control applications. The present invention replaces separate relays and switches and their associated wiring by combining these components into a compact integrated device that is easy to install.

FIG. 1 illustrates a circuit diagram of a line voltage interface 100 for interfacing between an automated controller unit, a power source, and a two-speed motor, in accordance with an embodiment of the present invention. Interface 100 receives Function A and Function B signals at terminals 10 and 15 from a controller unit (not shown). These signals correspond to the low speed and high speed of a two-speed motor (not shown), which may effect such operations as the cooling stages of a climate controlled building. The relays are circuited such that both Function A relay 20 and Function B relay 25 have their normally closed poles connected, and fed line voltage. The common poles of both Function A relay 20 and Function B relay 25 are connected. The normally open pole of Function A relay is circuited to Function A motor load terminal 30; the normally open pole of Function B relay 25 is circuited to Function B motor load terminal 35. When no signal is present, the Function A relay 20 and Function B relay 25 are normally closed, thus preventing either load circuit from being made. When a Function A signal is received at terminal 10 (with no Function B signal present), indicator 17 (e.g. an LED) turns on, and the Function A relay 20 is energized, thereby changing from a normally closed to normally open state. This connects the Function A load at terminal 30 to the source. Likewise, when a Function B signal is received at terminal 15 (with no Function A signal present), indicator 18 turns on, and the Function B relay 25 is energized and changes to the open state, thus connecting the Function B load at terminal 35 to the source. In the event that the interface 100 receives simultaneous signals for Function A and Function B, then both relays 20 and 25 are energized and change to the open state, which causes the Function A and B loads to connect to each other. The result is that neither load connects to the source, which prevents damage that might otherwise occur as a result of receiving simultaneous and conflicting signals.

Switch 40 affects the controlling input for the interface 100. When switch 40 is in the auto position, the connection of the Function A and B loads to the source is determined by the controller unit (not shown) as described above. When switch 40 is in the off position, no connection of the loads is possible. When switch 40 is in the manual position, then the connection of the loads is determined by the position of switch 45, Switch 45 has positions for connecting the Function A and B loads, as well as an off position. Together, switches 40 and 45 enable a user to override the controller unit and manually control the connection of the loads to the source. Because switches 40 and 45 are directly interposed between the loads and the source, this configuration allows a user to directly switch the actual functional load, and is especially useful in the event the controller unit becomes inoperative.

The circuit of interface 100 as disclosed may be embodied in a printed circuit board having the aforementioned solid state components mounted thereto. In this manner, interface 100 is constructed to be a single unit that may be easily installed in a desirable manlier.

The interface 100 of the invention has been described with reference to a two-speed motor, such that Function A and Function B loads correspond to the two speeds of a two-speed motor. However, it is recognized that the Function A and Function B loads may correspond to alternatives such as forward and reverse directions of a reversing motor.

FIG. 2 illustrates a circuit diagram of a line voltage interface 200 for interfacing between an automated controller unit, a power source, and a two-speed motor, in accordance with an alternative embodiment of the present invention. Interface 200 receives Function A and Function B signals at terminals 110 and 115 from a controller unit (not shown). These signals correspond to the two speeds of a two-speed motor (not shown). The relays are circuited so that the common pole of Function B relay 125 is fed line voltage. The normally closed pole of Function B relay 125 is connected to the common pole of Function A relay 120. The normally open pole of Function A relay is circuited to Function A motor load terminal 130; the normally open pole of Function B relay 125 is circuited to Function B motor load terminal 135. When no signal is present, the Function A relay 20 and Function B relay 25 are normally closed. When a Function A signal is received at terminal 110 (with no Function B signal present), indicator 117 turns on, and the Function A relay 120 is energized and changes from a closed to open state. This connects the Function A load at terminal 30 to the source. Likewise, when a Function B signal is received at terminal 115 (with no Function B signal present), indicator 118 turns on, and the Function B relay 125 is energized and changes to the open state, thus connecting the Function B load at terminal 135 to the switched source. In the event that the interface 200 receives signals for both Function A and Function B, then both relays 120 and 125 will change to the open state, which results in connection of the Function B load to the source, while the Function A load is not connected. This arrangement is useful in particular applications where the Function A and Function B signals are staged or sequentially supplied and maintained by the controller unit, as it maintains Function B when receiving simultaneous signals for both Function A and B. Thus, the interface 200 is especially applicable to mechanisms such as multi-speed fans, and stepped cooling and heating mechanisms.

Switch 140 affects the controlling input for the interface 200. When switch 140 is in the auto position, the connection of the Function A and B loads to the source is determined by the controller unit (not shown) as described above. When switch 140 is in the off position, no connection of the loads is possible. When switch 140 is in the manual position, then the connection of the loads is determined by the position of switch 145. Switch 145 has positions for connecting the Function A and B loads, as well as an off position. Switches 140 and 145 are directly interposed between the loads and the source, thereby allowing a user to directly switch the actual functional loads.

The interface 200 of the invention has been described with reference to a two-speed motor, such that Function A and Function B loads correspond to the two speeds of a two-speed motor. However, it is recognized that the Function A and Function B loads may correspond to alternatives such as forward and reverse directions of a reversing motor.

FIG. 3 illustrates a circuit diagram of a line voltage interface 300 for interfacing between an automated controller unit, a power source, and a reversing motor, in accordance with an alternative embodiment of the present invention. Interface 300 receives open and close signals at terminals 210 and 215 from a controller unit (not shown). These signals correspond to the forward and reverse directions of a reversing motor (not shown). The relays are circuited such that both Close relay 225 and Open relay 220 have their normally closed poles connected, and fed line voltage. The common poles of both Open relay 220 and Close relay 225 are connected together. The normally open pole of Open relay 220 is circuited to the Open motor load terminal 230; the normally open pole of Close relay 225 is circuited to the Close motor load terminal 235. When an open signal is received at terminal 210, the open relay 220 is energized and changes from a closed to open state. This connects the open load at terminal 230 to the source. Likewise, when a close signal is received at terminal 215, close relay 225 is energized and changes to the open state, thus connecting the close load at terminal 235 to the line source. In the event that the interface 300 receives simultaneous signals for open and close, then both relays 220 and 225 are energized and change to the open state, which causes the open and close loads to connect to each other. The result is that neither load connects to the source.

Time delays 240 and 245 delay the energization of relays 220 and 225, respectively. This feature is particularly useful when the Function A and B loads are the forward and reverse directions of a reversing electrical motor. The delays prevent immediate changes from one direction to the other, allowing time for the motor to wind down. This prevents damage to the motor that could result from immediate changes in direction.

Limit switches (not shown), as are known in the art, are connected to terminals 260, and function to limit the activation of relays 220 and 225. This is useful for limiting the range of operation of the loads, and may prevent damage that would otherwise result from exceeding the range of operation.

Switch 250 affects the controlling input for the interface 300. When switch 250 is in the auto position, the connection of the relays 220 and 225 are fed by the controller unit (not shown) as described above. When switch 250 is in the off position, the relays cannot be energized. When switch 250 is in the manual position, then the energization of the relays is determined by the position of switch 255. Switch 255 has positions for energizing each of the relays, as well as an off position.

Interface 300 as illustrated in FIG. 3 is shown as having 24V power supplied to operate the coils of the relays and to operate the time delay and limit switches. The loads are shown as connecting to either 24V or 120V AC power (120V AC being conventional line level voltage in the United States). The voltages shown are conventional in the art, and are merely representative of a possible configuration for the interface. It is recognized that other voltages may be applied, this being contemplated within the scope of the present invention.

The aforementioned embodiments of the invention each may be constructed by mounting the relevant solid state components to a printed circuit board having a circuit design as disclosed. By combining these several components into a single integrated device, the required amount of wiring is reduced, and ease of installation is greatly improved. Because the device is compact, several units may be easily mounted in a single electrical box, which is in contrast to conventional methods that entail mounting separate components in multiple electrical boxes. The installation of multiple units in a single space also facilitates easy and simultaneous access to multiple interfaces.

Furthermore, the compact nature of the device of the present invention means that it is easily mounted in various locations for convenience, aesthetics, cost-efficient use of materials, or as otherwise desirable. For example, it may be desirable to locate the interface in close proximity to the line level load (e.g. a reversing motor) in order to facilitate intuitive and direct control when needed. The integrated device of the present invention can be easily mounted in such a location while occupying a minimum of space.

Information as herein shown and described in detail is fully capable of attaining the above-described object of the invention, and is, thus, representative of the subject matter which is broadly contemplated by the present invention. The scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and is to be limited, accordingly, by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.”

All structural and functional equivalents to and combinations of the elements of the above-described preferred embodiment and additional embodiments that are known to those of ordinary skill in the art are hereby expressly incorporated by reference and are intended to be encompassed by the present claims. However, it should be readily apparent to those of ordinary skill in the art that various changes and modifications in form, apparatus material, and fabrication material detail may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

Moreover, no requirement exists for a device or method to address each and every problem sought to be resolved by the present invention, for such to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim herein is to be construed under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is expressly recited using the phrase “means for.”

INDUSTRIAL APPLICABILITY

The present invention is industrially applicable to automated control systems.

Claims

1. An interface for interfacing between an automated controller unit, a power source, and a reversing motor, said interface having at least one relay and at least one switch, said relay connecting said motor to said power source, and said switch facilitating manual override of said relay.

2. An interface as in claim 1, wherein said interface comprises a printed circuit board for coupling solid state components.

3. An interface as in claim 2, further including a second switch for controlling speed and direction of said motor.

4. An interface as in claim 3, wherein said second switch controls power directly applied to said reversing motor.