Abstract:
A test equipment arrangement includes a superheat controller configured for connection to a unit under test, and further configured to test at least one operational parameter of the unit under test.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 62/219,841, filed Sep. 17, 2015, the disclosure of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention relates in general to test equipment arrangements. In particular, this invention relates to an improved end of line test equipment arrangement having a superheat controller that is configured to replace certain components used in a conventional end of line test equipment arrangement. 
         [0003]    U.S. Pat. No. 9,140,613 discloses a superheat controller (SHC). The SHC disclosed therein is a single, self-contained, stand-alone device which contains all the sensors, electronics, and processing capability to automatically detect a fluid type, such as refrigerant, and report the superheat of multiple common fluid types used in residential, industrial, and scientific applications. U.S. Pat. No. 9,140,613 is incorporated herein in its entirety. 
         [0004]      FIGS. 3 and 4  herein illustrate a known SHC  10 , which is similar to the superheat controller disclosed in U.S. Pat. No. 9,140,613. As shown in  FIGS. 3 and 4 , the illustrated embodiment of the SHC  10  includes a housing  12  having a body  14 , a cover  16 , and a fluid inlet member  18 . The fluid inlet member  18  may be secured to the housing  12  by a mounting ring  19 . The mounting ring  19  attaches the fluid inlet member  18  to the housing  12  portion by a threaded connection. Alternatively, the mounting ring  19  may be attached to the fluid inlet member  18  by any desired method, such as by welding or press fitting. In the embodiment illustrated in  FIGS. 3 and 4 , the fluid inlet member  18  is a brass fitting having a centrally formed opening that defines a sealing surface  20 . When used in a known manner in a conventional heating, ventilating, air conditioning, and refrigeration (HVAC-R) system (not shown), the sealing surface  20  of the SHC  10  may engage a connector in the HVAC-R system to define a metal-to-metal seal. 
         [0005]    Known superheat controllers include a pressure sensor as an integral component thereof. For example, the known SHC  10  includes an integrated pressure and temperature sensor  22  having pressure sensor portion  24  and a temperature sensor portion  26  mounted to a printed circuit board (PCB)  28 . A superheat processor  30 , a data-reporting or communication module  32 , and an Input/Output (TO) module  34  are also mounted to the PCB  28 . The IO module  34  is a physical hardware interface that accepts input power and reports data through available hard-wired interfaces, such as wires or cables  36 , to the superheat processor  30 . Target devices that may be connected to the SHC  10  via the IO module  34  are schematically illustrated at  38  in  FIG. 4  and may include additional temperature sensors, laptop and notebook computers, cell phones, memory cards, and other devices. Alternatively, the target devices  38  may be connected to the communication module  32  by a wireless connection. 
         [0006]    The superheat processor  30  is mounted to the PCB  28  and is a high-resolution, high accuracy device that processes the input signals from the pressure and temperature sensor portions  24  and  26 , respectively, of the integrated pressure and temperature sensor  22 , detects the fluid type, calculates the superheat of the fluid, and provides an output that identifies the level of the calculated superheat. The superheat processor  30  may also be configured to provide other data, such as fluid temperature, fluid pressure, fluid type, relevant historical dates maintained in an onboard memory (such as alarm and on-off history), and other desired information. Advantageously, the superheat processor  30  maintains a high level of accuracy over a typical operating range of pressure and temperature after a one-time calibration. Non-limiting examples of suitable superheat processors include microcontrollers, Field Programmable Gate Arrays (FPGAs), and Application Specific Integrated Circuits (ASICs) with embedded and/or off-board memory and peripherals. 
         [0007]    Conventional end of line test equipment arrangements may be used to test devices such as microvalves, microvalve enabled devices, other electronic fluid valves, and other electronic devices such as pressure sensors and flow sensors after the devices have been manufactured and/or assembled. The conventional end of line test equipment arrangement may include a test stand with one or more of the following test components configured to test at least one operational parameter of a device or unit under test (UUT): a multimeter (to identify and measure input voltage to the UUT), a thermistor, a pressure transducer (to measure input pressure to the device), a pulse width modulation (PWM) driver (to control power to the device), a pressure regulator, a pressure reducer, one or more power sources of electrical power, a computer, and a data acquisition device. 
         [0008]    There remains, however, a need in the art for a simplified end of line test equipment arrangement that has fewer test components and is therefore easier to construct and is more efficient. 
       SUMMARY OF THE INVENTION 
       [0009]    The present application describes various embodiments of an improved test equipment arrangement wherein certain test components used in the test equipment arrangement are replaced with a superheat controller. 
         [0010]    In one embodiment, a test equipment arrangement includes a superheat controller configured for connection to a unit under test, and further configured to test at least one operational parameter of the unit under test. 
         [0011]    In another embodiment, the test equipment arrangement includes a test component configured for connection to a unit under test, and further configured to test at least one operational parameter of the unit under test. A superheat controller is configured for connection to the unit under test, and also configured to test at least one operational parameter of the unit under test not tested by the test component. The superheat controller includes a processer configured to perform at least one of the functions of a multimeter, a pulse width modulation driver, and a pressure transducer. 
         [0012]    In an additional embodiment, a method of testing an electronic device includes connecting a superheat controller to the electronic device, wherein the superheat controller is configured to test at least one operational parameter of the electronic device. The at least one operational parameter of the electronic device is then tested with the superheat controller. 
         [0013]    Various advantages of the invention will become apparent to those skilled in the art from the following detailed description, when read in view of the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a block diagram illustrating a first embodiment of an improved end of line test equipment arrangement according to this invention. 
           [0015]      FIG. 2  is a block diagram illustrating a second embodiment of an improved end of line test equipment arrangement according to this invention. 
           [0016]      FIG. 3  is a perspective view of a known universal superheat controller. 
           [0017]      FIG. 4  is a cross sectional view of the known universal superheat controller illustrated in  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0018]    Referring now to  FIG. 1 , a first embodiment of an improved test equipment arrangement according to the invention is shown generally at  40 . 
         [0019]    The test equipment arrangement  40  may be an end of line test equipment arrangement and thus configured to test devices, such as a unit under test (UUT)  46 , after the UUT  46  has been manufactured and/or assembled. Alternatively, the test equipment arrangement  40  may be configured to test a UUT  46  at any stage of its manufacture and/or assembly. The improved test equipment arrangement  40  includes a pressure regulator  42 , a pressure sensor or transducer  44 , and a unit under test (UUT)  46  located between the pressure regulator  42  and the pressure transducer  44 . The pressure transducer  44  measures input pressure to the UUT  46 . Pressure data from the pressure transducer  44  may be routed through a data acquisition device  50 , a processor, such as a computer  52 , and a converter module  54  connected to the SHC  10 . A pressure reducer  48  may be connected to the pressure transducer  44 . 
         [0020]    The pressure reducer  48  may be any desired pressure reducer, including a conventional pressure reducer configured to delay pressurized gas moving through the UUT  46  from going to ambient air pressure. The pressure transducer  44  may be any desired pressure transducer, such as a Viatran model 247 pressure transducer, or any pressure transducer configured to convert pressure into an electrical signal. The converter module  54  may be any desired converter module, such as a U485G converter module, or any converter module configured to facilitate communication conversion from USB to RS485 or RS422 data protocols. 
         [0021]    The computer  52  may have a USB hub  53  attached thereto for connecting one or more SHCs  10  within the test equipment arrangement  40 . The SHC  10  may be further connected to the UUT  46 . The SHC  10 , as well as any of the other test components of the test equipment arrangement  40 , may be powered by a power supply  56 . In the illustrated embodiment, pressurized gas, such as nitrogen or air from a source of pressurized gas  58 , may be introduced to the UUT  46  through the pressure regulator  42  in a known manner. The pressurized gas travels from the pressure regulator  42 , in the direction of the arrows A, through the UUT  46 , the pressure transducer  44 , the pressure reducer  48 , and may be vented into the environment E in which the test equipment arrangement  40  is located. 
         [0022]    As used herein, the following terms and phrases are defined as indicated: 
         [0023]    1. “Unit Under Test” (UUT): a device that needs power to be actuated or to perform a desired task. The UUT  46  may include devices such as modular silicon expansion valves (MSEVs), other microvalve enabled devices, microvalves, other electronic fluid valves, and other electronic devices such as pressure sensors and flow sensors. 
         [0024]    2. “Modular Silicon Expansion Valve” (MSEV): an electronically controlled, normally closed, and single flow directional refrigerant expansion valve. The MSEV may be used for refrigerant mass flow control in heating, ventilating, and air conditioning and refrigeration (HVAC-R) applications. The MSEV provides precise superheat control and includes a microvalve embedded therein. One example of a suitable MSEV is the MSEV manufactured by DunAn Microstaq, Inc. of Austin, Tex. 
         [0025]    3. “Pulse Width Modulation” (PWM): a modulation technique used to encode a message into a pulsing signal. PWM is typically used to allow the control of the power supplied to electrical devices. 
         [0026]    4. PWM driver: a device that controls the power to the UUT. An average value of voltage and current fed to the UUT may be controlled by turning the power from a source of power to the electrical device on and off at a fast rate. For power delivery, PWM may be used to control the amount of power delivered to a load, such as the UUT, without incurring the losses that would result from linear power delivery by resistive means. In addition to power delivery, the PWM driver may be useful in many other applications, including the control of servo-mechanisms, telecommunications signal modulation, voltage regulation, and for audio effects and amplification. 
         [0027]    5. “Superheat Controller” (SHC): a device that contains all the sensors, electronics, and processing capability required to automatically detect multiple fluid types, such as refrigerants, with minimal need for re-calibration, and report the superheat of the multiple common fluid types used in residential, industrial, and scientific applications. One example of such a superheat controller is disclosed in U.S. Pat. No. 9,140,613. The SHC  10  disclosed herein may be configured to provide additional data, such as fluid temperature, fluid pressure, fluid type, historical dates maintained in an onboard memory (such as alarm and on-off history), and other desired information. The SHC  10  may also be configured as a high-resolution processor that is able to detect and process resistance and voltage information and control the output of electricity from a source of electrical power, such as a power supply, to the UUT  46 , and is able to detect and control input PWM and output pressure. 
         [0028]    6. “Thermistor”: a type of resistor having a resistance that varies significantly with temperature, and/or has a resistance that varies more than standard resistors. 
         [0029]    7. “Data Acquisition Device”: a device that converts analog waveforms into digital values for processing by the SHC  10 . 
         [0030]    8. “Converter Module”: a module or device that performs communication conversion between USB computer ports and conventional RS485 and RS422 data networks. One non-limiting example of a suitable converter module is a U485G converter module. 
         [0031]    The pressure transducer  44  may be configured to sense and measure gas and/or fluid pressure in the UUT  46 . For example, the pressure transducer  44  may generate a signal, typically an electrical signal, as a function of the pressure imposed thereon. The pressure transducer  44  may be further configured to sense and measure input and/or output pressure of the UUT  46 . In addition to sensing and measuring input and/or output pressure of the UUT  46 , the pressure transducer  44  may be useful in many applications, such as to indirectly measure variables including fluid or gas flow, flow speed, fluid level, and altitude. 
         [0032]    In addition to the functions of the superheat processor disclosed in U.S. Pat. No. 9,140,613, the superheat processor  30  within the SHC  10  may be configured as a high-resolution processor that is able detect and process resistance and voltage information and control the output of electricity from a source of electrical power, such as the power supply  56 , to the UUT  46 . 
         [0033]    The various test and other components of the test equipment arrangement  40  may be mounted or positioned on a stand, schematically illustrated at  59 , and may be configured to test a plurality of UUTs  46 , such as MSEVs. 
         [0034]    In the illustrated embodiment of the test equipment arrangement  40  shown in  FIG. 1 , the SHC  10  is advantageously configured to perform a PWM function and further configured to protect the UUT  46  from overvoltage. This capability of the SHC  10  thus allows the test equipment arrangement  40  to be assembled without a conventional PWM driver to control power to the UUT  46 , and without a conventional multimeter to read input voltage to the UUT  46 . This saves space, as both the conventional PWM driver and the conventional multimeter are significantly larger than the SHC  10 . 
         [0035]    In the illustrated embodiment for example, the superheat processor  20  within the SHC  10  may be configured to protect the UUT  46  by detecting electrical resistance at the UUT  46  before supplying power to the UUT  46 , thus obviating the need for a conventional multimeter. In lieu of a conventional multimeter, the superheat processor  20  within the SHC  10  may be provided with an algorithm to sense the input voltage supplied to the UUT  46  within the test equipment arrangement  40 , and further to quickly shut off power to the UUT  46  before the UUT  46  is damaged if an over-voltage condition is sensed, thus obviating the need for both the conventional PWM driver and the conventional multimeter. 
         [0036]    The SHC  10  may also perform a very large number of PWM cycles on the UUT  46  and, thus, rigorously test the UUT  46  for wear and tear. For example, the SHC  10  may execute one million or more PWM cycles on the UUT  46 . 
         [0037]    Various physical test reference points may be assigned within the test equipment arrangement  40 . In the embodiment of the test equipment arrangement  40  shown in  FIG. 1 , three test points are shown at TP 1 , TP 2 , and TP 3 . For example, test point TP 1  may be used to confirm whether a desired voltage, such as 5 V, has been routed to the pressure transducer  44 . Test point TP 2  may be used to confirm whether a desired voltage, such a 12 V or 24 V, has been routed to the SHC  10 . Test point TP 3  may be used to confirm that the desired PWM signal in being sent to the UUT  46 . It will be understood that the test equipment arrangement  40  may be configured with any desired of test points configured to check or confirm the function of any test component of the test equipment arrangement  40 . 
         [0038]    Referring now to  FIG. 2 , a second embodiment of an improved equipment arrangement according to the invention is shown generally at  60 . Like the test equipment arrangement  40 , the test equipment arrangement  60  may be an end of line test equipment arrangement and thus configured to test devices, such as a UUT  46 , after the UUT  46  has been manufactured and/or assembled. Alternatively, the test equipment arrangement  60  may be configured to test a UUT  46  at any stage of its manufacture and/or assembly. 
         [0039]    The illustrated improved test equipment arrangement  60  may be configured to test a plurality of the UUTs  46 . Although two UUTs  46  are shown in  FIG. 2 , the line test equipment arrangement  60  may be configured to test any desired number of UUTs  46 . 
         [0040]    The improved test equipment arrangement  60  includes the pressure regulator  42  connected to each of two SHCs  64 . Valves  68  are connected between each SHC  64  and the UUTs  46 . The valves  68  control the flow of gas (i.e., turn the supply of gas on and off) to the UUTs  46 . The valves  68  may be any desired type of valve, such as a solenoid valve. The SHCs  64  may be structurally identical to the SHC  10  illustrated in  FIG. 1 , but are advantageously configured to perform the functions of a conventional PWM driver, a conventional multimeter, and the pressure transducer  44 . Like the test equipment arrangement  40 , the UUTs  46  in the test equipment arrangement  60  are provided with pressurized gas, such as nitrogen or air that may be introduced to the UUTs  46  from the source of pressurized gas  58  and through the pressure regulator  42  in a known manner. The SHCs  64 , as well as any of the test or other components of the test equipment arrangement  60 , may be powered by one or more sources of electrical power, such as the power supply  56  (not shown in  FIG. 2 , but shown in  FIG. 1 ). The various test components of the test equipment arrangement  60  may be mounted or positioned on a stand (not shown). 
         [0041]    If desired, a data acquisition device, such as the data acquisition device  50 , may be provided to communicate or provide an interface between the solenoid valves  68  and the computer  52 . 
         [0042]    In the embodiment illustrated in  FIG. 2 , each SHC  64  may be advantageously configured to perform a PWM driver function, act as a pressure transducer, and further configured to protect the UUTs  46  from overvoltage in the same manner as a conventional multimeter. This capability of the SHC  64  thus allows the test equipment arrangement  60  to be assembled without a conventional PWM driver, without a pressure transducer  44 , and without a conventional multimeter. 
         [0043]    As described above, a single SHC, including the SHCs  10  and  64 , may replace one or more of the typical test components of a conventional end of line test equipment arrangement, such as the PWM driver, the multimeter, and the pressure transducer  44 . Additionally, the SHCs  10  and  64  may be configured to perform the functions of other conventional end of line test equipment arrangement test components, such as a thermistor and any other desired test components. Thus, the use of the SHC  10  and the SHC  64  in lieu of any one or more of these end of line test equipment arrangement test components allows the improved end of line test equipment arrangements  40  and  60  to be simpler by reducing the number of test components used therein, and thereby reducing the size of the improved end of line test equipment arrangements  40  and  60 . Further, the cost and the maintenance requirements of the improved end of line test equipment arrangements  40  and  60  relative to a conventional end of line test equipment arrangement may be reduced. 
         [0044]    In  FIGS. 1 and 2 , the SHCs  10  and  64  are shown attached within the improved end of line test equipment arrangements  40  and  60 , respectively. It will be understood however, that the SHCs  10  and  64  may be configured to: perform a PWM driver function, act as a pressure transducer, protect devices such as the UUTs  46  from overvoltage, or perform any combination of these functions, and may be used with any device upon which a PWM driver function, pressure sensing and measurement, and/or input voltage detection is desired. Such devices may include the MSEVs, described above, other microvalve enabled devices, microvalves, electronic fluid valves, and other electronic devices such as pressure sensors and flow sensors. 
         [0045]    The principle and mode of operation of the invention have been described in its preferred embodiments. However, it should be noted that the invention described herein may be practiced otherwise than as specifically illustrated and described without departing from its scope.