Self-verification of the controller's internal circuits

Abstract

Systems and methods for testing circuit operation are provided. Aspects include a circuit comprising a power supply, a switching element, and a load. A sensing element is disposed between the switching element and the load, and the sensing element is communicatively coupled to a microcontroller, wherein the microcontroller is configured to perform diagnostic operations for the circuit, the diagnostic operations comprising: in response to operating the switching element, obtaining first sensor data associated with the load from the sensing element, wherein the first sensor data comprises an electrical value associated with the load; obtaining second sensor data associated with an output of the switching element from the sensing element, wherein the second sensor data comprises an electrical value associated with the output of the switching element; and analyzing the first sensor data and the second sensor data to determine a fault condition of the circuit.

Description

Background Art

[0001] The exemplary embodiments relate to the field of circuit diagnostics and, more particularly, to self-verification of circuits within a container controller.

[0002] A transport refrigeration unit (TRU) is a container designed to carry perishable goods at a specific temperature or within a temperature range. A TRU can be equipped with a variety of refrigeration systems for maintaining a specific temperature within the cabinet. Typically, a control system operates the refrigeration system to maintain the temperature within the cabinet. These control systems are composed of circuit elements that can fail over time. In addition, connections between components of the control system can degrade or become disconnected. For example, a load on a control system can lose mechanical connection to a pin of the control system. There is a need for a testing process for various locations within the circuits used for the control system to identify the cause of a failure, rather than simply replacing the control system when there is a failure. Summary of the invention

[0003] According to one embodiment, a system is provided. The system includes a circuit, the circuit including a power supply, a switching element, and a load. A sensing element is arranged between the switching element and the load, and the sensing element is communicatively coupled to a microcontroller, wherein the microcontroller is configured to perform a diagnostic operation for the circuit, the diagnostic operation including: in response to operating the switching element, obtaining first sensor data associated with the load from the sensing element, wherein the first sensor data includes an electrical value associated with the load; obtaining second sensor data associated with an output of the switching element from the sensing element, wherein the second sensor data includes an electrical value associated with the output of the switching element; and analyzing the first sensor data and the second sensor data to determine a fault condition of the circuit.

[0004] In addition to or as an alternative to one or more of the above features, other embodiments of the system may include analyzing the first sensor data includes comparing an electrical value associated with the load to an operating range of values ​​for the load.

[0005] In addition to or as an alternative to one or more of the above features, other embodiments of the system may include analyzing the second sensor data includes comparing an electrical value associated with the output of the switching element to an operating range of values ​​for the output of the switching element.

[0006] In addition to one or more of the above features, or as an alternative, other embodiments of the system may include: diagnostic operations for the circuit further include associating a fault condition with a load based on the following determinations: a determination that an electrical value associated with the load is outside an operating range of values ​​for the load; and a determination that an electrical value associated with the output of the switching element is within an operating range of values ​​for the output of the switching element.

[0007] In addition to one or more of the above features, or as an alternative, other embodiments of the system may include: the sensing element is a first sensing element; and wherein the system further includes a second sensing element arranged between the power supply and the sensing element, the second sensing element being communicatively coupled to the microcontroller, wherein diagnostic operations for the circuit further include: obtaining third sensor data associated with the power supply from the second sensing element, wherein the third sensor data includes an electrical value associated with the power supply; and comparing the electrical value associated with the power supply with an operating range of values ​​for the power supply.

[0008] In addition to one or more of the above features, or as an alternative, other embodiments of the system may include: diagnostic operations for the circuit further include associating a fault condition with a switching element based on the following determinations: a determination that an electrical value associated with the output of the switching element is outside an operating range of values ​​for the output of the switching element; and a determination that an electrical value associated with the power supply is within an operating range of values ​​for the power supply.

[0009] In addition to or as an alternative to one or more of the above features, other embodiments of the system may include: diagnostic operations for the circuit further include associating a fault condition with the power supply based on a determination that an electrical value associated with the power supply is outside an operating range of values ​​for the power supply.

[0010] In addition to or as an alternative to one or more of the above features, other embodiments of the system may include that the diagnostic operations for the circuit further include generating an alarm based on the fault condition, and displaying the alarm on the display device.

[0011] In addition to or as an alternative to one or more of the above features, other embodiments of the system may include: the sensing element comprising a voltage sensing circuit.

[0012] In addition to or as an alternative to one or more of the above features, other embodiments of the system may include: the sensing element comprising a current sensing circuit.

[0013] In addition to or as an alternative to one or more of the above features, other embodiments of the system may include: the sensing element comprising a feedback resistor coupled to the output of the switching element.

[0014] In addition to or as an alternative to one or more of the above features, other embodiments of the system may include an analog-to-digital converter communicatively coupled to the microcontroller.

[0015] In addition to or as an alternative to one or more of the above features, other embodiments of the system may include: the circuit is a control system for a trailer refrigeration unit.

[0016] According to one embodiment, a method is provided. The method includes: obtaining, by a processor, first sensor data associated with a load on the circuit from a sensing element in the circuit, wherein the circuit includes a power supply and a switching element, wherein the first sensor data is obtained in response to operation of the switching element, wherein the first sensor data includes an electrical value associated with the load; obtaining second sensor data associated with an output of the switching element from the sensing element, wherein the second sensor data includes an electrical value associated with the output of the switching element; and analyzing the first sensor data and the second sensor data to determine a fault condition of the circuit.

[0017] In addition to one or more of the above features, or as an alternative, other embodiments of the method may include: analyzing the first sensor data includes comparing the electrical value associated with the load and the operating range of the value for the load, and analyzing the second sensor data includes comparing the electrical value associated with the output of the switching element and the operating range of the value for the output of the switching element.

[0018] In addition to one or more of the above features, or as an alternative, other embodiments of the method may include associating a fault condition with a load based on: a determination that an electrical value associated with the load is outside an operating range of values ​​for the load; and a determination that an electrical value associated with the output of the switching element is within an operating range of values ​​for the output of the switching element.

[0019] In addition to one or more of the above features, or as an alternative, other embodiments of the method may include: obtaining third sensor data associated with the power supply from a second sensing element in the circuit, wherein the third sensor data includes an electrical value associated with the power supply; and comparing the electrical value associated with the power supply to an operating range of values ​​for the power supply.

[0020] In addition to one or more of the above features, or as an alternative, other embodiments of the method may include associating a fault condition with a switching element based on the following determinations: a determination that an electrical value associated with the output of the switching element is outside an operating range of values ​​for the output of the switching element; and a determination that an electrical value associated with the power supply is within an operating range of values ​​for the power supply.

[0021] In addition to or as an alternative to one or more of the above features, other embodiments of the method may include associating a fault condition with the power supply based on a determination that an electrical value associated with the power supply is outside an operating range of values ​​for the power supply.

[0022] In addition to or as an alternative to one or more of the above features, other embodiments of the method may include: generating an alert based on the fault condition; and displaying the alert on a display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The following description should not be considered limiting in any way. Referring to the drawings, similar elements are similarly numbered:

[0024] Figure 1 depicts a transport refrigeration unit in an exemplary embodiment;

[0025] Figure 2 A schematic diagram of an embodiment of a refrigeration unit is depicted;

[0026] Figure 3 depicts a block diagram of a control system with self-verification utilizing internal circuitry according to one or more embodiments; and

[0027] Figure 4 A flow chart of a method for testing circuit operation is depicted in accordance with one or more embodiments. DETAILED DESCRIPTION

[0028] Turning now to an overview of the technology more specifically related to aspects of the present disclosure, a transport refrigeration unit (TRU) is a container designed to carry perishable goods at a specific temperature or within a certain temperature range. A refrigerated freight truck or refrigerated tractor trailer, such as one used to transport goods by sea, rail or road, is a truck, trailer or cargo container that generally defines a cargo compartment and is modified to include a refrigeration system at one end of the truck, trailer or cargo container. The refrigeration system typically includes a compressor, a condenser, an expansion valve and an evaporator, which are connected in series in a closed refrigerant circuit through refrigerant lines according to the well-known refrigerant vapor compression cycle. A power unit such as an internal combustion engine drives the compressor of the refrigeration unit and can be a diesel-powered, natural gas-powered or other type of engine. The TRU can be equipped with a variety of refrigeration systems for maintaining a specific temperature within the cabinet. Typically, an onboard controller circuit manages the operation of the refrigeration system. Over time, the onboard controller circuit needs to be maintained and / or tested. To check the functional operation of the controller's outputs, the output status is manually monitored by trained service personnel who will activate the outputs and monitor the load conditions and output operation through a voltmeter or ammeter tested at various test points. These service test points allow service technicians to troubleshoot system failures for the controller circuits. Since controllers typically have multiple outputs, this manual testing can be complex. For example, current refrigeration controllers have 29 outputs. To meet cost and space constraints on these controller circuits, these service test points can be eliminated.

[0029] Turning now to an overview of aspects of the present disclosure, one or more embodiments of the present disclosure solve the above-mentioned problems by providing a system and method for allowing a controller to perform self-verification using internal current and voltage sensing inputs. The controller can perform self-verification using three internal sensors that monitor the controller output. The controller output can contain a mix of loads on the controller, such as, for example, a 24V A / C load and a 12V D / C load. Internal voltage feedback from the power input and at each output being monitored can be compared with the expected voltage change at the output due to the output change of state. The internal current sensor reading of the measured current consumption can be compared with the expected current consumption for 12V DC and 24V AC loads. Monitoring of the output voltage and current consumption allows self-diagnosis of the correct output operation to be performed on the controller.

[0030] As mentioned above, a controller (or control system) is utilized in the TRU. Figure 1 An example transport refrigeration system 50 with a refrigerated trailer is depicted. The trailer can be pulled by a tractor 52. The exemplary trailer includes a container 54 defining an internal cabin 56. It is to be understood that the embodiments described herein can be applied to shipping containers that are transported by rail or sea without using a tractor 52. An equipment housing 58 mounted to the front of the container 54 can contain a power source. The refrigeration system can be electrically coupled to the power source to receive power. As is well known in the art, the refrigeration system includes a compressor, a condenser, an expansion valve, and one or more evaporators that define a refrigeration circuit for circulating refrigerant. The refrigeration system also includes one or more fans, such as a condenser fan, an evaporator fan, or a ventilation fan. It is to be understood that the embodiments described herein can be applied to shipping containers or any other suitable containers that are transported by rail, sea, or air, whereby the vehicle can be a truck, a train, a ship, an airplane, etc.

[0031] Figure 2 Refrigeration system 60 is shown in a schematic diagram of an embodiment of a refrigeration system 60. Refrigeration system 60 includes a power source 96, a refrigeration unit 64 having a compressor 76, a condenser 78, a refrigerant regulator 70, an evaporator 82, and fans 74, 84, and a control system 86 ("controller"). Refrigeration unit 64 is configured so that refrigerant passes through compressor 76, condenser 78, refrigerant regulator 70, and evaporator 82 in a closed loop path 88. Fan 84 has an alternating current ("ac") motor or a direct current ("dc") motor and is configured to regulate the refrigerant from the evaporator 82 through the evaporator 82. Figure 1 The interior compartment 56 and / or in some embodiments from Figure 1 The air 80 outside the interior compartment 56 is returned to the Figure 1The fan 74 has an alternating current ("ac") motor or a direct current ("dc") motor and is configured to move air 90 through the condenser 78 to the exterior to remove heat from the refrigeration system. The power supply 96 is adapted to supply power to one or more of the components of the refrigeration unit 64 (e.g., the compressor 76, the refrigerant regulator 70, the fan 84, the fan 74, the processor 98, etc.).

[0032] The controller 86 includes a processor 98 adapted to receive one or more feedback signals indicative of environmental parameters (e.g., temperature, pressure, humidity, etc.) in the interior cabin and / or the refrigeration unit 64 from one or more sensors 40 located within the interior cabin and / or the refrigeration unit 64 and / or feedback signals indicative of operating parameters of the refrigeration unit 64. The processor 98 is further adapted to selectively maintain or change the operating mode of the refrigeration unit 64 using an actuator 92 (e.g., a switch, valve, relay, triac, FET, transistor, and other power switching device) in communication with the refrigeration unit 64 based on the feedback signals, an algorithm, or some combination thereof. For example, a temperature value sensed within the interior cabin may prompt the controller 86 to engage a non-operating refrigeration unit 64 to supply cooling air to the interior cabin, or it may prompt the controller 86 to disengage an operating refrigeration unit 64. Similarly, an operating parameter value associated with the refrigeration unit 64 may prompt the controller 86 to engage a dormant refrigeration unit 64, or to disengage an operating refrigeration unit 64. It should be noted that the functionality of the processor 98 may be implemented using hardware, software, firmware, or a combination thereof.

[0033] Figure 3 A block diagram of a control system with self-verification using internal circuitry is depicted according to one or more embodiments. The control system includes a processor 302 and an analog-to-digital converter (ADC) 304. The processor 302 is configured to operate one or more power switches 306a, 306b. The control system includes one or more power sources 310, 312 and one or more loads 350, 352. The loads 350, 352 can be, for example, Figure 2 Any of the elements in the refrigeration unit 64. The power sources 310, 312 can be alternating current (AC) power sources or direct current (DC) power sources. The power sources 310, 312 can be connected to the switching elements 306a, 306b, which are connected to the power source 310 (high-side power switching element) or to ground (low-side power switching element). In one or more embodiments, the control system can be used as follows Figure 2 Controller 86 of refrigeration unit 64 described in .

[0034] In one or more embodiments, the power input from the power supplies 310, 312 can be monitored by the ADC 304 so that the processor 302 can detect the presence or availability of load power. Using the input into the ADC 304, the resistor 322 and the resistor 324 can monitor the power supply 310, and the resistor 326 and the resistor 328 can monitor the power supply 312. The output of the ADC 304 can pass through a multiplexer (MUX) before being routed to the processor 302. The processor 302 can analyze the ADC 304 output to determine whether the monitored voltage or current is within the normal operating range for the circuit to determine whether there is a potential problem related to the control system. In one or more embodiments, the reference voltage (VREF1) can provide a DC offset for the AC power signal to ensure that the complete AC signal can be read by the ADC 304. The current sensor 320 is used to monitor the load current going to the power output. The current sensor 320 can be an AC or DC current sensor.

[0035] In one or more embodiments, the switching elements 306a, 306b are controlled by the processor 302, which can control each element individually or in coordination as needed for both normal operation of the control system or during diagnostic testing of the system. The output of the first switching element 306a can be fed back through a first feedback resistor 332, which is connected to the ADC 304 through an input channel. The output of the second switching element 306b can be fed back through a second feedback resistor 334 connected to the ADC 304. For any other switching elements, additional feedback resistors 336 can be used. In one or more embodiments, the summing junction can be biased to a reference voltage (VREF2) to allow monitoring of the AC signal without clipping. The output of the switching elements 306a, 306b can have a pull-up resistor 334 or a pull-down resistor 342 to ensure that the analog signal from the switching elements 306a, 306b in the disconnected (OFF) state follows the expected state by avoiding floating outputs or errors caused by potential leakage currents. In one or more embodiments, the feedback resistors 332, 334, 336 can be much larger than the loads 350, 352 so that the feedback does not add any significant load to the switching elements 306a, 306b. In addition, the resistance ratio of the feedback resistors 332, 334, 336 to the common voltage feedback node (e.g., summing resistor) 338 can be optimized for resolution or range. The common voltage feedback node 338 for all outputs is used to sense changes in the voltage representing changes in the output state of one or more outputs. The benefit of a single voltage feedback node 338 for all outputs is reduced size and complexity, allowing all outputs to be monitored by a minimum amount of components and ADC resources (1 ADC channel).

[0036] In one or more embodiments, the processor 302 can be used to perform diagnostic operations to identify fault conditions within the circuits of the control system. This is performed by monitoring voltage and current values ​​using the ADC 304. If a problem related to the control system is detected, the diagnostic operation can be automatically initiated, eliminating the need for manual troubleshooting by a technician. During the diagnostic operation, the processor 302 can access known operating ranges of values ​​for different loads 350, 352 and power supplies 310, 312 from memory. For example, the nominal current consumption of each load 350, 352 can be stored in a memory accessed by the processor 302.

[0037] In one or more embodiments, the processor 302 can verify that the power supply exists and is within the operating range of values ​​by reading the corresponding ADC304 channel of the monitoring power supply 310, 312. The processor 302 can operate the switching elements 306a, 306b to turn on one or more of the output loads 350, 352. The processor 302 can verify the change in the load current and / or load voltage, and compare these values ​​with the operating range for the specific load. If the change in the load current and / or load voltage is not the expected value, the processor 302 can then verify whether the switching element is changing the state. If the switching elements 306a, 306b operate within the expected range of values, and the load current / voltage is not within the expected range of values, the load 350 may be the cause of a problem related to the control system. Some example load problems include wires or pins that are not properly connected to the load from the controller, or there are faulty components of the load (e.g., a bad compressor in a refrigeration unit, etc.). If the load current / voltage value is within the expected range of values, but there is no voltage at the output of the switching elements 306a, 306b, the switching element may be the cause of a problem related to the control system. However, to confirm that the switching element is the possible cause of the problem, the processor 302 monitors the power supply to determine whether the power supplies 310, 312 have voltage values ​​within the expected range of values ​​for the power supplies. If the power supplies 310, 312 have voltage values ​​within the expected range, and the load has a voltage / current value within the expected range, then the switching elements 306a, 306b are the cause of the problem and will need to be replaced. For example, the control system typically controls the refrigeration system load by using a contactor that is rated for a higher current and / or voltage than the smaller power switching device on the refrigeration control board. For example, in a container system, the control system will turn on the 24V AC output (triac / relay), which in turn will supply energy to the high voltage contactor that connects 460V AC power to the compressor. The embodiment refers to a diagnostic in the control system that will measure the 24V AC voltage / current applied to the high voltage contactor coil from the internal relay / triac, but the 460V AC voltage or current across the contactor contacts is not directly monitored. There are separate operational external voltage and current step-down transformers that can be used to monitor the primary voltage and current signals.One or more embodiments herein relate to monitoring the operation of internal power control devices of a control system rather than external power devices.

[0038] In one or more embodiments, the processor 302 can generate an alarm based on monitoring the voltage / current values ​​for the power supply, the switching element, and the load. This alarm can be displayed on a display device connected to the control system and accessed by a technician. In some embodiments, the alarm can be transmitted to the device via a network for display to a user.

[0039] Figure 4 A flow chart of a method for testing circuit operation according to one or more embodiments is depicted. As shown in block 402, method 400 includes a processor obtaining first sensor data associated with a load on the circuit from a sensing element in the circuit, wherein the circuit includes a power supply and a switching element, wherein the first sensor data is obtained in response to operation of the switching element, wherein the first sensor data includes an electrical value associated with the load. At block 404, method 400 includes obtaining second sensor data associated with an output of the switching element from the sensing element, wherein the second sensor data includes an electrical value associated with the output of the switching element. And at block 406, method 400 includes comparing the first sensor data and the second sensor data to determine whether a fault condition exists in the circuit.

[0040] Additional processes may also be included. It should be understood that Figure 4 The processes depicted in the present disclosure are illustrative and other processes may be added or existing processes may be removed, modified, or rearranged without departing from the scope and spirit of the present disclosure.

[0041] A detailed description of one or more embodiments of the disclosed apparatus is presented herein by way of illustration and not limitation, with reference to the accompanying drawings.

[0042] The term "about" is intended to encompass the degree of error associated with the measurement of a particular quantity based on the equipment available at the time the application was filed. For example, "about" can encompass a range of ±8% or 5% or 2% of a given value.

[0043] The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the present disclosure. When used herein, unless the context clearly indicates otherwise, the singular forms "a / an", and "the" are also intended to include the plural forms. It will be further understood that the terms "comprise and / or comprising" when used in this specification specify the presence of stated features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or groups thereof.

[0044] Although the present disclosure has been described with reference to one or more exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and that equivalents may be substituted for its elements without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt specific circumstances or materials to the teachings of the present disclosure without departing from its essential scope. Therefore, the present disclosure is not intended to be limited to the specific embodiments disclosed as the best mode envisioned for carrying out the present disclosure, but the present disclosure will include all embodiments falling within the scope of the claims.

Claims

1. A system for testing circuit operation, the system comprising: A circuit comprising a power supply, a switching element and a load; an analog-to-digital converter communicatively coupled to a microcontroller, wherein the microcontroller is configured to perform diagnostic operations for the circuit, the diagnostic operations comprising: in response to operating the switching element to turn on the load, obtaining, from the analog-to-digital converter, first data from a first node between a first resistor connected to the switching element and the load and a second resistor connected to a first reference voltage, wherein the first data includes an electrical value associated with the load; obtaining, from the analog-to-digital converter, second data from a second node between a third resistor connected to the power supply and the switching element and a fourth resistor connected to a second reference voltage, wherein the second data includes an electrical value associated with an output of the switching element; and analyzing the first data and the second data to determine a fault condition of the circuit, wherein analyzing the first data comprises: comparing the electrical value associated with the load to an operating range of values ​​for the load, wherein analyzing the second data comprises comparing the electrical value associated with the output of the switching element to an operating range of values ​​for the output of the switching element, Wherein, the diagnostic operation for the circuit further comprises: associating the fault condition with the load based on the following determination: a determination that the electrical value associated with the load is outside the operating range of values ​​for the load; and A determination is made that the electrical value associated with the output of the switching element is within the operating range of values ​​for the output of the switching element.

2. The system according to claim 1, wherein: The analog-to-digital converter is a first sensing element; and wherein the system further comprises: a second sensing element disposed between the power source and the switching element, the second sensing element being communicatively coupled to the microcontroller, wherein the diagnostic operation for the circuit further comprises: obtaining, from the second sensing element, third data associated with the power source, wherein the third data comprises an electrical value associated with the power source; and The electrical value associated with the power supply is compared to an operating range of values ​​for the power supply.

3. The system according to claim 2, wherein: The diagnostic operation for the circuit further includes: The fault condition is associated with the switching element based on the following determination: a determination that the electrical value associated with an output of the switching element is outside of the operating range of values ​​for the output of the switching element; and A determination is made that the electrical value associated with the power source is within the operating range of values ​​for the power source.

4. The system according to claim 2, wherein: The diagnostic operation for the circuit further includes: The fault condition is associated with the power source based on a determination that the electrical value associated with the power source is outside of the operating range of values ​​for the power source.

5. The system according to claim 1, wherein: The diagnostic operation for the circuit further includes: generating an alarm based on the fault condition; and The alarm is displayed on a display device.

6. The system according to claim 2, wherein: The first sensing element includes a voltage sensing circuit.

7. The system according to claim 2, wherein: The second sensing element includes a current sensing circuit.

8. The system according to claim 2, wherein: The first sensing element includes a feedback resistor coupled to an output of the switching element.

9. The system according to claim 1, wherein: The circuit is a control system for a trailer refrigeration unit.

10. A method for testing circuit operation, the method comprising: obtaining, by a processor, first data from a first node from an analog-to-digital converter in the circuit in response to operating a switching element in the circuit to turn on a load, the first node being between a first resistor connected to the switching element and the load and a second resistor connected to a first reference voltage, wherein the circuit includes a power source, the load, and the switching element, and the first data includes an electrical value associated with the load; obtaining, from the analog-to-digital converter, second data from a second node between a third resistor connected to the power supply and the switching element and a fourth resistor connected to a second reference voltage, wherein the second data includes an electrical value associated with an output of the switching element; as well as analyzing the first data and the second data to determine a fault condition of the circuit, wherein analyzing the first data comprises comparing the electrical value associated with the load to an operating range of values ​​for the load, wherein analyzing the second data comprises comparing the electrical value associated with the output of the switching element to an operating range of values ​​for the output of the switching element, The method further comprises: associating the fault condition with the load based on the following determination: a determination that the electrical value associated with the load is outside the operating range of values ​​for the load; and A determination is made that the electrical value associated with the output of the switching element is within the operating range of values ​​for the output of the switching element.

11. The method according to claim 10, further comprising: obtaining third data associated with the power source from a sensing element in the circuit, wherein the third data includes an electrical value associated with the power source; as well as The electrical value associated with the power supply is compared to an operating range of values ​​for the power supply.

12. The method according to claim 11, further comprising: The fault condition is associated with the switching element based on the following determination: a determination that the electrical value associated with an output of the switching element is outside of the operating range of values ​​for the output of the switching element; and A determination is made that the electrical value associated with the power source is within the operating range of values ​​for the power source.

13. The method according to claim 11, further comprising: The fault condition is associated with the power source based on a determination that the electrical value associated with the power source is outside of the operating range of values ​​for the power source.

14. The method according to claim 10, further comprising: generating an alarm based on the fault condition; as well as The alarm is displayed on a display device.

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