Remote programmable resistor

Abstract

The utility model discloses a remote programmable resistor, which belongs to the technical field of electronic information and consists of a main control module, a resistor module, a relay module, a state acquisition module, a man-machine interface module, an RS485 module, an Ethernet module and a power supply module. The main control module controls the output resistance value of the resistance module through the relay module, calculates the actual output resistance value of the resistance module through the state acquisition module, realizes local setting and display of the resistance value through the man-machine interface module, and realizes two remote modification setting and reading of the resistance value through the RS485 module and the Ethernet module; the power supply module has power supply conversion and backup lithium battery management functions, and provides a direct current power supply for each module; the resistance range, precision and power of the same resistor can be flexibly changed according to requirements, the resistor has the functions of local and remote simultaneous monitoring and resistance change, the application scene is expanded, the utilization rate is improved, and the purchase cost is saved.

Description

Technical Field

[0001] This utility model relates to a design method for a remotely programmable resistor, belonging to the field of electronic information technology. Background Technology

[0002] Programmable resistors are electronic components that can dynamically change their resistance value to adapt to specific circuit requirements, making them highly useful in a variety of applications. As high-precision standard resistors, they are used for calibration and adjustment of precision instruments, sensor simulation, and circuit simulation; as circuit signal conditioning, they are used for signal adjustment and matching in communication equipment, volume and screen brightness adjustment in consumer electronics, and circuit adjustment and control in industrial automation equipment; as load devices, they are used in product testing such as power supply testing, battery testing, solar energy testing, electric vehicle testing, and industrial control system testing. Currently, commonly used programmable resistors include manually operated resistance boxes, slide wire rheostats, and switchable resistance matrices with communication capabilities. The disadvantages of these resistors are that their resistance range, accuracy, and power cannot be flexibly changed according to requirements; they lack simultaneous local and remote monitoring and control functions; or they require the purchase of multiple resistors with different configurations, resulting in high costs. Summary of the Invention

[0003] Purpose of the invention: In order to achieve flexible changes in resistance range, accuracy, and power on the same resistor according to requirements, and to enable simultaneous local and remote monitoring and modification of resistance values, thereby expanding the application scenarios of resistors, improving the utilization rate of resistors, and saving procurement costs, this utility model proposes the following design method for a remotely programmable resistor.

[0004] Technical solution: To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0005] A remotely programmable resistor comprises a main control module, a resistor module, a relay module, a status acquisition module, a human-machine interface module, an RS485 module, an Ethernet module, and a power supply module. The main control module controls the output resistance value of the resistor module via the relay module, calculates the actual output resistance value via the status acquisition module, and enables local modification and display of the resistance value via the human-machine interface module (LED display, LED indicators, and keyboard). The RS485 and Ethernet modules enable remote modification and retrieval of the resistance value. The RS485 interface uses the MODBUS protocol, and the Ethernet interface uses the MQTT protocol. The power supply module converts AC 220V AC power to the DC power required by each module via a switching power supply.

[0006] Specifically, the resistor is in the shape of a cube, with a resistance area, a human-machine interface area, and a resistance output interface on the top. One side has a power interface (POW), a serial interface (RS485), and an Ethernet interface (ETH).

[0007] Specifically, the resistor region has 16 resistor bars, which can be manually removed to replace the resistors installed inside. Each resistor bar contains a resistor, which can be replaced with a suitable resistor depending on the resistor's output resistance range, accuracy, and power. The output resistance value is composed of four digits from 0 to 9. The units digit is achieved by combining R11, R12, R13, and R14; the tens digit by combining R21, R22, R23, and R24; the hundreds digit by combining R31, R32, R33, and R34; and the thousands digit by combining R41, R42, R43, and R44. By replacing the resistors with different resistance values ​​on the resistor bars, the output resistance range can be changed, with resistance ratios of 0.01, 0.1, 1, 10, 100, and 1000. This flexible design expands the application range of the resistor.

[0008] Specifically, the human-machine interface area consists of three parts: the upper part is a 4-digit LED segment code number used to display the resistor output resistance value; the lower part on the left has 6 LED indicator lights used to indicate the current resistance value multiplier; the lower part on the right has a simple keypad, from top to bottom, with left shift (decrease) key, right shift (increase) key, and confirmation key, used to modify the resistance value and multiplier settings.

[0009] Specifically, the power module contains a lithium battery. When there is AC power input at the power interface POW, it charges the backup lithium battery. When there is no AC power input at the power interface POW, the backup lithium battery provides the required DC power to each module, thus meeting the needs of applications where AC power cannot be provided.

[0010] Specifically, the relay module uses a magnetic latching relay to ensure that the correct resistance value can still be output when the resistor loses external and internal power, and to reduce power consumption when the power supply is normal.

[0011] Specifically, the output port of the main control module MCU is connected to the input port of the relay driver chip, and the output port of the driver chip is connected to the coil of the relay. The normally closed contact of the relay is connected in parallel across the two ends of the resistors with the same serial number. The resistance values ​​of the four resistors for the ones, tens, hundreds, and thousands digits are configured by multiplying by a factor of 8 / 80 / 800 / 8000, 4 / 40 / 400 / 4000, 2 / 20 / 200 / 2000, and 1 / 10 / 100 / 1000. Controlling different relay actions can change the resistance value of each digit. Taking the ones digit as an example, when relays K11, K12, K13, and K14 are not activated, their corresponding normally closed contacts are closed, and the four resistors for the ones digit are short-circuited, with a resistance value of zero. When relay K14 is activated, its corresponding normally closed contact is opened, and the resistance value for the ones digit is R14, which is 1. The other resistance values ​​are analogous.

[0012] Specifically, the input port of the main control module MCU is connected to one end of a 10k resistor and one end of a normally open contact of a relay. The other end of the 10k resistor is connected to the system power supply VCC, and the other end of the normally open contact of the relay is connected to the system power supply GND, thus forming a status acquisition module to calculate the output resistance value of the resistor.

[0013] Specifically, the resistance rod consists of a cylindrical handle, a cylindrical positioning baffle, a conductive upper copper ring, a resistor upper connecting screw, a resistor, a conductive lower copper ring, and a resistor lower connecting screw; the wires at both ends of the resistor are connected to the conductive upper copper ring and the conductive lower copper ring respectively through the resistor upper connecting screw and the resistor lower connecting screw; the resistor is connected to the circuit network of the resistor through the conductive upper copper ring and the conductive lower copper ring.

[0014] Specifically, the main program flow of the main control module includes the following steps:

[0015] S11. Perform hardware initialization and system initialization;

[0016] S12. Collect the resistor control status through the status acquisition module to determine whether each resistor is short-circuited by the normally closed contact of the relay.

[0017] S13. Calculate the current output resistance value based on the resistance control status, and drive the LED segment code of the human-machine interface to display the resistance value;

[0018] S14. Determine whether the output resistor value has been modified via the human-machine interface. If not, proceed to the next step; otherwise, proceed to S17.

[0019] S15. Determine if the output resistor value has been modified via the remote communication interface. If yes, proceed to the next step; otherwise, proceed to S18. S16. Parse the communication message to obtain the new output resistor value.

[0020] S17. Calculate the control state of each relay based on the resistance value, and drive the relay to modify the output resistance value;

[0021] S18. Determine whether the output resistor value has been read from the remote communication interface. If yes, proceed to the next step; otherwise, proceed to S12.

[0022] S19. Read the output resistance value and organize the communication message according to the communication protocol of the remote communication interface, send it out through the remote communication interface, and then proceed to S12.

[0023] Specifically, the operation process of the human-machine interface module includes the following steps:

[0024] S21. Press the OK button. The leftmost segment code number will flash for 1 second, indicating that the number has been selected.

[0025] S22. Press the left / right arrow keys to switch to other segment codes or the range indicator light will flash, indicating that other numbers or ranges are selected;

[0026] S23. Determine if the flashing position is a number. If yes, proceed to the next step; otherwise, proceed to S26.

[0027] S24. Press the OK button. The flashing interval of the flashing number will change to 0.5 seconds, indicating that the number has entered the editable state.

[0028] S25. Press the left / right arrow keys to change the value of the flashing number;

[0029] S26. Press the confirmation key to complete the modification of the flashing numbers or range, and the flashing will stop;

[0030] S27. If the range has been modified in the previous steps, the resistance rod or the internal resistance of the resistance rod must be replaced manually to meet the range requirements.

[0031] Beneficial effects: This method addresses the shortcomings of current resistors, such as the inability to flexibly change the resistance range, accuracy, and power according to requirements, the lack of simultaneous local and remote monitoring and control functions, or the need to purchase multiple resistors with different configurations, resulting in high costs. It proposes a design method for remotely programmable resistors, which enables flexible changes in resistance range, accuracy, and power according to requirements on a single resistor, and provides functions such as simultaneous local and remote monitoring and resistance value modification. This expands the application scenarios of resistors, improves resistor utilization, and saves procurement costs. Attached Figure Description

[0032] Figure 1 shows the external layout of the resistor of this utility model.

[0033] Figure 2 is a hardware architecture diagram of the resistor of this utility model.

[0034] Figure 3 shows the resistor control principle diagram and control table of this utility model.

[0035] Figure 4 shows the schematic diagram and status table of the resistor control status acquisition of this utility model.

[0036] Figure 5 is a structural diagram of the resistor rod of this utility model.

[0037] Figure 6 shows the main program flow of the resistor of this utility model.

[0038] Figure 7 shows the operation flow for setting the resistance value using the human-machine interface of this utility model. Detailed Implementation

[0039] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0040] Figure 1 shows the external layout of this utility model. The front has a resistor area 1, a human-machine interface area 2, and a resistor output interface 3. The sides have a power interface (POW), a serial interface (RS485), and an Ethernet interface (ETH). Resistor area 1 has 16 resistor bars, which can be manually removed to replace the resistors installed inside. Human-machine interface area 2 consists of three parts: the upper part is a 4-digit LED segment code displaying the resistor output resistance value; the lower left part has 6 LED indicator lights indicating the current resistance value multiplier; and the lower right part has a simple keypad with, from top to bottom, a left shift (decrease) key, a right shift (increase) key, and an confirmation key for modifying the resistance value and multiplier.

[0041] Figure 2 shows the hardware architecture diagram of this utility model. The resistor consists of a main control module, a resistor module, a relay module, a status acquisition module, a human-machine interface module, an RS485 module, an Ethernet module, and a power supply module. The main control module controls the output resistance value of the resistor module through the relay module, calculates the actual output resistance value of the resistor module through the status acquisition module, realizes local modification and display of the resistance value through the human-machine interface module, and realizes remote modification and reading of the resistance value through the RS485 module and the Ethernet module. The power supply module converts AC220 AC power to DC power required by each module through a switching power supply, and has an internal rechargeable lithium battery as a backup power source.

[0042] Figure 3 shows the schematic diagram and control table of the resistance control principle of this utility model. As shown in box five in the figure, the output port of the main control module MCU is connected to the input port of the relay driver chip, and the output port of the driver chip is connected to the coil of the relay; the normally closed contact of the relay is connected in parallel across the resistors with the same serial number. The output resistance value of the resistor is composed of four digits from 0 to 9. As shown in box one of the diagram, the units digit resistance value is achieved by combining R11, R12, R13, and R14; the tens digit resistance value is achieved by combining R21, R22, R23, and R24; the hundreds digit resistance value is achieved by combining R31, R32, R33, and R34; and the thousands digit resistance value is achieved by combining R41, R42, R43, and R44. The four resistor values ​​for the units, tens, hundreds, and thousands digits are configured by multiplying by a factor of 8 / 80 / 800 / 8000, 4 / 40 / 400 / 4000, 2 / 20 / 200 / 2000, or 1 / 10 / 100 / 1000. Controlling different relay actions can change the resistance value for each digit. Taking the units digit as an example, relays K11, K12, K13, and K14... When none of the resistors operate, the corresponding normally closed contacts close, short-circuiting all four resistors in the units digit, resulting in a resistance value of zero. When relay K14 operates, the corresponding normally closed contact opens, and the resistance value in the units digit becomes R14, which is 1. The control methods for other resistance values ​​are shown in the table in the diagram. The control methods for the resistances in the tens, hundreds, and thousands digits are similar to those for the units digits.

[0043] like Figure 4 The diagram shows the principle and status table of the resistor control status acquisition of this utility model. The input port of the main control module (MCU) is connected to one end of a 10kΩ resistor and one end of a normally open relay contact. The other end of the 10kΩ resistor is connected to the system power supply VCC, and the other end of the normally open relay contact is connected to the system power supply GND, forming the resistor control status acquisition module used for calculating the resistor output resistance value. Taking the acquisition of the unit resistance value as an example, the table lists the resistance values ​​corresponding to different combinations of switch signals acquired by the MCU input port. The acquisition of the tens, hundreds, and thousands resistance values ​​is similar to the acquisition of the unit resistance value.

[0044] Figure 5 shows the structural diagram of the resistor rod of this utility model. The resistor rod consists of a cylindrical handle 11, a cylindrical positioning baffle 12, a conductive upper copper ring 13, a resistor upper connecting screw 14, a resistor 15, a conductive lower copper ring 16, and a resistor lower connecting screw 17. The wires at both ends of the resistor 15 are connected to the conductive upper copper ring 13 and the conductive lower copper ring 16 respectively through the resistor upper connecting screw 14 and the resistor lower connecting screw 17. The resistor 15 is connected to the circuit network of the resistor through the conductive upper copper ring 13 and the conductive lower copper ring 16.

[0045] like Figure 6 The diagram shows the main program flow for the resistor of this utility model. The main program flow for the main control module is as follows:

[0046] S11. Perform hardware initialization and system initialization.

[0047] S12. The status of the resistor control is acquired through the status acquisition module to determine whether each resistor is short-circuited by the normally closed contact of the relay.

[0048] S13. Calculate the current output resistance value based on the resistance control status, and drive the LED segment code of the human-machine interface to display the resistance value.

[0049] S14. Determine whether the output resistor value has been modified via the human-machine interface. If not, proceed to the next step; otherwise, proceed to S17.

[0050] S15. Determine whether the output resistor value has been modified via the remote communication interface. If yes, proceed to the next step; otherwise, proceed to S18.

[0051] S16. Parse the communication message to obtain the new output resistor value.

[0052] S17. Calculate the control state of each relay based on the resistance value, and drive the relay to modify the output resistance value.

[0053] S18. Determine whether the output resistor value has been received from the remote communication interface. If yes, proceed to the next step; otherwise, proceed to S12.

[0054] S19. Read the output resistance value and organize the communication message according to the communication protocol of the remote communication interface, send it out through the remote communication interface, and then proceed to S12.

[0055] Figure 7 shows the operation procedure for setting the resistance value using the human-machine interface of this utility model. The specific operation procedure is as follows:

[0056] S21. Press the OK button. The leftmost segment code number will flash for 1 second, indicating that the number has been selected.

[0057] S22. Press the left / right arrow keys to switch to other segment codes or the range indicator light will flash, indicating that other numbers or ranges are selected.

[0058] S23. Determine if the flashing position is a number. If yes, proceed to the next step; otherwise, proceed to S26.

[0059] S24. Press the confirmation button. The flashing interval of the flashing number will change to 0.5 seconds, indicating that the number has entered the editable state.

[0060] S25. Press the left / right arrow keys to change the value of the flashing number.

[0061] S26. Press the confirmation key to complete the modification of the flashing numbers or range, and the flashing will stop.

[0062] S27. If the range has been modified in the previous steps, the resistance rod or the internal resistance of the resistance rod must be replaced manually to meet the range requirements.

[0063] The present invention has been disclosed above with reference to preferred embodiments, but these are not intended to limit the present invention. Anyone skilled in the art can make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of protection of the claims of this application.

Claims

1. A remote programmable resistor, the resistor is composed of a master control module, a resistance module, a relay module, a state acquisition module, a man-machine interface module, an RS485 module, an Ethernet module, a power module; characterized in that: The main control module controls the resistance module output resistance value size through the relay module, calculates the actual output resistance value size of the resistance module through the state acquisition module, realizes the local modification setting and display of the resistance value through the man-machine interface module, that is, the LED display screen, the LED indicator light and the keyboard, realizes the remote modification and reading of the resistance value through the RS485 module and the Ethernet module; the power module converts the AC 220V power supply into the DC power required by each module through the switching power supply; the RS485 interface adopts the MODBUS protocol, and the Ethernet interface adopts the MQTT protocol.

2. A remotely programmable resistor according to claim 1, characterized in that: The resistor has a cuboid shape, and has a resistance area (1), a man-machine interface area (2), and a resistance output interface (3) on the top surface. One side surface has a power interface POW, a serial interface RS485, and an Ethernet interface ETH.

3. The remotely programmable resistor of claim 1, wherein: The resistance area (1) has 16 resistance rods, which can be manually pulled out to replace the resistance installed inside; each resistance rod has a resistance inside, which can be replaced with a resistance that meets the requirements according to different resistance output resistance ranges, different accuracies, and different powers; the resistor output resistance value is composed of four 0-9 digits, the unit resistance value is realized by R11, R12, R13, and R14, the ten resistance value is realized by R21, R22, R23, and R24, the hundred resistance value is realized by R31, R32, R33, and R34, and the thousand resistance value is realized by R41, R42, R43, and R44; by replacing the resistance with different resistance values on the resistance rod, the output resistance value range can be changed, and the resistance value ratio is 0.01, 0.1, 1, 10, 100, and 1000.

4. The remotely programmable resistor of claim 1, wherein: The man-machine interface area (2) is composed of three parts: the upper part is a 4-digit LED segment code number, used to display the resistor output resistance value; the lower part has six LED indicator lights on the left, used to indicate the current resistance value ratio; and the lower part has a simple keyboard on the right, from top to bottom, which is a left shift / reduction key, a right shift / increase key, and a confirmation key, used to modify and set the resistance value and the ratio.

5. The remotely programmable resistor of claim 1, wherein: The power module contains a lithium battery, and when there is an AC power input at the power interface POW, the backup lithium battery is charged, and when there is no AC power input at the power interface POW, the backup lithium battery provides the required DC power to each module, meeting the application in the application where AC power cannot be provided; in order to ensure that the resistor can still output the correct resistance value when it loses external and internal power supply, and to reduce power consumption when the power is normal, all relays are magnetic latching relays.

6. The remotely programmable resistor of claim 1, wherein: The output port of the master control module MCU is connected to the input port of the relay drive chip, the output port of the drive chip is connected to the coil of the relay; the normally closed contact of the relay is connected in parallel across the resistors of the same serial number; the resistance values of the four resistors on the units, tens, hundreds and thousands are configured by multiplying the factors of 8 / 80 / 800 / 8000, 4 / 40 / 400 / 4000, 2 / 20 / 200 / 2000 and 1 / 10 / 100 / 1000; the change of the resistance value on each digit can be realized by controlling the action of different relays, for example, when the relays K11, K12, K13 and K14 do not act, the corresponding normally closed contact is closed, then the four resistors on the units are short-circuited, and the resistance value is zero; when the relay K14 acts, the corresponding normally closed contact is opened, and the resistance value on the units is R14, i.e. 1, and the other resistance values are similar.

7. The remotely programmable resistor of claim 1, wherein: The input port of the master control module MCU is connected to one end of the 10k resistor and one end of the normally open contact of the relay, the other end of the 10k resistor is connected to the system power supply VCC, and the other end of the normally open contact of the relay is connected to the system power supply GND, thereby forming a state acquisition module and realizing the calculation of the output resistance value of the resistor.

8. The remotely programmable resistor of claim 1, wherein: The resistance rod is composed of a cylindrical handle (11), a cylindrical positioning baffle (12), a conductive upper copper ring (13), an upper resistance connecting screw (14), a resistance (15), a conductive lower copper ring (16) and a lower resistance connecting screw (17); the wires at both ends of the resistance (15) are connected to the conductive upper copper ring (13) and the conductive lower copper ring (16) through the upper resistance connecting screw (14) and the lower resistance connecting screw (17); and the resistance (15) is connected to the circuit network of the resistor through the conductive upper copper ring (13) and the conductive lower copper ring (16).

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