DC power supply control system

Abstract

The utility model relates to the technical field of power supply control, and discloses a direct-current power supply control system, which comprises an Ethernet switch, at least one programmable direct-current power supply, an upper computer and a programmable logic controller, the upper computer is connected with the Ethernet switch through a network port, and the programmable logic controller is connected with the Ethernet switch through a network port. The programmable logic controller operates a UDP polling communication program, and then the programmable logic controller sends an SCP I instruction to the programmable direct-current power supply and controls the output of the programmable direct-current power supply. The programmable logic controller collects key states or operation parameters of the programmable direct power supply, and the key states or the operation parameters are processed by the programmable logic controller and fed back to a human-computer interface of the upper computer. UDP communication and SCP I instructions are used, precision loss of analog-to-digital conversion does not exist in data, physical connection can be completed only through a network port, and hardware investment cost is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to power control technical field especially relates to a direct current power control system. BACKGROUND

[0002] The heater is one of the key equipment of the low temperature control system, and the low temperature control system carries out system rewarming, dewar liquid level regulation, working medium temperature regulation, liquid evaporation and gasification, liquidification rate and refrigerating capacity test and simulation load, and needs to start the heater to heat. Since the latent heat of low temperature liquid (such as liquid helium) is very small, the control precision of the heater is very high, therefore the traditional contactor and thyristor cannot be used to control the heater. Only the programmable direct current power supply with higher precision can be used to control. The traditional programmable control direct current power supply control method is to use 4-20mA analog quantity to control the programmable direct current power supply. However, this control mode has the precision loss of two times digital-analog conversion of the direct current power supply and PLC channel. And the analog quantity parameters provided by the direct current power supply are very limited. If it is needed to control and collect data of multiple programmable control direct current power supplies, a large number of PLC analog quantity channels need to be occupied, and the cost of the control system is increased. CONTENT OF UTILITY MODEL

[0003] Therefore, it is necessary to propose a direct current power supply control system in view of the technical problems of high cost and low precision of the prior art for controlling and collecting data of the direct current power supply. The direct current power supply control system comprises an Ethernet switch, at least one programmable direct current power supply, an upper computer and a programmable logic controller.

[0004] The programmable direct current power supply is connected with the Ethernet switch through a network port, the upper computer is connected with the Ethernet switch through a network port, and the programmable logic controller is connected with the Ethernet switch through a network port, wherein the programmable logic controller runs a UDP polling communication program, and the UDP polling communication program is encapsulated with a UDP communication instruction program, a polling communication program, a data processing program and a communication state monitoring program.

[0005] In an embodiment, the upper computer is a WinCC upper computer, the programmable logic controller is an S7-1500 series PLC, the programmable direct current power supply is a Dahua programmable direct current power supply, and the network port is an RJ45 network port.

[0006] The utility model discloses a direct current source control system, the direct current source control system includes: ethernet switch, at least one programmable direct current source, host computer, programmable logic controller, programmable direct current source with ethernet switch is connected through the network mouth, host computer with ethernet switch is connected through the network mouth, programmable logic controller with ethernet switch is connected through the network mouth, wherein, programmable logic controller runs UDP polling communication program, and the UDP polling communication program is encapsulated with UDP communication instruction program, polling communication program, data processing program, communication state monitoring program, the programmable logic controller of the utility model runs UDP polling communication program, and then, programmable logic controller sends SCPI instruction to single or multiple programmable direct current sources, realizes the control to the output of programmable direct current source, programmable logic controller gathers the key state or operating parameter of programmable direct current source, and after programmable logic controller program processing, feedback to the man-machine interface of host computer, because using UDP communication and SCPI instruction, data does not exist the precision loss of AD conversion, and physical connection only needs the network mouth and can be completed, reduces the cost of hardware investment. BRIEF DESCRIPTION OF DRAWINGS

[0007] In order to more clearly illustrate the technical scheme in the embodiment of the utility model or prior art, below will be to the drawing needed to use in the embodiment or prior art description simple introduction, obviously, the drawing in the following description only some embodiments of the utility model, for those skilled in the art, under the premise of not paying creative labor, can also obtain other drawings according to these drawings.

[0008] Among them:

[0009] Figure 1 It is the structure block diagram of direct current source control system in an embodiment;

[0010] Figure 2 It is the schematic diagram of UDP polling communication program of direct current source control system in an embodiment;

[0011] Figure 3 It is the schematic diagram of polling communication program of direct current source control system in an embodiment;

[0012] Figure 4 It is the schematic diagram of data processing program of direct current source control system in an embodiment;

[0013] Figure 5 It is the schematic diagram of communication data calling program of direct current source control system in an embodiment. DETAILED DESCRIPTION

[0014] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application; the use herein of terms such as "comprise" and "comprising", or "include" and "including" or "has" and "having" and any variations thereof, is intended to cover a non-exclusive inclusion; the use herein of terms such as "first", "second" and the like is intended to distinguish between similar objects unless the context indicates otherwise.

[0015] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another.

[0016] The technical solutions in the embodiments of the present application will be apparently and completely described in connection with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0017] Please refer to Figure 1 as shown, Figure 1 A flowchart of a direct-current power supply control system according to an embodiment of the present application is shown in the figure. The direct-current power supply control system comprises an Ethernet switch, at least one programmable direct-current power supply, an upper computer, and a programmable logic controller. The programmable direct-current power supply is connected to the Ethernet switch through a network port, the upper computer is connected to the Ethernet switch through a network port, and the programmable logic controller is connected to the Ethernet switch through a network port. The programmable logic controller runs a UDP polling communication program, which is encapsulated with a UDP communication instruction program, a polling communication program, a data processing program, and a communication state monitoring program.

[0018] In an embodiment, the upper computer is a WinCC upper computer, the programmable logic controller is an S7-1500 series PLC, the programmable direct-current power supply is a Dahua programmable direct-current power supply, and the network port is an RJ45 network port.

[0019] It needs to be explained that the common heater control method is PLC analog quantity control. Through the PLC analog quantity output channel, 4-20mA signal is output to control the output of the programmable DC power supply. In this control method, the DC power supply and the PLC channel are converted twice, and the precision of the transmitted data is lost. According to the progress of the analog channel, the error of two conversions may be 0.004. In the field of low temperature engineering, the programmable DC power supply needs to be controlled accurately, and the error of data conversion must be eliminated. At the same time, using analog quantity for output control and data acquisition will increase the number of analog quantity channels. If multiple programmable DC power supplies are controlled, the analog input and analog output modules must be increased. This will inevitably increase the cost of the control system.

[0020] In the embodiment, specifically, the utility model uses industrial Ethernet switch to compose industrial Ethernet network with WinCC host computer, S7-1500 series PLC and Dahua programmable DC power supply. First, UDP polling communication program is written by using Simatic TIA Portal V16 programming software, and S7-1500 series PLC runs the UDP polling communication program. Then, S7-1500 series PLC sends SCPI instruction to single or multiple Dahua programmable DC power supplies to control the output of the programmable DC power supply. S7-1500 series PLC collects the key state or operating parameter of the programmable DC power supply, processes it through PLC program and feeds it back to the human-machine interface of WinCC host computer. Because UDP communication and SCPI instruction are used, there is no precision loss of analog-digital conversion, and physical connection can be completed only by RJ45 network port, which reduces the cost of hardware investment.

[0021] Specifically. Figure 2 UDP polling communication program, UDP_COM_MUL is the FB function block of communication, which mainly encapsulates four function programs. The first part is the UDP communication instruction of TIA Portal software, the (TCON) instruction for establishing communication connection, the (TUSEND) instruction for data sending, the (TURCV) instruction for data receiving and the (TDICON) instruction for disconnecting communication connection. The second part is the polling communication program, which realizes the polling communication program by using CASE statement. The third part is the data processing program, which completes the sending and receiving of SCPI instruction. The fourth part is the communication state monitoring, which completes the monitoring of sending and receiving data. The RUN pin controls the start and stop of the UDP_COM_MUL FB function block, the POLLING pin displays the current work task, the TCON_DONE displays whether the connection is established, the TCON_ERROR displays the communication fault, the TUSEND_COUNT counts the sent data, and the TURCV_COUNT counts the received data.

[0022] Figure 3 is the schematic diagram of polling communication program, using CASE statement to complete the sequence control of polling communication. When the UDP polling communication program starts, the first step is to clear the WORK work area to send and receive data. The second step is to initialize the first task sequence number and the last task sequence number of the polling communication program, and make the value of #POLLING equal to the first task sequence number (after completing the first task, #POLLING will be added by "1", when POLLING is greater than or equal to the last task sequence number, the loop ends). The third step is to load the data of the REQUEST task area to the WORK work area, and send the data out. The fourth step is to start receiving data after the data sending is completed, and save the received data in the WORK work area buffer first, and then save the data to the REQUEST task area.

[0023] Figure 4 is the schematic diagram of data processing program, first read the SCPI command string length, such as SCPI instruction "VOLT?" to query the current voltage instruction, and split the instruction into CHAR character array. Then send the TUSEND instruction to the DC power supply. After receiving the instruction, the DC power supply responds. The data "5.00$L" of the DC power supply response is saved to the CHAR character array through the TURCV instruction, and the line feed "$L" is deleted, and the "5.00" voltage size data required by the program is extracted.

[0024] Figure 5 The schematic diagram of communication data calling program mainly completes the maximum current and voltage setting of Dahua power supply, and the current, voltage and power parameter processing. Among them: VOLT_SP_STR is the maximum voltage setting of the heater power supply, CURR_SP_STR is the maximum current setting of the heater power supply. VOLT_PV_STR is the maximum voltage feedback value of the heater power supply, CURR_PV_STR is the maximum current feedback value of the heater power supply. VOLT_MEAS_STR is the current voltage measurement value of the heater power supply, CURR_MEAS_STR is the current current measurement value of the heater power supply. POW_MEAS_STR is the current power measurement value of the heater power supply.

[0025] The DC power supply control system proposed in this embodiment includes an Ethernet switch, at least one programmable DC power supply, a host computer, and a programmable logic controller (PLC). The programmable DC power supply is connected to the Ethernet switch via a network port, the host computer is connected to the Ethernet switch via a network port, and the programmable logic controller is connected to the Ethernet switch via a network port. The programmable logic controller runs a UDP polling communication program, which encapsulates a UDP communication instruction program, a polling communication program, a data processing program, and a communication status monitoring program. The programmable logic controller runs the UDP polling communication program. The programmable logic controller then sends SCPI commands to one or more programmable DC power supplies to control their output. The programmable logic controller collects key status or operating parameters of the programmable DC power supply, processes them through the programmable logic controller program, and then feeds them back to the host computer's human-machine interface. Because UDP communication and SCPI commands are used, data does not suffer from accuracy loss due to analog-to-digital conversion. Physical connection requires only an RJ45 network port, reducing hardware investment costs.

[0026] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A direct current power supply control system, characterized by, The direct current power supply control system comprises an Ethernet switch, at least one programmable direct current power supply, an upper computer and a programmable logic controller; The programmable direct current power supply is connected with the Ethernet switch through a network port, the upper computer is connected with the Ethernet switch through a network port, and the programmable logic controller is connected with the Ethernet switch through a network port; The programmable logic controller is configured with a special FB function block for realizing a UDP polling communication program, the function block is integrated with the following pins: a RUN pin for controlling the start and stop of the FB function block, a POLLING pin for displaying a current work task, a TCON_DONE pin for displaying whether a connection is established, a TCON_ERROR pin for displaying a communication fault, a TUSEND_COUNT pin for counting sent data, and a TURCV_COUNT pin for counting received data; The upper computer is a WinCC upper computer, the programmable logic controller is an S7-1500 series PLC, the programmable direct current power supply is a Dahua programmable direct current power supply, and the network port is an RJ45 network port.

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