Full-digital flow totalizer

Abstract

The invention relates to a full-digital flow totalizer which comprises an HART gateway (HME-635), a 250-ohm standard resistor, a PLC (a domestic tenium control PLC or an S7-200smartPLC), a touch screen (Kunlun on-state TP1071Gi), a switch, three network cables and an HART handheld communicator. According to the technical scheme, the full-digital flow totalizer is convenient and reliable to install, simple in transformation method, convenient to disassemble and assemble, low in cost and high in practicability. Digital transformation is realized by using existing equipment, the metering accuracy is improved, the system error of an original integrating instrument is 2.0%, the system error after transformation is 0.5%, the expandability is good, and an upper computer can interact with field equipment.

Description

Technical Field

[0001] This invention relates to a fully digital flow totalizer, belonging to the field of energy medium metering technology. Background Technology

[0002] Modern metering equipment consists of primary components (pressure taps), pressure guide pipes, ball valves, three-valve manifolds, pressure transmitters, differential pressure transmitters, and temperature sensors, forming a field measurement device. The field measurement equipment converts the measured physical quantities into standard (4-20) mA DC or (1-5) VDC values, which are then fed into a dedicated flow meter for instantaneous flow and cumulative flow calculations, displaying the results. The flow meter then uploads the calculated results to the monitoring system via a network.

[0003] Our unit previously used traditional single-unit totalizers for energy metering, with each totalizer connecting a maximum of four energy metering points. These traditional totalizers are now obsolete and no longer in production. The upgraded multi-channel totalizers still use analog signals (4-20) mAADC or (1-5) VDC input. The traditional method involves multiple analog-to-digital and digital-to-analog conversions, which affect the measurement data and cause distortion. Analog signals are also highly susceptible to interference. The improved method only requires one analog-to-digital conversion during transmitter measurement—the physical quantity at the site is converted to a digital signal. This digital signal is then directly acquired via a bus and processed directly in the flow totalizer. This eliminates the impact of other traditional transmission methods on the measurement signal. Summary of the Invention

[0004] This invention addresses the technical problems existing in the prior art by providing a fully digital flow totalizer. This technical solution is easy to install, reliable, simple to modify, easy to disassemble and assemble, and low in cost.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: a fully digital flow totalizer, the totalizer comprising a HART gateway (HME-635), a 250Ω standard resistor, a PLC (domestic Tenkong PLC or S7-200smart PLC), a touch screen (Kunlun Tongtai TP1071Gi), a switch, and three network cables, wherein the PLC, HART gateway, and touch screen are respectively connected to the switch via network cables, and the 250Ω standard resistor is connected in parallel to the HART bus port of the HART gateway, thus forming a fully digital flow totalizer.

[0006] The installation method is as follows: Improvements will be made to the existing metering electrical cabinet, as detailed below.

[0007] Step 1: Remove all power distribution units and integrators.

[0008] Step 2: Install the configured HART gateway (HME-635), the PLC with pre-installed software, the configured touch screen, and the switch.

[0009] Step 3: Connect a 250-ohm standard resistor in series in the power supply circuit of the field equipment.

[0010] Step 4: Connect a 250-ohm standard resistor in parallel on the HART bus of the HART gateway, and simultaneously connect a 250-ohm standard resistor in series in the power supply circuit of the field instruments.

[0011] Step 5: Connect the HART gateway's network port to the switch using a network cable.

[0012] Step 6: Connect the PLC network port to the switch using a network cable.

[0013] Step 7: Connect the touchscreen's network port to the switch using a network cable.

[0014] Step 8: Connect the 220VAC power cord to the PLC power interface via circuit breaker F3; connect it to the 24VDC power module power input interface via circuit breaker F2; connect the HART gateway power interface, switch power interface, and touch screen power interface to the 24VDC power module output power cord respectively. After checking that the wiring and connections in the electrical cabinet are correct, close the 220VAC main power circuit breaker F1 of the electrical cabinet.

[0015] Step 9: Close the air switches F2 and F3 inside the cabinet one by one.

[0016] Step 10: Use a handheld HART communicator to address each field device individually (address: 1~15).

[0017] Step 11: Set the corresponding parameters for each metering point on the touchscreen. This solution eliminates the power distributor and greatly simplifies the wiring within the cabinet. The equipment structure is simple, the layout is clear, and the field equipment can be directly connected to the improved flow totalizer without modification, reducing the impact of intermediate links on the acquired signal. Furthermore, this solution has good scalability; even if new energy metering points are added, no additional equipment needs to be added to the electrical cabinet.

[0018] Compared with the prior art, the present invention has the following advantages: 1) The technical solution improves the user-friendliness of parameter settings, making parameter settings more intuitive and easy to understand, and the operation is simple. The name of the measurement point can be directly edited on the screen, avoiding the trouble of pasted labels falling off.

[0019] 2) The required equipment is inexpensive and eliminates the need for a large number of power distribution units.

[0020] 3) The wiring inside the cabinet is simple and clear, reducing the workload of maintenance personnel.

[0021] 4) The HART gateway reads digital signals from various field testing devices, eliminating the biases associated with digital-to-analog and analog-to-digital conversion. Furthermore, the field devices all operate at a current of 4mA, contributing to energy efficiency. Additionally, there's no need to set ranges for the field testing devices; replacing spare parts simply requires configuring the address to reconnect them.

[0022] 5) The PLC and HART gateway exchange data using the ModBUS communication protocol. The PLC also possesses powerful computing capabilities, enabling it to calculate instantaneous flow and cumulative flow in real time.

[0023] 6) This HART gateway model has three channels, each capable of connecting up to 15 field devices, for a total of 45 field devices across all three channels. The system offers excellent scalability; adding new energy metering points requires no additional equipment within the cabinet. Further expansion is possible by adding more HART gateways.

[0024] 7) The touchscreen HMI interface can be customized to meet specific site needs and features access control; only users with the correct username and password can access the parameter setting screen, thus enhancing the security of measurement data.

[0025] 8) All parameters and cumulative values ​​are retained even after power failure. Data loss will not occur during power outages.

[0026] 9) The HART protocol can have two master devices (first master and second master). After the system is put into operation, it will not affect the access of portable HART communicators to view and adjust the devices.

[0027] 10) The calibration of on-site testing equipment is also simplified. For example, the calibration of pressure transmitters only requires inputting pressure through a standard pressure tester to directly read the corresponding pressure value. There is no need to connect a standard ammeter. The host computer communicates directly with the PLC, which can easily obtain information on all on-site testing equipment. At the same time, the status of on-site testing equipment can be viewed and set. Attached Figure Description

[0028] Figure 1 Schematic diagram of analog signal measurement for energy medium.

[0029] Figure 2 Schematic diagram of digital metering equipment.

[0030] Figure 3 HATR gateway and field device topology diagram

[0031] Figure 4 Electrical schematic diagram (wiring diagram) of digital metering equipment.

[0032] Figure 5 Touchscreen real-time display interface.

[0033] Figure 6 Metering point parameter setting interface.

[0034] In the picture:

[0035] Figure 1 1. Differential pressure transmitter; 2. Pressure transmitter; 3. Temperature sensor; 4. Power distributor 1; 5. Power distributor 2; 6. Power distributor 3; 7. Traditional integrator.

[0036] Figure 2 1. Differential pressure transmitter; 2. Pressure transmitter; 3. Temperature sensor; 8. HART gateway; 9. Switch; 10. PLC controller; 11. Touch screen.

[0037] Figure 3 12. 220V AC to 24V DC power supply module; 8. HART gateway; 17. 250Ω resistor; 20. Equipment operating power supply.

[0038] Figure 4 13. 220V AC power supply; 14. Air switch F1; 15. Air switch F2; 16. Air switch F3; 12. 220V AC to 24V DC power supply module; 10. PLC controller; 9. Switch; 8. HART gateway; 11. Touch screen; 17. 250Ω resistor; 1. Differential pressure transmitter; 2. Pressure transmitter; 3. Temperature sensor; 18. Field testing equipment 4; 19. Field testing equipment 5. Detailed Implementation

[0039] To enhance understanding of the present invention, the embodiments will be described in detail below with reference to the accompanying drawings.

[0040] Example 1: See Figure 1 , Figure 2 A fully digital flow totalizer is disclosed. The totalizer includes a HART gateway (HME-635), a 250Ω standard resistor, a PLC (domestic Tenkong PLC or S7-200smart PLC), a touch screen (Kunlun Tongtai TP1071Gi), a switch, and three network cables. The PLC, HART gateway, and touch screen are connected to the switch via network cables, and the 250Ω standard resistor is connected in parallel to the HART bus port of the HART gateway, forming a fully digital flow totalizer.

[0041] Will Figure 2The HART gateway, PLC, and touch screen are connected by network cables and switches to form a communication local area network. The IP addresses of the HART gateway, PLC, and touch screen must be set in the same network segment and have the same subnet mask.

[0042] First, after assigning a corresponding address to each device in the field using a handheld HART communicator, all field devices are connected in parallel to the data bus of the HART gateway. The corresponding register positions inside the HART gateway are set to store and read the real-time data collected by the field devices. The HART gateway and PLC communicate via the ModBUS protocol. The PLC reads the data from the gateway registers and substitutes the read data into the calculation formula in the PLC to calculate the real-time flow of the energy medium at the corresponding metering point. The PLC's accumulation program calculates the cumulative value and stores it in the power-off protection storage area. The touch screen and PLC read the real-time and cumulative data from the PLC's memory through the corresponding communication protocol and display it on the screen. At the same time, the touch screen sends the design parameters of the corresponding metering point to the PLC. The PLC stores the design parameters in the power-off protection storage area and substitutes them into the calculation formula to participate in the calculation of the flow of the corresponding metering point.

[0043] It should be noted that the above embodiments are not intended to limit the scope of protection of the present invention. Equivalent transformations or substitutions made based on the above technical solutions all fall within the scope of protection of the claims of the present invention.

Claims

1. A fully digital flow totalizer, characterized in that, The totalizer includes a HART gateway (HME-635), a 250Ω standard resistor, a PLC (a domestically produced Tenkong PLC or S7-200smart PLC), a touch screen (Kunlun Tongtai TP1071Gi), a switch, and three network cables. The PLC, HART gateway, and touch screen are connected to the switch via network cables, and the 250Ω standard resistor is connected in parallel to the HART bus port of the HART gateway, forming a fully digital flow totalizer.

2. The fully digital flow totalizer according to claim 1, characterized in that, The installation method is as follows: Improvements will be made to the existing metering electrical cabinet, as detailed below. Step 1: Remove all power distribution units and integrators. Step 2: Install the configured HART gateway (HME-635), the PLC with pre-installed software, the configured touch screen, and the switch. Step 3: Connect a 250-ohm standard resistor in series in the power supply circuit of the field equipment. Step 4: Connect a 250-ohm standard resistor in parallel on the HART bus of the HART gateway, and simultaneously connect a 250-ohm standard resistor in series in the power supply circuit of the field instruments. Step 5: Connect the HART gateway's network port to the switch using a network cable. Step 6: Connect the PLC network port to the switch using a network cable. Step 7: Connect the touchscreen's network port to the switch using a network cable. Step 8: Connect the 220VAC power cord to the PLC power interface via circuit breaker F3; connect it to the 24VDC power module power input interface via circuit breaker F2; connect the HART gateway power interface, switch power interface, and touch screen power interface to the 24VDC power module output power cord respectively. After checking that the wiring and connections in the electrical cabinet are correct, close the 220VAC main power circuit breaker F1 of the electrical cabinet. Step 9: Close the air switches F2 and F3 inside the cabinet one by one. Step 10: Use a handheld HART communicator to address each field device individually, address: 1~15. Step 11: Set the corresponding parameters for each metering point on the touch screen.

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