Siemens PLC-based double-pool circulating water constant pressure control system

Abstract

The utility model provides a double-pool circulating water constant-pressure control system based on a Siemens PLC (Programmable Logic Controller), which comprises a Siemens controller, and a Siemens frequency converter, a touch screen, a temperature inverter, a liquid level inverter, a pressure inverter, a cold water pump and a hot water pump which are in communication connection with the Siemens controller, the Siemens controller is connected with the cold water pump and the hot water pump through the Siemens frequency converter, the cold water pump is communicated with a water outlet of the cold water pool, an output end of the hot water pump is communicated with a water inlet of the cooling tower, and an input end of the hot water pump is communicated with a water outlet of the hot water pool. The temperature inverter is arranged at a water outlet of the cold water pump and used for detecting the temperature of the water outlet of the cold water pump. The liquid level inverters are respectively arranged on the cold water pool and the hot water pool and are used for detecting the liquid level of the cold water pool and the liquid level of the hot water pool; the pressure inverter is arranged at the water outlet of the cold water pump and used for detecting the pressure of the water outlet of the cold water pump. The control system can realize constant pressure control of workshop circulating water and constant liquid level control of the cold water pool.

Description

Technical Field

[0001] The utility model relates to the technical field of circulating water control, in particular to a double-tank circulating water constant pressure control system based on Siemens PLC. Background Art

[0002] Clean circulating water is mainly used for cooling and dissipating heat of workshop equipment. The water consumption of workshop equipment will fluctuate with the workshop production plan. However, the existing circulating water system cannot adjust the water supply pressure according to the change of water consumption, which leads to the workshop equipment requiring too much water to achieve a more ideal heat dissipation effect during the production process, or manual monitoring and adjustment of the water supply pressure, otherwise the ideal heat dissipation effect cannot be achieved, which results in a waste of resources, or is time-consuming and labor-intensive, and manual operation and adjustment are slow, inconvenient, inefficient, slow to respond, and the effect is poor.

[0003] In order to ensure the cooling effect of workshop equipment, improve the degree of automation and save energy, the utility model designs a double-tank circulating water constant pressure control system based on Siemens PLC to achieve constant pressure control of workshop circulating water and constant liquid level control of the cold water tank. Utility Model Content

[0004] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is:

[0005] A dual-tank circulating water constant pressure control system based on Siemens PLC, comprising a Siemens controller and a Siemens frequency converter, a touch screen, a temperature inverter, a liquid level inverter, a pressure inverter, a cold water pump, and a hot water pump, the Siemens controller being connected to the cold water pump and the hot water pump via the Siemens frequency converter, the cold water pump being connected to the water outlet of the cold water tank, the output end of the hot water pump being connected to the water inlet of the cold water tank, and the input end of the hot water pump being connected to the water outlet of the hot water tank; the temperature inverter being arranged at the water outlet of the cold water pump, and being used for detecting the temperature of the water outlet of the cold water pump; the liquid level inverter being arranged on the cold water tank and the hot water tank, respectively, and being used for detecting the liquid level of the cold water tank and the liquid level of the hot water tank; the pressure inverter being arranged at the water outlet of the cold water pump, and being used for detecting the pressure of the water outlet of the cold water pump.

[0006] Preferably, the Siemens controller is a Siemens SR60 controller.

[0007] Preferably, the Siemens frequency converter is an MM430 frequency converter, which is connected to the Siemens controller via an RS485 interface.

[0008] Preferably, the Siemens controller communicates with the touch screen via Ethernet via a PROFINET interface.

[0009] Preferably, there are four cold water pumps in total, one of which is a variable frequency pump and three are industrial frequency pumps. The three industrial frequency pumps operate alternately and periodically, and only one industrial frequency pump and the variable frequency pump operate simultaneously at a time.

[0010] Preferably, there are four hot water pumps in total, one of which is a variable frequency pump and three are industrial frequency pumps. The three industrial frequency pumps operate alternately and periodically, and only one industrial frequency pump and the variable frequency pump operate simultaneously at a time.

[0011] Preferably, the dual-tank circulating water constant pressure control system based on Siemens PLC also includes a high and low liquid level alarm module communicatively connected to the Siemens controller.

[0012] Preferably, the output end of the hot water pump is connected to the water inlet of the cold water tank through a cooling tower.

[0013] Compared with the prior art, the utility model has the following beneficial effects:

[0014] 1. The utility model adopts Siemens controller, analog input and output module, Siemens frequency converter, pressure inverter, touch screen and other components to quickly maintain the water supply pressure within the set pressure range, realize constant pressure control of workshop circulating water and constant liquid level control of cold water pool, ensure the cooling effect of workshop equipment, improve the degree of automation and save energy. The built-in PID control algorithm of Siemens controller can greatly improve the stability of constant pressure water supply. It has the advantages of significant energy saving effect, safety and stability, simple operation, labor saving, etc., and has certain promotion and application value.

[0015] 2. The Siemens controller adopted by the utility model has low cost, rich communication interfaces, rich expansion modules, stable control and fast response. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a system control block diagram of the utility model.

[0017] Figure 2 This is the water circuit diagram of a double-tank circulating water system.

[0018] The following specific implementation manner will further illustrate the present utility model in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0019] See also Figure 1In a preferred embodiment of the utility model, a dual-tank circulating water constant pressure control system based on Siemens PLC includes a Siemens controller and a Siemens frequency converter that is communicatively connected to the Siemens controller, a touch screen, a temperature inverter, a liquid level inverter, a pressure inverter, a cold water pump, and a hot water pump. The Siemens controller is connected to the cold water pump and the hot water pump through the Siemens frequency converter. The cold water pump is connected to the water outlet of the cold water tank, the output end of the hot water pump is connected to the water inlet of the cold water tank, and the input end of the hot water pump is connected to the water outlet of the hot water tank; the temperature inverter is arranged at the water outlet of the cold water pump to detect the temperature of the water outlet of the cold water pump; the liquid level inverter is respectively arranged on the cold water tank and the hot water tank to detect the liquid level of the cold water tank and the liquid level of the hot water tank; the pressure inverter is arranged at the water outlet of the cold water pump to detect the pressure of the water outlet of the cold water pump.

[0020] The utility model realizes constant pressure control of workshop circulating water and constant liquid level control of cold water pool through the above-mentioned arrangement, and has low control cost, stable control and fast response.

[0021] Specifically, the utility model uses a Siemens controller as a PLC controller, which has a good PID control algorithm and can greatly improve the stability of constant pressure water supply. In this embodiment, the Siemens controller adopts a Siemens SR60 controller. The Siemens frequency converter is an MM430 frequency converter, which is connected to the Siemens controller via an RS485 interface communication to perform USS communication, so that the Siemens controller can read relevant parameters of the Siemens frequency converter; and in order to prevent communication interference, the start and stop of the Siemens frequency converter is controlled by IO, and the frequency setting is given by the analog output module. In addition, the Siemens controller communicates with the touch screen via Ethernet through the PROFINET interface, and the touch screen adopts the Kunlun Tongtai touch screen. In this way, constant pressure control and data monitoring are achieved through the Siemens SR60 controller, the Siemens MM430 frequency converter and the Kunlun Tongtai touch screen.

[0022] In the utility model, the outlet temperature of the cold water pump, the outlet pressure of the cold water pump, the liquid level of the cold water pool, and the liquid level of the hot water pool are detected by setting a temperature inverter, a liquid level inverter, and a pressure inverter. The detected data is converted into digital by the analog input module of the Siemens controller. In order to prevent the abnormal shutdown of the pump caused by the failure of the liquid level inverter, the liquid level of the pool uses double liquid level detection. The program determines whether the inverter is good or bad. When it is normal, the average value of the liquid level is taken. When it is abnormal, the normal inverter liquid level value is automatically taken.

[0023] In this embodiment, the cold water pumps are provided with four units in total, one of which is a variable frequency pump, and three are industrial frequency pumps. The three industrial frequency pumps are operated alternately and periodically, and only one industrial frequency pump and the variable frequency pump are operated at the same time at a time. Similarly, the hot water pumps are provided with four units in total, one of which is a variable frequency pump, and three are industrial frequency pumps. The three industrial frequency pumps are operated alternately and periodically, and only one industrial frequency pump and the variable frequency pump are operated at the same time at a time. In other words, the cold water pump and the hot water pump are both four pumps, and when they are in operation, their operation mode is one variable frequency and one industrial frequency. The variable frequency pump is always in operation, and the three industrial frequency pumps are operated alternately, and periodic timing rotation is performed. The cold water pump of the utility model is mainly responsible for ensuring the outlet pressure of the cold water pool, and the hot water pump is responsible for the temperature of the liquid level of the cold water pool. When actually selecting the type, the corresponding pump head and motor are selected according to the actual water consumption. When applying, select the appropriate starting control according to the motor power. For cold water pumps with large power and large head, auto-coupling step-down starting can be adopted; for hot water pumps with small head and relatively low power, star-delta starting can be adopted. Considering the large head of cold water pumps, the power frequency pump should ensure that the valve is closed before starting the pump, start it without load, and slowly open the valve after the pump runs stably; before shutting down the pump, the valve should be closed before stopping the pump to avoid water hammer and pipeline impact. For hot water pumps, since the head of hot water pumps is generally small, they can be started and stopped directly.

[0024] It should be noted that, in the present embodiment, the output end of the hot water pump is connected to the water inlet of the cold water pool through the cooling tower, that is, the output end of the hot water pump is connected to the cooling tower, the cooling tower is connected to the water inlet of the cold water pool, the water outlet of the cold water pool is connected to the input end of the cold water pump, the output end of the cold water pump transports the cooling water to the workshop water equipment, the workshop water equipment flows the water into the hot water pool, the input end of the hot water pump is connected to the hot water pool, and the water in the hot water pool can be transported to the cooling tower, that is, the hot water pump, the cooling tower, the cold water pool, the cold water pump, the workshop water equipment, and the hot water pool constitute the following Figure 2 The circulating water circuit diagram is shown.

[0025] Finally, the dual-tank circulating water constant pressure control system based on Siemens PLC also includes a high and low liquid level alarm module that is communicated with the Siemens controller, so that the pump can be stopped in time when the liquid level is extremely low, an alarm can be given when the liquid level is too high or too low, and the valve can be automatically opened to replenish water when the total water storage capacity of the cold and hot water tanks is lower than the set value.

[0026] The above description is a detailed description of the preferred feasible embodiment of the utility model, but the embodiment is not used to limit the scope of the patent application of the utility model. All equivalent changes or modified changes completed under the technical spirit suggested by the utility model should fall within the patent scope covered by the utility model.

Claims

1. A dual-tank circulating water constant pressure control system based on Siemens PLC, characterized in that: It includes a Siemens controller and a Siemens frequency converter that is communicatively connected to the Siemens controller, a touch screen, a temperature inverter, a liquid level inverter, a pressure inverter, a cold water pump, and a hot water pump. The Siemens controller is connected to the cold water pump and the hot water pump through the Siemens frequency converter. The cold water pump is communicated with the water outlet of the cold water pool, the output end of the hot water pump is communicated with the water inlet of the cold water pool, and the input end of the hot water pump is communicated with the water outlet of the hot water pool; the temperature inverter is arranged at the water outlet of the cold water pump to detect the temperature of the water outlet of the cold water pump; the liquid level inverter is respectively arranged on the cold water pool and the hot water pool to detect the liquid level of the cold water pool and the liquid level of the hot water pool; the pressure inverter is arranged at the water outlet of the cold water pump to detect the pressure of the water outlet of the cold water pump.

2. A dual-tank circulating water constant pressure control system based on Siemens PLC as claimed in claim 1, characterized in that: The Siemens controller is a Siemens SR60 controller.

3. A dual-tank circulating water constant pressure control system based on Siemens PLC as claimed in claim 1, characterized in that: The Siemens frequency converter is an MM430 frequency converter, which is connected to the Siemens controller via an RS485 interface communication.

4. A dual-tank circulating water constant pressure control system based on Siemens PLC as claimed in claim 1, characterized in that: The Siemens controller communicates with the touch screen via Ethernet via a PROFINET interface.

5. A dual-tank circulating water constant pressure control system based on Siemens PLC as claimed in claim 1, characterized in that: There are four cold water pumps in total, one of which is a variable frequency pump and three are industrial frequency pumps. The three industrial frequency pumps operate alternately and periodically, and only one industrial frequency pump and the variable frequency pump operate simultaneously at a time.

6. A dual-tank circulating water constant pressure control system based on Siemens PLC as claimed in claim 1, characterized in that: There are four hot water pumps in total, one of which is a variable frequency pump and three are industrial frequency pumps. The three industrial frequency pumps operate alternately and periodically, and only one industrial frequency pump and the variable frequency pump operate simultaneously at a time.

7. A dual-tank circulating water constant pressure control system based on Siemens PLC as claimed in claim 1, characterized in that: It also includes a high and low level alarm module that is connected to the Siemens controller for communication.

8. A dual-tank circulating water constant pressure control system based on Siemens PLC as claimed in claim 1, characterized in that: The output end of the hot water pump is communicated with the water inlet of the cold water tank through a cooling tower.

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