CN212364859U - Liquid level control system based on PLC - Google Patents
Liquid level control system based on PLC Download PDFInfo
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- CN212364859U CN212364859U CN202020674510.8U CN202020674510U CN212364859U CN 212364859 U CN212364859 U CN 212364859U CN 202020674510 U CN202020674510 U CN 202020674510U CN 212364859 U CN212364859 U CN 212364859U
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Abstract
The utility model provides a liquid level control system based on PLC, include: PLC control circuit, main circuit and auxiliary circuit, can switch over two kinds of modes of liquid level automatic control and liquid level manual control through mode change over switch 1SW, under manual mode, start the main pump motor through pressing button SB1, SB2 closes the main pump motor, realize the control to the liquid level, under automatic mode, detect the liquid level through level sensor, the PLC controller leads to/does not lead to according to liquid level control auxiliary relay coil, thereby control auxiliary circuit's contactor coil leads to/does not switch on, then make the main pump motor lead to/does not switch on, realize the control to the liquid level, the utility model discloses still be equipped with the stand-by pump, can work when the main pump trouble.
Description
Technical Field
The utility model relates to a liquid level control field, concretely relates to liquid level control system based on PLC.
Background
In the field of daily life and industrial production, the liquid level is controlled everywhere, at present, liquid level controllers are mostly used for liquid level control, the high and low liquid levels are controlled by a mechanical or electronic method, an electromagnetic valve, a water pump and the like can be controlled, and therefore semi-automation or full automation of liquid level control is achieved.
However, the existing liquid level controller has the problem of control accuracy caused by product quality, the liquid level controller often has no manual function, and the liquid level can not be controlled under the condition that the liquid level needs to be manually controlled.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to avoid the weak point among the prior art and provide a liquid level control system based on PLC, can control the liquid level through two kinds of modes of manual control and automatic control, improve liquid level control's the degree of accuracy.
The purpose of the utility model is realized through the following technical scheme: the utility model provides a liquid level control system based on PLC, include: the main circuit comprises a main pump motor M1 and a standby pump motor M2, the main pump motor M1 is connected with three-phase power through a first normally open contact of a contactor 1KM, and the standby pump motor M2 is connected with 380V three-phase power through a first normally open contact of a contactor 2 KM; the auxiliary circuit comprises a contactor 1KM coil and a contactor 2KM coil, wherein the contactor 1KM coil is connected with any phase of the three-phase power through a normally open contact of an intermediate relay KA1, and the contactor 2KM coil is connected with any phase of the three-phase power through a normally open contact of an intermediate relay KA 2; the PLC control circuit comprises a PLC controller, at least two intermediate relays, a mode switch 1SW, a liquid level sensor, a button SB1 and a button SB2, wherein a plurality of ports of the PLC controller are respectively connected with one end of all the intermediate relays, the other ends of all the intermediate relays are jointly connected with a DC24V end, one end of the mode switch 1SW is connected with a first port of the PLC controller, the other end of the mode switch 1SW is connected with a DC24V end, the liquid level sensor is connected with the PLC controller, one end of a contactor 1KM second normally open contact is connected with a second port of the PLC controller, the other end of a contactor 1KM second normally open contact is connected with one end of a contactor 2KM second normally open contact and a common end is connected with the DC24V end, the other end of the contactor 2KM second normally open contact is connected with a third port of the PLC controller, one end of the button SB1 is connected to the fourth port of the PLC controller, one end of the button SB2 is connected to the fifth port of the PLC controller, and the other end of the button SB1 is connected to the other end of the button SB2 and the common terminal DC 24V-terminal.
Preferably, the main circuit further comprises a thermal relay 1KH, a thermal relay 2KH, a circuit breaker 1QF and a circuit breaker 2QF, wherein one end of the thermal relay 1KH is connected with the main pump motor M1, the other end of the thermal relay 1KH is connected with one end of a first normally open contact of the contactor 1KM, the other end of the first normally open contact of the contactor 1KM is connected with one end of the circuit breaker 1QF, and the other end of the circuit breaker 1QF is connected with the three-phase power; one end of thermal relay 2KH is connected stand-by pump motor M2, the other end of thermal relay 2KH is connected the one end of the first normally open contact of contactor 2KM, the other end of the first normally open contact of contactor 2KM is connected the one end of circuit breaker 2QF, the other end of circuit breaker 2QF is connected the three-phase electricity.
Preferably, the PLC control circuit further includes an intermediate relay KA1, an intermediate relay KA2, an intermediate relay KA3, and an intermediate relay KA 4.
Preferably, the auxiliary circuit further comprises a contactor 1KM state indicating circuit, a contactor 2KM state indicating circuit, an intermediate relay KA1 state indicating circuit, an intermediate relay KA2 state indicating circuit, an intermediate relay KA3 state indicating circuit and an intermediate relay KA4 state indicating circuit; contactor 1KM state indicating circuit includes fuse FU1, contactor 1KM normally closed contact, pilot lamp HD1-1 and fuse FU2 that connect gradually, contactor 2KM state indicating circuit includes fuse FU3, contactor 2KM normally closed contact, pilot lamp HD1-2 and fuse FU4 that connect gradually.
Preferably, the intermediate relay KA1 and KA2 status indication circuits comprise a fuse FU5, a fuse FU6, an intermediate relay KA1 normally open contact, a contactor 1KM coil, an indicator lamp HD2-1, an intermediate relay KA2 normally open contact, a contactor 2KM coil and an indicator lamp HD2-2, one end of the fuse FU5 is connected with any one of three-phase power, the other end of the fuse FU5 is connected with one end of the intermediate relay KA1 normally open contact and the common end is connected with one end of the intermediate relay KA2 normally open contact, the other end of the intermediate relay KA1 normally open contact is connected with one end of the contactor 1KM coil and the common end is connected with one end of the indicator lamp HD2-1, the other end of the contactor 1KM coil is connected with the other end of the indicator lamp 89HD 36-1 and the common end is connected with one end of the fuse FU6, fuse FU 6's the other end is connected the zero line N of three-phase electricity, the one end of auxiliary relay KA2 normally open contact is connected fuse FU 5's the other end, the other end of auxiliary relay KA2 normally open contact is connected the one end and the common terminal of contactor 2KM coil are connected the one end of pilot lamp HD2-2, the other end of contactor 2KM coil is connected the other end and the common terminal of pilot lamp HD2-2 are connected the one end of fuse FU 6.
Preferably, the intermediate relay KA3 status indicating circuit and the intermediate relay KA4 status indicating circuit comprise a fuse FU7, an intermediate relay KA3 normally open contact, an indicator lamp HD3, a fuse FU8, an intermediate relay KA4 normally open contact and an indicator lamp FD, one end of the fuse FU7 is connected with any one of three-phase power, the other end of the fuse FU7 is connected with one end of the normally open contact of the intermediate relay KA3, the common end of the fuse FU7 is connected with one end of the normally open contact of the intermediate relay KA4, the other end of the normally open contact of the intermediate relay KA3 is connected with one end of the indicator light HD3, the other end of the normally open contact of the intermediate relay KA4 is connected with one end of the indicator lamp FD, the other end of pilot lamp HD3 is connected the other end and the common terminal of pilot lamp FD are connected the one end of fuse FU8, the other end of fuse FU8 is connected the zero line N of three-phase electricity.
Preferably, the PLC control circuit also comprises a button SB3, a button SB4, a normally closed contact of a thermal relay 1KH and a normally closed contact of a thermal relay 2KH, one end of the button SB1 is connected to the fourth port of the PLC controller, one end of the button SB2 is connected to the fifth port of the PLC controller, one end of the button SB3 is connected to the sixth port of the PLC controller, one end of the button SB4 is connected to the seventh port of the PLC controller, one end of the thermal relay 1KH normally closed contact is connected with the eighth port of the PLC, one end of the thermal relay 1KH normally closed contact is connected with a ninth port of the PLC, the other end of the button SB1, the other end of the button SB3, the other end of the button SB4, the other end of the normally closed contact of the thermal relay 1KH and the other end of the normally closed contact of the thermal relay 2KH are connected to a DC 24-terminal.
According to the above technical scheme, the utility model discloses following beneficial effect has: the utility model provides a liquid level control system based on PLC, can switch over two kinds of modes of liquid level automatic control and liquid level manual control through mode change over switch 1SW, under manual mode, start the main pump motor through pressing button SB1, press button SB2 and close the main pump motor, the realization is to the control of liquid level, under automatic mode, detect the liquid level through level sensor, the PLC controller leads to/does not lead to according to liquid level control auxiliary relay coil, thereby control auxiliary circuit's contactor coil leads to/does not switch on, then make the main pump motor switch on/do not switch on, realize the control to the liquid level, the utility model discloses still be equipped with the stand-by pump, can work when the main pump trouble.
Drawings
The invention is further described with the aid of the accompanying drawings, in which, however, the embodiments do not constitute any limitation to the invention, and for a person skilled in the art, other drawings can be derived from the following drawings without inventive effort.
Fig. 1 is a circuit structure diagram of the PLC control circuit of the present invention.
Fig. 2 is a circuit configuration diagram of the main circuit of the present invention.
Fig. 3 is a circuit configuration diagram of the auxiliary circuit of the present invention.
Detailed Description
In order to make the technical solution of the present invention better understood, the technical solution of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments.
As shown in fig. 1-3, the PLC-based liquid level control system of the present embodiment includes: the main circuit comprises a main pump motor M1 and a standby pump motor M2, the main pump motor M1 is connected with three-phase power through a first normally open contact of a contactor 1KM, and the standby pump motor M2 is connected with 380V three-phase power through a first normally open contact of a contactor 2 KM; the auxiliary circuit comprises a contactor 1KM coil and a contactor 1KM coil, wherein the contactor 1KM coil is connected with any phase of the three-phase power through a normally open contact of an intermediate relay KA1, and the contactor 1KM coil is connected with any phase of the three-phase power through a normally open contact of an intermediate relay KA 2; the PLC control circuit comprises a PLC controller, at least two intermediate relays, a mode switch 1SW, a liquid level sensor, a button SB1 and a button SB2, wherein one ends of all the intermediate relays are respectively connected with a plurality of ports of the PLC controller, the other ends of all the intermediate relays are jointly connected with a DC24V end, one end of the mode switch 1SW is connected with a Dia.0 port of the PLC controller, the other end of the mode switch 1SW is connected with a DC24V end, the liquid level sensor is connected with the PLC controller, one end of a contactor 1KM second normally open contact is connected with a Dia.7 port of the PLC controller, the other end of a contactor 1KM second normally open contact is connected with one end of a contactor 2KM second normally open contact and a common end is connected with a DC24V end, the other end of the contactor 2KM second normally open contact is connected with a Dib.0 port of the PLC controller, one end of the button SB1 is connected with the Dia.1 port of the PLC controller, one end of the button SB2 is connected with the Dia.2 port of the PLC controller, the other end of the button SB1 is connected with the other end of the button SB2, and the common end is connected with the DC 24V-end.
In this embodiment, the PLC control circuit further includes an intermediate relay KA1, an intermediate relay KA2, an intermediate relay KA3 and an intermediate relay KA4, the mode switching switch 1SW can switch two modes of liquid level automatic control and liquid level manual control, in the automatic mode, the liquid level sensor can acquire liquid level information, convert the liquid level information into a digital signal and input the digital signal into the PLC controller, the PLC controller can control the intermediate relay KA1, the intermediate relay KA2, the intermediate relay KA3 and the intermediate relay KA4 to be electrified or not electrified through output signals, the intermediate relay KA1 and the intermediate relay KA2 are electrified or not electrified to change the contact switch states of the intermediate relay KA1 and the intermediate relay KA2, therefore, the contactor is electrified or not electrified in the auxiliary circuit, and the main pump motor/the standby pump motor is electrified or not electrified by the electrified or not electrified contactor, so that the control of the main pump motor/the standby pump motor is realized according to the liquid level information.
The main circuit further comprises a thermal relay 1KH, a thermal relay 2KH, a circuit breaker 1QF and a circuit breaker 2QF, one end of the thermal relay 1KH is connected with the main pump motor M1, the other end of the thermal relay 1KH is connected with one end of a first normally open contact of the contactor 1KM, the other end of the first normally open contact of the contactor 1KM is connected with one end of the circuit breaker 1QF, and the other end of the circuit breaker 1QF is connected with the three-phase power; one end of thermal relay 2KH is connected stand-by pump motor M2, the other end of thermal relay 2KH is connected the one end of the first normally open contact of contactor 2KM, the other end of the first normally open contact of contactor 2KM is connected the one end of circuit breaker 2QF, the other end of circuit breaker 2QF is connected the three-phase electricity.
When the main pump motor/the standby pump motor are overloaded, the thermal relay coil changes the state of a contact switch of the thermal relay, and the circuit breaker is used for enabling the main pump motor/the standby pump motor to be connected with/not connected with three-phase power.
The auxiliary circuit further comprises a contactor 1KM state indicating circuit, a contactor 2KM state indicating circuit, an intermediate relay KA1 state indicating circuit, an intermediate relay KA2 state indicating circuit, an intermediate relay KA3 state indicating circuit and an intermediate relay KA4 state indicating circuit; contactor 1KM state indicating circuit includes fuse FU1, contactor 1KM normally closed contact, pilot lamp HD1-1 and fuse FU2 that connect gradually, contactor 2KM state indicating circuit includes fuse FU3, contactor 2KM normally closed contact, pilot lamp HD1-2 and fuse FU4 that connect gradually.
The intermediate relay KA1 state indicating circuit and the intermediate relay KA2 state indicating circuit comprise a fuse FU5, a fuse FU6, an intermediate relay KA1 normally-open contact, a contactor 1KM coil, an indicator lamp HD2-1, an intermediate relay KA2 normally-open contact, a contactor 2KM coil and an indicator lamp HD2-2, one end of the fuse FU5 is connected with any one of three-phase power through a breaker 4QF, the other end of the fuse FU5 is connected with one end of the intermediate relay KA1 normally-open contact, the common end of the fuse FU is connected with one end of the intermediate relay KA2 normally-open contact, the other end of the intermediate relay KA1 normally-open contact is connected with one end of the contactor 1KM coil, the common end of the indicator lamp HD2-1 is connected with one end of the indicator lamp HD2-1, the other end of the contactor 1KM coil is connected with the other end of the, fuse FU 6's the other end passes through the circuit breaker 4QF and connects the zero line N of three-phase electricity, the one end of auxiliary relay KA2 normally open contact is connected fuse FU 5's the other end, the other end of auxiliary relay KA2 normally open contact is connected the one end and the common port of contactor 2KM coil are connected pilot lamp HD 2-2's one end, the other end of contactor 2KM coil is connected the other end and the common port of pilot lamp HD2-2 are connected the one end of fuse FU 6.
The intermediate relay KA3 state indicating circuit and the intermediate relay KA4 state indicating circuit comprise a fuse FU7, an intermediate relay KA3 normally open contact, an indicator light HD3, a fuse FU8, an intermediate relay KA4 normally open contact and an indicator light FD, one end of the fuse FU7 is connected with any one of three-phase electricity through a breaker 4QF, the other end of the fuse FU7 is connected with one end of the normally open contact of the intermediate relay KA3, the common end of the fuse FU7 is connected with one end of the normally open contact of the intermediate relay KA4, the other end of the normally open contact of the intermediate relay KA3 is connected with one end of the indicator light HD3, the other end of the normally open contact of the intermediate relay KA4 is connected with one end of the indicator lamp FD, the other end of the indicator light HD3 is connected to the other end of the indicator light FD and the common terminal is connected to one end of the fuse FU8, the other end of the fuse FU8 is connected with a zero line N of the three-phase power through a circuit breaker 4 QF.
In the embodiment, the fuse FU1-FU8 is used for overcurrent protection of the auxiliary circuit, the indicator light HD1-1 is used for indicating the state of the contactor 1KM, specifically, the indicator light HD1-1 is bright to indicate that the contactor 1KM is not electrified, the indicator light HD1-1 is bright to indicate that the contactor 1KM is electrified, the indicator light HD-2 is used for indicating the state of the contactor 2KM, the indicator light HD2-1 is used for indicating the state of the intermediate relay KA1, the indicator light HD2-1 is used for indicating the state of the intermediate relay KA2, the indicator light HD3 is used for indicating the state of the intermediate relay KA3, and the indicator light FD is used for indicating the state of the intermediate relay KA4, when the normally open contact of the intermediate relay KA1 is closed, the contactor 1KM is electrified, when the normally open contact of the intermediate relay KA2 is closed, the contactor 2KM is electrified, and the circuit breaker 4QF controls the auxiliary circuit to be connected into/not connected into three-phase power.
PLC control circuit still includes button SB3, button SB4, thermal relay 1KH normally closed contact, thermal relay 2KH normally closed contact, the one end of button SB1 is connected the fourth port of PLC controller, the Dia.5 port of PLC controller is connected to the one end of button SB3, the Dia.6 port of PLC controller is connected to the one end of button SB4, the Dia.3 port of PLC controller is connected to the one end of thermal relay 1KH normally closed contact, the Dia.4 port of PLC controller is connected to the one end of thermal relay 1KH normally closed contact, the other end of button SB1, the other end of button SB3, the other end of button SB4, the other end of thermal relay 1KH normally closed contact and the other end of thermal relay 2KH normally closed contact connect DC 24-end jointly.
Button SB3, button SB4 can set up to the test according to the demand, the fault resetting, functions such as manual control, in this embodiment, button SB3 is used for reseing, button SB4 is used for starting the test, when the main pump motor transships when heat relay 1KH normally closed contact, the disconnection of heat relay 1KH normally closed contact, the main pump motor overload information is received promptly to the PLC controller, PLC sends alarm information, the working method of reserve pump motor is with the main pump motor, contactor 1KM second normally open contact and contactor 2KM second normally open contact are used for the operating condition to PLC controller feedback contactor 1KM and contactor 2 KM.
The working principle of the embodiment is as follows: according to the implementation, two modes of liquid level automatic control and liquid level manual control can be switched through a mode switching switch 1SW, in the manual mode, a button SB1 is pressed, the power-on of an intermediate relay KA1 is controlled through a PLC controller, after the intermediate relay KA1 is powered on, a normally open contact of the intermediate relay KA1 in an auxiliary circuit is closed, so that a contactor 1KM is powered on, after the contactor 1KM is powered on, a first normally open contact of the contactor 1KM is closed, a main pump motor is started, the liquid level is controlled, after the button SB2 is pressed, the PLC controller stops a main pump motor, and the starting principle of a standby pump motor is the same as that of the main pump motor; under automatic mode, detect the liquid level through level sensor, when the liquid level is low excessively, the PLC controller is according to liquid level information control auxiliary relay coil KA1 circular telegram, make auxiliary circuit's auxiliary relay KA 1's normally open contact closed after auxiliary relay KA1 circular telegram, thereby make contactor 1KM circular telegram, contactor 1KM circular telegram back, the first normally open contact of contactor 1KM is closed, thereby start the main pump motor, realize the control to the liquid level, the reserve pump motor start principle is the same with the main pump motor.
It should be finally noted that the above embodiments are only intended to illustrate the technical solutions of the present invention, and not to limit the scope of the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention can be modified or replaced with equivalents without departing from the spirit and scope of the technical solutions of the present invention.
Claims (7)
1. A PLC-based liquid level control system, comprising: the main circuit comprises a main pump motor M1 and a standby pump motor M2, the main pump motor M1 is connected with three-phase power through a first normally open contact of a contactor 1KM, and the standby pump motor M2 is connected with 380V three-phase power through a first normally open contact of a contactor 2 KM; the auxiliary circuit comprises a contactor 1KM coil and a contactor 2KM coil, wherein the contactor 1KM coil is connected with any phase of the three-phase power through a normally open contact of an intermediate relay KA1, and the contactor 2KM coil is connected with any phase of the three-phase power through a normally open contact of an intermediate relay KA 2; the PLC control circuit comprises a PLC controller, at least two intermediate relays, a mode switch 1SW, a liquid level sensor, a button SB1 and a button SB2, wherein a plurality of ports of the PLC controller are respectively connected with one end of all the intermediate relays, the other ends of all the intermediate relays are jointly connected with a DC24V end, one end of the mode switch 1SW is connected with a first port of the PLC controller, the other end of the mode switch 1SW is connected with a DC24V end, the liquid level sensor is connected with the PLC controller, one end of a contactor 1KM second normally open contact is connected with a second port of the PLC controller, the other end of a contactor 1KM second normally open contact is connected with one end of a contactor 2KM second normally open contact and a common end is connected with the DC24V end, the other end of the contactor 2KM second normally open contact is connected with a third port of the PLC controller, one end of the button SB1 is connected to the fourth port of the PLC controller, one end of the button SB2 is connected to the fifth port of the PLC controller, and the other end of the button SB1 is connected to the other end of the button SB2 and the common terminal DC 24V-terminal.
2. The PLC-based level control system of claim 1, wherein: the main circuit further comprises a thermal relay 1KH, a thermal relay 2KH, a circuit breaker 1QF and a circuit breaker 2QF, one end of the thermal relay 1KH is connected with the main pump motor M1, the other end of the thermal relay 1KH is connected with one end of a first normally open contact of the contactor 1KM, the other end of the first normally open contact of the contactor 1KM is connected with one end of the circuit breaker 1QF, and the other end of the circuit breaker 1QF is connected with the three-phase power; one end of thermal relay 2KH is connected stand-by pump motor M2, the other end of thermal relay 2KH is connected the one end of the first normally open contact of contactor 2KM, the other end of the first normally open contact of contactor 2KM is connected the one end of circuit breaker 2QF, the other end of circuit breaker 2QF is connected the three-phase electricity.
3. The PLC-based level control system of claim 1, wherein: the PLC control circuit further comprises an intermediate relay KA1, an intermediate relay KA2, an intermediate relay KA3 and an intermediate relay KA 4.
4. The PLC-based level control system of claim 3, wherein: the auxiliary circuit further comprises a contactor 1KM state indicating circuit, a contactor 2KM state indicating circuit, an intermediate relay KA1 state indicating circuit, an intermediate relay KA2 state indicating circuit, an intermediate relay KA3 state indicating circuit and an intermediate relay KA4 state indicating circuit; contactor 1KM state indicating circuit includes fuse FU1, contactor 1KM normally closed contact, pilot lamp HD1-1 and fuse FU2 that connect gradually, contactor 2KM state indicating circuit includes fuse FU3, contactor 2KM normally closed contact, pilot lamp HD1-2 and fuse FU4 that connect gradually.
5. The PLC-based level control system of claim 4, wherein: the intermediate relay KA1 state indicating circuit and the intermediate relay KA2 state indicating circuit comprise a fuse FU5, a fuse FU6, an intermediate relay KA1 normally-open contact, a contactor 1KM coil, an indicator lamp HD2-1, an intermediate relay KA2 normally-open contact, a contactor 2KM coil and an indicator lamp HD2-2, one end of the fuse FU5 is connected with any one of three phases of electricity, the other end of the fuse FU5 is connected with one end of the intermediate relay KA1 normally-open contact, the common end of the fuse FU is connected with one end of the intermediate relay KA2 normally-open contact, the other end of the intermediate relay KA1 normally-open contact is connected with one end of the contactor 1KM coil, the common end of the fuse FU1 is connected with one end of the indicator lamp HD2-1, the other end of the contactor 1KM coil is connected with the other end of the indicator lamp HD 89, fuse FU 6's the other end is connected the zero line N of three-phase electricity, the one end of auxiliary relay KA2 normally open contact is connected fuse FU 5's the other end, the other end of auxiliary relay KA2 normally open contact is connected the one end and the common terminal of contactor 2KM coil are connected the one end of pilot lamp HD2-2, the other end of contactor 2KM coil is connected the other end and the common terminal of pilot lamp HD2-2 are connected the one end of fuse FU 6.
6. The PLC-based level control system of claim 4, wherein: the intermediate relay KA3 state indicating circuit and the intermediate relay KA4 state indicating circuit comprise a fuse FU7, an intermediate relay KA3 normally open contact, an indicator light HD3, a fuse FU8, an intermediate relay KA4 normally open contact and an indicator light FD, one end of the fuse FU7 is connected with any one of three-phase power, the other end of the fuse FU7 is connected with one end of the normally open contact of the intermediate relay KA3, the common end of the fuse FU7 is connected with one end of the normally open contact of the intermediate relay KA4, the other end of the normally open contact of the intermediate relay KA3 is connected with one end of the indicator light HD3, the other end of the normally open contact of the intermediate relay KA4 is connected with one end of the indicator lamp FD, the other end of pilot lamp HD3 is connected the other end and the common terminal of pilot lamp FD are connected the one end of fuse FU8, the other end of fuse FU8 is connected the zero line N of three-phase electricity.
7. The PLC-based level control system of claim 1, wherein: PLC control circuit still includes button SB3, button SB4, thermal relay 1KH normally closed contact, thermal relay 2KH normally closed contact, the one end of button SB3 is connected the sixth port of PLC controller, the seventh port of PLC controller is connected to the one end of button SB4, the eighth port of PLC controller is connected to the one end of thermal relay 1KH normally closed contact, the ninth port of PLC controller is connected to the one end of thermal relay 1KH normally closed contact, the other end of button SB2, the other end of button SB3, the other end of button SB4, the other end of thermal relay 1KH normally closed contact and the other end of thermal relay 2KH normally closed contact connect DC 24-end jointly.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020674510.8U CN212364859U (en) | 2020-04-28 | 2020-04-28 | Liquid level control system based on PLC |
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| CN202020674510.8U CN212364859U (en) | 2020-04-28 | 2020-04-28 | Liquid level control system based on PLC |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112904267A (en) * | 2021-01-19 | 2021-06-04 | 南京钢铁股份有限公司 | Automatic switching method for standby pump in electrical soft fault |
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2020
- 2020-04-28 CN CN202020674510.8U patent/CN212364859U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112904267A (en) * | 2021-01-19 | 2021-06-04 | 南京钢铁股份有限公司 | Automatic switching method for standby pump in electrical soft fault |
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