CN202798126U - Automatic switching system for uninterrupted power supply of PLC (programmable logic controller) - Google Patents

Abstract

The utility model provides an automatic switching system for uninterrupted power supply of a PLC (programmable logic controller). One end of a first power supply circuit breaker is connected with a 220V city power live wire, the other end of the first power supply circuit breaker is connected with a first live wire connection end of an uninterrupted power supply, a first zero wire connection end of the uninterrupted power supply is connected with a zero wire, one end of a second power supply circuit breaker is connected with the 220V city power live wire, the other end of the second power supply circuit breaker is connected with one end of a power supply switching relay, and a second zero wire connection end of the uninterrupted power supply and a zero wire connection end of the programmable logic controller are connected with the zero wire. A two-way automatic switching circuit is used for supplying power to the PLC, reliability is greatly improved, response speed is high by the aid of an automatic switching mode of the relay, manual intervention is omitted, alarm prompt is realized after switching, inspection and maintenance staff can immediately find the alarm promotion, and uninterrupted power supply of the PLC is ensured when the UPS (uninterrupted power supply) fails and is maintained.

Description

A PLC uninterrupted power supply automatic switching system

technical field

The utility model relates to a PLC uninterrupted power supply automatic switching system, which belongs to the technical field of PLC power supply switching systems.

Background technique

Programmable logic controller (PLC) has been widely used in industrial control systems. It is the core of the entire control system and the most important equipment to realize the automation of the whole plant. Once the PLC is accidentally powered off, the entire control system will be paralyzed. Therefore, the power supply of the PLC is reliable. Sexuality is critical in industrial control. At present, the automation industry generally adopts two methods for PLC power supply. The first is to directly take power from the power supply system and connect it to the PLC power module. The disadvantage of this method is obvious. When the power supply system fails, short circuit, tripping, etc., the PLC will immediately lose power and the automatic control system will be paralyzed. The second is to connect the UPS power supply in series before the PLC power module. When there is a power failure or the power supply system fails, the UPS supplies temporary power to the PLC, so as to buy a certain time for the technicians to troubleshoot and at the same time ensure the normal operation of the PLC. This method is commonly used at present, but its disadvantages are also obvious. First of all, UPS battery modules generally have a lifespan of 3 to 5 years. When it is close to the lifespan, it is prone to failure because it is connected in series with the PLC power supply circuit. Once a failure occurs, the PLC will lose power. Secondly, UPS needs regular maintenance, such as dust removal and deep discharge for its fans, which will inevitably affect the normal power supply of the PLC system. To sum up, neither of the two popular power supply methods can meet the high reliability requirements of PLC power supply.

Contents of the invention

The purpose of this utility model is to solve the problem that the two existing popular power supply methods cannot meet the high reliability requirements of PLC power supply, and further provide a PLC uninterrupted power supply automatic switching system.

The purpose of this utility model is achieved by the following technical solutions:

A PLC uninterrupted power supply automatic switching system, comprising: an uninterruptible power supply, a programmable controller, three power supply switching relays, a fuse, a power supply circuit breaker 1, a power supply circuit breaker 2 and a red prompting light, the power supply circuit One end of circuit breaker one is connected to the live wire of 220V mains, the other end of circuit breaker one of the power supply circuit is connected to the first live wire connection end of the uninterruptible power supply, and the first neutral wire connection end of the uninterruptible power supply is connected to the neutral wire. The connection end of the protection line of the uninterruptible power supply is connected to the protection line, one end of the power supply circuit breaker 2 is connected to the live wire of 220V mains, the other end of the power supply circuit breaker 2 is connected to one end of the power supply switching relay, and the power supply switching relay The other end is respectively connected with the second live wire connection end of the uninterruptible power supply and one end of the fuse, the other end of the fuse is connected with the live wire connection end of the programmable controller, the second neutral wire connection end of the uninterruptible power supply and the The zero line connection end of the programmable controller is connected with the zero line, the protection line connection end of the programmable controller is connected with the protection line, one end of the red prompt light is connected with the zero line, and the other end of the red prompt light is connected with the power supply switch One end of the relay is connected, the other end of the power supply switching relay is connected with the live wire of 220V mains, and the uninterruptible power supply is connected in parallel with the power supply switching relay.

The utility model has the advantages that: 1. The dual-way automatic switching circuit is adopted to provide power for the PLC, which greatly improves the reliability. 2. The switching adopts the relay automatic switching method, which has a fast response speed and does not require manual intervention. 3. There is an alarm prompt after switching, and inspection and maintenance personnel can find it immediately. 4. Make sure that when the UPS fails and is overhauled, the PLC will provide uninterrupted power supply. 5. The cost is low, and only a small amount of electrical components are added to realize the automatic switching function. 6. The design method is simple and easy, and users can implement it according to the design drawings and instructions at any time.

Description of drawings

Fig. 1 is a structural schematic diagram of a PLC uninterrupted power supply automatic switching system of the present invention.

Detailed ways

The utility model will be described in further detail below in conjunction with the accompanying drawings: the present embodiment is implemented under the premise of the technical solution of the utility model, and detailed implementation is provided, but the protection scope of the utility model is not limited to the following implementation example.

As shown in Figure 1, a PLC uninterruptible power supply automatic switching system involved in this embodiment includes: uninterruptible power supply UPS, programmable logic controller PLC, three power supply switching relays K1, fuse FU, power supply circuit breaker One F1, power supply circuit breaker two F2 and red warning light UPS ALARM, one end of the power supply circuit breaker one F1 is connected to the live wire L of 220V mains, the other end of the power supply circuit breaker one F1 is connected to the uninterruptible power supply UPS The connection end of the first live wire is connected, the first neutral wire connection end of the uninterruptible power supply UPS is connected with the neutral wire N, the protection wire connection end of the uninterruptible power supply UPS is connected with the protection wire PE, and one end of the circuit breaker F2 of the power supply circuit Connect with the 220V mains live wire L, the other end of the power supply circuit breaker F2 is connected with one end of the power supply switching relay K1, and the other end of the power supply switching relay K1 is respectively connected with the second live wire connection end of the uninterruptible power supply UPS and the fuse One end of the FU is connected, the other end of the fuse FU is connected to the fire wire connection end of the programmable controller PLC, and the second neutral wire connection end of the uninterruptible power supply UPS and the neutral wire connection end of the programmable controller PLC are both connected to the zero wire connection end of the programmable controller PLC. The line N is connected, the protection line connection end of the programmable controller PLC is connected to the protection line PE, one end of the red indicator light UPS ALARM is connected to the neutral line N, and the other end of the red indicator light UPS ALARM is connected to the power supply switching relay K1 One end is connected, the other end of the power supply switching relay K1 is connected with the 220V mains live line L, and the power supply switching relay K1 is connected in parallel on the uninterruptible power supply UPS.

It works as follows:

1. Under normal conditions, F1 and F2 are closed, UPS takes power from the mains, and outputs it to PLC and switching relay K1 through the right terminal, and the coil of K1 is closed, which is used for PLC power supply bypass and the normally closed contact of the indicator light. The point remains normally open, and the two paths are shorted. When the mains power is cut off or the power supply system fails, the UPS working status changes, and the battery is used to supply power to the PLC to ensure its uninterrupted work.

2. When the UPS fails and the UPS cannot output voltage normally, the K1 coil loses power and cannot be closed. The two normally closed contacts of K1 are immediately closed, and the PLC can directly take power from the mains grid, and automatically switch to Bypass power supply, and the UPS ALARM light is on, indicating that the UPS is not working and needs to be checked by maintenance personnel. At this time, no matter whether the UPS is repaired or replaced, it will not affect the PLC power supply system.

3. When the UPS needs to be cleaned or discharged for maintenance, manually pull down the UPS power supply gate F1, the UPS will automatically discharge to supply power to the PLC, and wait for the battery to run out. When the PLC automatically switches to the bypass power supply, the discharge work is completed and can be Remove its terminal wiring, maintain and clean it, not only to ensure the safety of the maintenance personnel but also to ensure the normal power supply of the PLC, and the UPS alarm light is always on during the whole process to remind the staff.

The above are only preferred specific implementations of the present utility model. These specific implementations are all based on different implementations under the overall concept of the present utility model, and the protection scope of the present utility model is not limited thereto. Anyone who is familiar with this utility model Any changes or replacements that can be easily conceived by those skilled in the technical field within the technical scope disclosed in the present utility model shall be covered by the protection scope of the present utility model. Therefore, the protection scope of the present utility model should be based on the protection scope of the claims.

Claims (1)

1. PLC uninterrupted power supply automatic switchover system; comprise: uninterrupted power supply; Programmable Logic Controller; three power switching relays; fuse; current supply circuit circuit breaker one; current supply circuit circuit breaker two and red warning light; it is characterized in that; one end of described current supply circuit circuit breaker one is connected with 220V civil power live wire; the other end of current supply circuit circuit breaker one is connected with the first live wire link of uninterrupted power supply; the first zero line link of uninterrupted power supply is connected with zero line; the protective wire link of uninterrupted power supply is connected with protective wire; one end of current supply circuit circuit breaker two is connected with 220V civil power live wire; the other end of current supply circuit circuit breaker two is connected with an end of power switching relay; the other end of power switching relay is connected with the second live wire link of uninterrupted power supply and an end of fuse respectively; the other end of fuse is connected with the live wire link of Programmable Logic Controller; the second zero line link of uninterrupted power supply and the zero line link of Programmable Logic Controller all are connected with zero line; the protective wire link of Programmable Logic Controller is connected with protective wire; one end of red warning light is connected with zero line; the other end of red warning light is connected with an end of power switching relay; the other end of power switching relay is connected with 220V civil power live wire, is parallel with the power switching relay on the uninterrupted power supply.

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