JP3775954B2 - Electromagnetic switch - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for automatically returning to a state before a power failure when power is restored in an electromagnetically operated switch that is opened when a power failure occurs.
[0002]
[Prior art]
As a power switch for a load that is frequently turned on and off, an electromagnetically operated switch that operates an electromagnet having a long switching life to open and close a contact is often employed. For such a load, for example, when power is restored after a power failure for safety reasons, it is sometimes required to automatically return to the state before the power failure. Such a request cannot be realized by a simple electromagnetically operated switch composed of only an electromagnet and a contact.
[0003]
[Problems to be solved by the invention]
Some electromagnetically operated switches are equipped with a CPU as disclosed in Japanese Patent Application Laid-Open No. 2-136079, and operate an electromagnet in accordance with an opening / closing command to open / close the contacts of the main circuit. There are multi-function devices that perform current protection, but none satisfy the above requirements.
[0004]
Thus, in a switch using a CPU, a rewritable nonvolatile storage means called EEPROM is provided to always store the open / close state of the switch, and the stored contents are stored each time an ON operation or OFF operation is performed. In other words, when power is restored after a power failure, it is possible to easily return to the state before the power failure by reading the stored content and operating the switch based on the stored content.
[0005]
However, even though such a switch may be opened and closed several hundreds of thousands of times, the rewrite life of the EEPROM is about 10,000 times, and the life of both is not consistent. There was.
[0006]
Therefore, an object of the present invention is to provide an electromagnetically operated switch having a multiple open / close life that can be automatically restored to the open / close state before a power failure after power recovery.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides an electromagnetically operated switch that is controlled by an electronic controller that loses power when a power failure occurs and that opens and closes a contact. And a comparison means, and the storage means is a rewritable non-volatile storage means, each of which is sequentially written each time the switch is opened and closed with a pair of information on the open / close state of the switch and attribute information. And the writing means writes both information by sequentially circulating from the first storage space to the last storage space of the storage means for a number of opening / closing operations of the switch. Then, write one of two types of attribute information for all the spaces until writing to multiple storage spaces is completed, and switch the attribute information each time it completes a cycle. When the power is restored after a power failure, the comparison means compares the attribute information of the nth and (n + 1) th storage spaces written in the storage means, and if they are different, the comparison means writes them in the nth storage space. An open / close state is read and an operation signal is output to the switch.
[0008]
With such a configuration, the writing space is different every time the opening / closing operation is performed, so that the number of times of opening / closing can be accommodated by multiplying the rewrite life of the storage device by the number of divisions of the storage space. Furthermore, in the state before the power failure, writing is performed in order in a plurality of storage spaces, and the attribute information written until the first round is the same for each space, and the attribute information written is switched every round, When the attribute information is compared in order from the first storage space, it can be read that the storage content immediately before the attribute information is switched is the state before the power failure.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the examples shown in FIGS. Although not shown, this switch includes an open / close contact of a main circuit, an operating electromagnet that turns on the open / close contact only when energized, and a controller whose configuration is shown in FIG. This controller is a switch for selecting ON SW / OFF SW to operate the switch and whether to automatically return to the state before the power failure when power is restored (hereinafter referred to as “restart at power recovery”). SW input circuit for input to the CPU, CPU for processing the input signal including the EEPROM, MC control Ry for exciting or de-energizing the operation magnet of the switch, Ry for controlling the MC control Ry according to the processing of the CPU The drive circuit is included.
[0010]
FIG. 2 is a schematic flow chart of the operation of the controller, in which main function processing such as monitoring of an input signal and operation of a switch in response to the input signal and processing for restart at power recovery are performed.
[0011]
The RAM and EEPROM store information on restart setting at power recovery and current ON / OFF information of the switch. This EEPROM has first to forty write spaces for storing ON / OFF states. Each writing space can write 1-byte information, half of which is an attribute storage area, and the other half is a state storage area for storing the ON / OFF state of the switch. Two types of bit patterns (for example, 0101 and 1010, which will be described below using this example) are written in the attribute storage area. In addition, two types of bit patterns (eg, ON is 0000, OFF is 1111) are written in the state storage area depending on ON and OFF.
[0012]
Referring to FIG. 3, when the setting for restart at power recovery is added, the write process starts with any bit pattern (eg, 0101) in the attribute storage area in the first space. An OFF bit pattern (1111) is written in Next, when an ON signal is input, the signal is stored in the RAM, the MC control Ry is excited to turn on the switch, and the first space is stored in the attribute storage area of the second space of the EEPROM. The same bit pattern as the bit pattern (0101) is written into the state storage area as a bit pattern (0000) indicating ON. Next, when an OFF signal is input, the signal is stored in the RAM, the MC control Ry excitation is extinguished, the switch is turned OFF, and the second space is stored in the attribute storage area of the third space of the EEPROM. A bit pattern (1111) indicating OFF in the state storage area is written in the same bit pattern as the space bit pattern (0101). Similarly, every time an ON / OFF signal is input, the attribute and ON / OFF are sequentially switched in the order of the third space, the fourth space,..., The 39th space, and the 40th space. State is written. At this time, the same pattern is written in the attribute storage area up to the 40th space, and when the next ON / OFF signal is input after the 40th writing, the writing space is returned to the first space and the bit pattern of the attribute Is rewritten to the other (1010), and then rewritten to the same attribute pattern until the 40th write.
[0013]
In this way, the latest state is sequentially written through the 1st to 40th spaces, and the attribute is switched every time it goes around. That is, a bit pattern corresponding to ON / OFF is written in the state storage area, but the bit pattern written in the attribute storage area is one pattern (0101) in the first round for all the write spaces. The round is the other pattern (1010), the third is the one pattern (0101),..., (M-1) is the other pattern (1010), and the m-th is one pattern (0101). ... Different patterns are written alternately. Therefore, as shown in FIG. 4, the nth and (n + 1) th patterns are different, for example, the pattern of the nth attribute storage area is (0101) and the (n + 1) th pattern is (1010). In this case, the nth stored ON / OFF state is the latest state.
[0014]
In the flow chart of FIG. 2, in the initialization process when power is restored after a power failure, the state immediately before the power failure is stored in the RAM from the EEPROM to check whether there is a restart setting when power is restored. When the state immediately before the power failure is ON, a command to turn on the switch is issued. A flow for reading the state immediately before the power failure is shown in FIG. First, the attribute (0101) of the first space is determined, the number of the space is incremented by 1, and the determination of whether the attribute of the second space is the same as the attribute of the first space is sequentially repeated. . If the attribute (1010) of the (n + 1) th space is different from the attribute of the nth space, it means that a power failure has occurred when the switch is in the state stored in the nth space. The space number and attribute, and the ON / OFF state are stored. If the attribute does not change from the first to the 40th, it means that a power failure has occurred when the 40th space is stored, so the 40th space number, the attribute, and ON / OFF Remember the state.
[0015]
After such initialization processing, the MC control Ry is excited in the main processing flow to turn on the switch based on the above-described storage. Next, when an OFF signal is input, the same pattern as the nth bit pattern (0101) is written in the attribute storage area of the next space ((n + 1) th) of the write space (nth) immediately before the previous power failure. In the state storage area, a pattern (1111) corresponding to OFF is written. Thereafter, the writing is continued based on the flow of FIG. When the power is turned on for the first time after power recovery, the ON information may be written in the (n + 1) th space.
[0016]
By performing the processing as described above, even if an EEPROM having a write life of 10,000 times is used, a restart operation after power recovery can be performed for 400,000 open / close operations.
[0017]
Although the embodiment of the present invention has been described above, the embodiment of the present invention disclosed above is merely an example, and the scope of the present invention is limited to the embodiment of the above invention. It is not something. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[0018]
【The invention's effect】
The present invention is implemented in the form as described above, stores the switching state of the switch immediately before the occurrence of a power failure, and can automatically operate the switch to the state before the power failure when power is restored. Such a switch can be automatically turned on after the power is restored, and has the effect of ensuring safety.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a controller of an embodiment of an electromagnetically operated switch according to the present invention.
FIG. 2 is a schematic operation flowchart of the embodiment.
FIG. 3 is a flowchart of a write operation according to the embodiment.
FIG. 4 is a diagram illustrating a state written in the EEPROM of the embodiment.
FIG. 5 is a flowchart for reading a state before a power failure according to the embodiment.

Claims (2)

In an electromagnetically operated switch that is controlled by an electronic controller that loses power when a power failure occurs, and that the switching contact opens.
The controller has storage means, writing means, and comparing means,
The storage means is a rewritable nonvolatile storage means, and each of the storage means is divided into a plurality of pieces of information that are sequentially written each time the switch is opened and closed with a pair of information on the open / close state of the switch and attribute information. Have space,
The writing means sequentially circulates the information from the first storage space to the last storage space of the storage means for a number of opening / closing operations of the switch, and writes the both information. Write one of the two types of attribute information for all the spaces until the writing to the storage space is completed, and switch the attribute information every time it completes the cycle, and write the attribute information.
The comparison means compares the attribute information of the nth and (n + 1) th storage spaces written in the storage means when power is restored after a power failure, and stores the attribute information in the nth storage space if they are different. An electromagnetically operated switch that reads a written switch state and outputs an operation signal to the switch. 2. The electromagnetically operated switch according to claim 1, wherein each writing space is composed of 1 byte.

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