Switching value acquisition circuit and method

Abstract

The invention discloses a switching value acquisition circuit and method. The circuit comprises a control power supply state detection loop, an MCU signal acquisition control loop and at least one switching value acquisition loop. The switching value acquisition loop comprises a main acquisition optocoupler and an auxiliary acquisition optocoupler; and the MCU signal acquisition control loop is used for responding to the level signal detected by the control power supply state detection loop, controlling to disconnect the auxiliary acquisition optocoupler to acquire the switching value signal only through the main acquisition optocoupler, or controlling to start the auxiliary acquisition optocoupler and the main acquisition optocoupler to acquire the switching value signal together. According to the invention, different power supply voltage levels can be controlled; one group of optocoupler outputs or two groups of optocouplers are selected in parallel to output; the transmission gain of an acquisition loop is dynamically changed by acquiring the voltage of a control power supply, noise suppression thresholds required by different control power supply voltages can be met, the reliability of a circuit system is improved on the basis of the design of a passive device on a high-potential side, and meanwhile, the engineering debugging cost is reduced.

Description

technical field [0001] The invention relates to the technical field of industrial automation and relay protection, in particular to a switching value acquisition circuit and method. Background technique [0002] In the field of industrial automation and relay protection, in order to ensure the reliability of the control system, DC power supply is mostly used. When the capacity of the DC system is high, a lower control voltage is generally used to reduce the number of battery packs. For example, there are two kinds of control power supplies that are often used in the electric field: 110V DC and 220V DC. In these systems, because of the dual requirements of collecting the state of the main equipment and anti-electromagnetic interference, all switching signals are powered by the control power supply, connected to the control device by a strong current, and then rectified, filtered, stepped down, and current-limited. After being isolated by the optocoupler, it is sent to the ma...

AI Technical Summary

Problems solved by technology

[0003] In order to meet the needs of different control power supply voltages in engineering, it is often necessary to design two sets of different acquisition modules and use different step-down and current-limiting circuits, which gives the switch The production, debugging and on-site management of the acquisition module bring inconvenience and increase the cost of design and production

[0004] At present, there are ADC sampling method, FPGA-based pulse width detection method, variable reference comparator method, etc. for the control power system adaptive switching value acquisition method. It can solve the problem of switching value acquisition under different control power supply voltages to a certain extent, but there are also some shortcomings, such as complex system, troublesome debugging, poor circuit reliability, and difficult threshold setting.

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