A plc with configurable level signal output mode

Abstract

The invention discloses a PLC (programmable logic controller) with a level signal output mode configuration function. The PLC comprises a PLC internal processing circuit, an output circuit and a level signal output mode conversion circuit. The output circuit comprises a plurality of triodes, a base electrode of each triode is electrically connected with the PLC internal processing circuit, and a collector electrode of each triode is electrically connected with a corresponding output terminal. The level signal output mode conversion circuit comprises a plurality of resistors in parallel connection, one end of each resistor is connected with the collector electrode of the corresponding triode and the corresponding output terminal, and the other end of each resistor is connected with a power source end through the same switch. By the PLC, conversion among PLC output level signals is achieved through downward pulling or upward pulling of the resistors under PLC internal integration without replacement of the PLC, and requirements of different input level signals of an external circuit are met, so that production cost is saved, technology complexity is lowered, time is saved, and working progress is accelerated.

Description

technical field [0001] The invention relates to the field of industrial automation network control systems, in particular to a PLC with a configurable level signal output mode. Background technique [0002] At present, PLC (Programmable Logic Controller, Programmable Logic Controller) is widely used in the field of industrial automation systems due to its stable and reliable advantages, but in actual products, generally PLC can only output one level signal (such as high signal or low signal), when the external circuit needs another level input signal, the current PLC cannot meet the needs of the external circuit. [0003] In the prior art, there are two methods to meet the requirements of the external circuit: one, replace the current PLC to a PLC with another level output signal; The pull-up resistor performs conversion of the level output signal. The inventors found that both methods have shortcomings, and the shortcomings are: in the first method, the production cost an...

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Problems solved by technology

The inventors found that both methods have shortcomings, and the shortcomings are: in the first method, the production cost and process complexity are increased; in the second method, it is impossible to find a matching external resistor in time , even if there is a matching resistor, it increases the wiring with the PLC, which wastes a lot of time and delays the work process

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