CN-121978391-A - Signal acquisition circuit and method compatible with dry and wet contacts

CN121978391ACN 121978391 ACN121978391 ACN 121978391ACN-121978391-A

Abstract

The application discloses a signal acquisition circuit and a signal acquisition method compatible with a wet-dry joint, and relates to the technical field of industrial control electronic circuits. The circuit comprises an input terminal for receiving external signals, a relay module comprising a plurality of groups of contacts and a driving circuit, a system power supply, a voltage detection point arranged in an input loop and a processor which is respectively connected with the voltage detection point and the relay module for signal identification and circuit switching control. The application monitors the characteristics of input signals in real time through voltage detection points, and a processor judges the signal types, namely, the signal types are identified as wet contact signals when effective voltage is detected, the relay is controlled to keep a default state to directly collect signals, and the signal types are identified as dry contact signals when the effective voltage is not detected, and the switching state of the relay is controlled to enable a system power supply to be connected into a loop for supplying power. The application realizes the self-adaptive compatible acquisition of the dry and wet contact signals on a single interface, effectively solves the problem of resource waste of the traditional circuit interface, and improves the system integration level and the use convenience.

Inventors

TAN CHENGJI
ZOU JIAXIN
LIU JIE
SHI YIJIN
Shao Deli
JIANG CHUANDONG

Assignees

中国兵器装备集团自动化研究所有限公司

Dates

Publication Date: 20260505
Application Date: 20260206

Claims (10)

1. A signal acquisition circuit compatible with wet and dry contacts, comprising: an input terminal including a first input terminal and a second input terminal connected to each other for receiving an external signal; a relay module comprising a plurality of sets of contacts and a drive circuit; the system power supply is connected to the relay module and used for providing working voltage for the circuit; the voltage detection point is arranged in an input loop between the first input terminal and the relay module and is connected with the processor in a detection way; The processor is respectively connected with the voltage detection point and the driving circuit of the relay module, and monitors the voltage signal in the input loop in real time through the voltage detection point; When the effective voltage is detected, the effective voltage is identified as a wet contact signal, and the relay module is controlled to maintain a default connection state, so that an input signal forms a complete acquisition loop through the first input terminal and the second terminal; When the effective voltage is not detected, the signal is identified as a dry contact point signal, and the relay module is controlled by the driving circuit to switch the contact point state, so that a system power supply is connected into an input loop, and a working voltage is provided for the external dry contact point signal to form an acquisition loop.
2. The signal acquisition circuit compatible with wet and dry contacts of claim 1, wherein the voltage detection point is connected with a voltage acquisition circuit, and the voltage acquisition circuit comprises a voltage dividing resistor and a filter element.
3. The wet and dry contact compatible signal acquisition circuit of claim 2, wherein the voltage divider resistor in the voltage acquisition circuit is configured to convert the input voltage to a safe voltage range recognizable by the processor.
4. The dry and wet contact compatible signal acquisition circuit of claim 1, wherein the default connection state of the relay module is a wet contact signal direct acquisition loop connection state.
5. The signal acquisition circuit compatible with dry and wet contacts of claim 1, wherein the switching state of the relay module is a dry contact signal system power supply loop connection state.
6. The wet and dry contact compatible signal acquisition circuit of claim 1, further comprising an optocoupler isolation element disposed between the input terminal and the processor for signal isolation.
7. A signal acquisition method compatible with wet and dry contacts, applied to the signal acquisition circuit compatible with wet and dry contacts as claimed in any one of claims 1 to 6, comprising the following steps: after the system is powered on, monitoring the voltage at the input terminal through a voltage detection point; Judging the signal type based on the voltage value; if the signal is identified as the wet contact signal, maintaining the default state of the relay module and directly collecting the input signal; if the signal is identified as the dry access point signal, the relay module is controlled to be switched to a switching state, so that the system power supply is connected to the input loop and then the signal is acquired.
8. The method for collecting signals compatible with wet and dry contacts according to claim 7, wherein said determining the signal type based on the voltage value comprises the steps of: analog-to-digital conversion is carried out on the analog voltage of the voltage detection point to obtain a digital voltage value; Performing digital filtering processing on the digital voltage value to obtain a voltage detection result; And judging the signal type of the external signal connected to the input end of the circuit based on the comparison result of the voltage detection value and the preset threshold value.
9. The method of claim 7, wherein the contacts of the relay module are in a default connection state when the system is not powered.
10. The method of claim 7, wherein the voltage monitoring through the voltage detection point is performed automatically each time the system is powered up, and the monitoring duration is a detection period preset by the system.

Description

Signal acquisition circuit and method compatible with dry and wet contacts Technical Field The application relates to an industrial control electronic circuit technology, in particular to a signal acquisition circuit and a signal acquisition method compatible with a dry-wet contact. Background In the field of industrial control, signal acquisition is one of the core links for monitoring equipment status, transmitting control instructions, and the like. Dry contacts and wet contacts are widely used in various automation systems as two common signal types. The dry contact is a passive switch signal, only provides on-off state, does not have power supply, and is controlled by an external mechanical or electronic switch, the wet contact is an active signal, and is provided with voltage (such as direct current 24V) by itself, and the signal is transmitted by forming a loop through the external power supply. Because of the nature difference of the dry and wet contacts, the prior art generally adopts a split design, i.e., separate acquisition circuits are developed for the dry and wet contacts, respectively, to ensure the accuracy and reliability of signal processing. The existing implementation scheme is based on dry-wet contact separation design. The dry contact collecting circuit specially processes passive signals, the design of the dry contact collecting circuit depends on external power supply to drive a collecting circuit, and the wet contact collecting circuit directly collects the signals by utilizing the voltage of the signals without an additional power supply. Such a separate design, while guaranteeing the stability of the respective functions, results in circuit redundancy and interface resource waste. For example, in practical applications, the device needs to reserve two interfaces, i.e., a dry contact and a wet contact, at the same time, which increases hardware complexity and cost. For dry contact acquisition, a common circuit design is shown in fig. 1. When the external dry connection point is closed, current flows through isolating elements such as an optical coupler, and the output end DI_IN generates level change, so that the on-off state is identified. This design is simple and reliable but only applicable to passive signals. For wet contact acquisition, a common circuit is shown in fig. 2. The input signal forms a loop through the ends P and N, the voltage of the signal is utilized to directly drive the acquisition circuit, and the output DI_IN responds along with the change of the input. This design avoids the need for external power, but is not compatible with dry-access signals. In summary, in the prior art, independent collection of the wet and dry contacts is realized through a separate circuit, but the compatibility is lacking, so that the utilization rate of interface resources is low, and the flexibility of the system is insufficient. This provides room for improvement in the integrated design of the present application. . Disclosure of Invention The application provides a signal acquisition circuit compatible with dry and wet contacts, which solves the technical problems of interface resource waste and inconvenient use caused by design separation of the existing dry contact signal acquisition circuit and wet contact acquisition circuit. The application is realized by the following technical scheme: In a first aspect, the present application provides a signal acquisition circuit compatible with wet and dry contacts, comprising: an input terminal including a first input terminal and a second input terminal connected to each other for receiving an external signal; a relay module comprising a plurality of sets of contacts and a drive circuit; the system power supply is connected to the relay module and used for providing working voltage for the circuit; the voltage detection point is arranged in an input loop between the first input terminal and the relay module and is connected with the processor in a detection way; The processor is respectively connected with the voltage detection point and the driving circuit of the relay module, and monitors the voltage signal in the input loop in real time through the voltage detection point; When the effective voltage is detected, the effective voltage is identified as a wet contact signal, and the relay module is controlled to maintain a default connection state, so that an input signal forms a complete acquisition loop through the first input terminal and the second terminal; When the effective voltage is not detected, the signal is identified as a dry contact point signal, and the relay module is controlled by the driving circuit to switch the contact point state, so that a system power supply is connected into an input loop, and a working voltage is provided for the external dry contact point signal to form an acquisition loop. The further optimization scheme is that the voltage detection point is connected with a voltage acquisition circuit,