CN217386200U

CN217386200U - Internal safety chain of PLC

Info

Publication number: CN217386200U
Application number: CN202221363884.3U
Authority: CN
Inventors: 李从飞; 张琦; 朱明�; 刘平卫; 李致远; 倪维东; 赖新芳
Original assignee: Guodian Nanjing Automation Co Ltd
Current assignee: Guodian Nanjing Automation Co Ltd
Priority date: 2022-06-02
Filing date: 2022-06-02
Publication date: 2022-09-06
Anticipated expiration: 2032-06-02

Abstract

The utility model discloses a PLC internal safety chain, which comprises a CPU module, an I/O module, a communication module, a power supply module and a safety chain module, wherein the CPU module is used for outputting a detection fault signal to the safety chain module; the I/O module is used for outputting a fault signal of the I/O module to the safety chain module; the communication module is used for outputting an external communication fault signal to the safety chain module; the power supply module is used for outputting a power supply module fault signal to the safety chain module; and the safety chain module is used for outputting a safety chain signal with a corresponding safety level according to the input detection fault signal, the input I/O module fault signal, the external communication fault signal and the power module fault signal. And each module independently monitors faults, and the monitoring mode is more flexible and comprehensive.

Description

Safety chain in PLC

Technical Field

The utility model relates to an inside safety chain of PLC belongs to safety chain technical field.

Background

Generally, a Programmable Logic Controller (PLC) operates in a distributed manner, and various functional modules such as a CPU module, a power supply module, an I/O module, and a communication module operate independently and are connected in an internal communication manner.

Generally, the output of the fault monitoring function of the PLC having the safety chain function is realized by the CPU module, that is, the CPU module has a certain monitoring function for each module, and can find out the faults of the CPU and some of the modules, and further realize the fault alarm and output through the safety chain module. However, the fault detection function of the CPU module has a dead zone, and the faults of other functional modules cannot be monitored in 100% real time. Meanwhile, each functional module has no independent fault monitoring function, fault detection is not comprehensive, and partial software and hardware faults cannot trigger a safety chain.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome not enough among the prior art, provide an inside safety chain of PLC, each module independent monitoring trouble of CPU module, IO module, communication module, power module and safety chain module, the monitoring mode is more nimble, more comprehensive.

In order to achieve the purpose, the utility model is realized by adopting the following technical scheme:

the utility model discloses a PLC internal safety chain, which comprises a CPU module, an I/O module, a communication module, a power supply module and a safety chain module,

the CPU module is used for outputting a detection fault signal to the safety chain module; the I/O module is used for outputting an I/O module fault signal to the safety chain module; the communication module is used for outputting an external communication fault signal to the safety chain module; the power supply module is used for outputting a power supply module fault signal to the safety chain module;

and the safety chain module is used for outputting a safety chain signal with a corresponding safety level according to the input detection fault signal, the input I/O module fault signal, the external communication fault signal and the power module fault signal.

Further, the detection fault signal comprises a hardware fault signal, a software fault signal and an internal communication fault signal.

Further, the software fault signal is output through a watchdog detection circuit in the CPU module, and a watchdog chip in the watchdog detection circuit is of a TPS3820 type.

Further, the power module fault signals include a 24V power fault signal, a 5V power fault signal, and a 3.3V power fault signal.

Furthermore, the output modes of the CPU module, the I/O module and the power module are all passive joint output.

Further, an optical coupling isolation unit is arranged in the CPU module, the I/O module or the power supply module.

Compared with the prior art, the utility model discloses the beneficial effect who reaches:

the internal safety chain of the PLC of the utility model, the CPU module, the I/O module, the communication module and the power module can independently detect the self fault and output the corresponding fault signal to the safety chain module; the PLC realizes the collection and logic combination of all fault signals through the safety chain module, and outputs safety chain signals of corresponding safety levels aiming at one or more input fault signal types, so that the fault detection is more flexible and comprehensive.

Drawings

FIG. 1 is a schematic diagram of a PLC internal safety chain;

fig. 2 is a fault signal output circuit of an I/O module or a CPU module or a communication module;

FIG. 3 is a software fault signal output circuit;

FIG. 4 is a fault signal output circuit of the power supply module;

FIG. 5 is a fault signal acquisition circuit of the safety chain module;

fig. 6 is a relay output loop of the safety chain module.

Detailed Description

The present invention will be further described with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

Examples

The embodiment discloses a PLC internal safety chain, as shown in FIG. 1, comprising a CPU module, an I/O module, a communication module, a power supply module and a safety chain module,

the CPU module is used for outputting a detection fault signal to the safety chain module; the I/O module is used for outputting a fault signal of the I/O module to the safety chain module; the communication module is used for outputting an external communication fault signal to the safety chain module; the power supply module is used for outputting a power supply module fault signal to the safety chain module;

and the safety chain module is used for outputting a safety chain signal of a corresponding safety level according to the input detection fault signal, the I/O module fault signal, the external communication fault signal and the power module fault signal.

The technical concept of the utility model is that, CPU module, IO module, communication module and each module of power module can all independently detect the trouble of self to output corresponding fault signal to safety chain module, make the fault detection more nimble comprehensive. Meanwhile, the PLC realizes the collection and logic combination of all fault signals through the safety chain module, and outputs safety chain signals of corresponding safety levels according to one or more input fault signal types, namely the safety chain signals of corresponding safety levels can be output according to single output fault signals; or, the configuration processing can be performed according to a plurality of input fault signals, and the output safety chain signal is related to all the input fault signals.

Specifically, the circuit shown in fig. 2 may be applied to a fault signal output circuit of an I/O module, an external communication fault signal output circuit of a communication module, and a hardware fault signal or internal communication fault signal output circuit of a CPU module, where the output mode is passive contact output, and an optical coupling isolation unit K1 is provided between input and output. One input end of the optical coupling isolation unit K1 is connected with a +5V power supply through a resistor R1, and the other input end of the optical coupling isolation unit K1 is connected with an I/O module or a CPU module and used for receiving a fault signal of the I/O module, an external communication fault signal or a hardware fault signal or an internal communication fault signal from the CPU module.

The hardware fault of the CPU module comprises that hardware initialization does not pass or internal memory read-write fails, and the internal communication fault of the CPU module comprises long-time communication interruption or error verification. The internal communication fault signal output by the CPU module refers to a communication fault signal between the CPU module and each sub-module, and the external communication fault signal output by the communication module refers to a communication fault signal between the communication module and an external system.

According to actual requirements, a plurality of I/O modules can be arranged and respectively used for accessing digital quantity input, digital quantity output, analog quantity input, analog quantity output, temperature monitoring, frequency measurement and the like.

The circuit shown in fig. 3 may be applied to a software failure signal output circuit of a CPU module. Software trouble output circuit adopts watchdog detection circuitry to realize software monitoring function, and when the procedure normally operated, regularly got the contrary output WDIO signal, when software ran off or the procedure ran to death, the WDIO signal will normally not get the contrary, and the KCJ signal of watchdog chip TPS3820 output will shift, and the passive contact of passing through optical coupling isolation unit K1 output will shift this moment.

The circuit shown in fig. 4 can be applied to a fault signal output circuit of a power module, can monitor a 24V power supply, a 5V power supply and a 3.3V power supply on a power panel, when any power supply loses power, the power supply is displaced through a passive contact output by the optical coupling isolation unit K1, the 24V power supply is an input power supply of the power module, and an electrical isolation unit K2 is arranged between the 24V power supply and the 5V power supply and between the 24V power supply and the 3.3V power supply.

The circuit shown in fig. 5 is a fault signal acquisition circuit of the safety chain module, and the passive contacts output by the I/O module, the CPU module and the power supply module are connected to the safety chain module, and the safety chain module provides 24V power.

The circuit shown in fig. 6 is a relay output loop of a safety chain module, the safety chain module carries out logic combination by detecting passive idle contacts output by other modules, and the safety chain module drives a magnetic latching relay to realize safety output through an optical coupler.

In summary, each of the CPU module, the I/O module, the communication module and the power module can independently detect its own fault and output a corresponding fault signal to the safety chain module, so that the fault detection is more flexible and comprehensive. Different modules can output different types of fault signals, for example, a CPU module can output different types of detection fault signals such as a hardware fault signal, a software fault signal and a communication fault signal. All fault signals are input into the safety chain module, the PLC acquires and logically combines all fault signals through the safety chain module, and a final result is output to control the opening and closing state of the relay. The relays herein refer to the generic term of relays controlled by the safety chain module and not to a single relay.

It is emphasized that each module independently monitors the fault, and the monitoring mode is more flexible and comprehensive; different modules can output different types of fault signals, the different types of fault signals are input into the safety chain module, and safety chain signals with different safety levels are output through the safety chain module. Meanwhile, the safety chain module can also perform configuration processing according to a plurality of input fault signals, output safety chain signals with corresponding safety levels, and the safety chain signals are related to all the input fault signals.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be considered as the protection scope of the present invention.

Claims

1. A PLC internal safety chain is characterized by comprising a CPU module, an I/O module, a communication module, a power supply module and a safety chain module,

2. The PLC internal safety chain according to claim 1, wherein the detection fault signal includes a hardware fault signal, a software fault signal, and an internal communication fault signal.

3. The PLC internal safety chain according to claim 2, wherein the software fault signal is output through a watchdog detection circuit in the CPU module, and the model of a watchdog chip in the watchdog detection circuit is TPS 3820.

4. The PLC internal safety chain according to claim 1, wherein the power module fault signals include a 24V power fault signal, a 5V power fault signal, and a 3.3V power fault signal.

5. The PLC internal safety chain according to claim 1, wherein the output modes of the CPU module, the I/O module and the power module are all passive contact outputs.

6. The PLC internal safety chain according to claim 1, wherein an optical coupling isolation unit is further arranged in the CPU module, the I/O module or the power supply module.