A functional safety relay detection method

Abstract

This invention discloses a method for testing functional safety relays, belonging to the field of safety relay technology. The method includes the following steps: determining the pulse frequency for safety relay testing and setting its value; connecting the CPU's pulse input and pulse capture pins to the safety relay; filtering the pulse signal; detecting the closed state of the safety relay upon startup; detecting the open state of the safety relay upon startup; performing a re-check of the safety relay status during system operation; and comparing the re-checked safety relay status with the set safety relay status. This invention provides a method for testing functional safety relays that utilizes the characteristics of safety relays to test relay contacts, using idle contacts of the same safety relay to verify the used contacts, indirectly verifying the relay's operating status. It enables effective and comprehensive testing of safety relays during system operation, improving system safety.

Description

Technical Field

[0001] This invention relates to the field of safety relay technology, and in particular to a method for testing functional safety relays. Background Technology

[0002] A relay is an electrical control device that causes a predetermined step change in the controlled variable in the electrical output circuit when the change in the input quantity (excitation quantity) reaches a specified requirement. It has an interactive relationship between the control system (also known as the input circuit) and the controlled system (also known as the output circuit). It is commonly used in automated control circuits, and is essentially an "automatic switch" that uses a small current to control a large current. Therefore, it plays a role in automatic adjustment, safety protection, and circuit switching in circuits.

[0003] Functional safety systems require the testing of safety relays to prevent dangerous consequences from safety relay malfunctions. A common practice is to test the safety relay contacts by energizing and de-energizing the relay.

[0004] Power-off detection: Input a voltage level signal to the common contact and read the voltage level signal on the normally closed contact side. If the detected voltage level signal is consistent with the input signal to the common contact, the normally closed contact is considered to be working normally.

[0005] Power supply detection: Input a voltage level signal to the common contact side and read the voltage level signal on the normally open contact side. If the detected voltage level signal is consistent with the input signal of the common contact, the normally open contact is considered to be working normally.

[0006] In functional safety systems, safety relays cannot be arbitrarily opened or closed during system operation. Therefore, testing safety relays during system operation is a technical challenge. If relays are not tested during system operation, their operational status cannot be guaranteed, making it difficult to meet the requirements of functional safety systems. Current safety relay testing methods require power-off and power-on operations, thus allowing testing only when the system is powered on, and not during system operation. Summary of the Invention

[0007] The purpose of this invention is to provide a method for testing functional safety relays, which solves the problem that without testing the relays during system operation, the working state of the safety relays cannot be guaranteed, making it difficult to meet the requirements of functional safety systems.

[0008] 2. To achieve the above objectives, the present invention provides a method for testing functional safety relays, comprising the following steps:

[0009] S1. Determine the pulse frequency for the safety relay detection and set its frequency value;

[0010] S2. Connect the CPU's pulse input and pulse capture pins to the safety relay;

[0011] S3. Filter the pulse signal;

[0012] S4. During startup, check the closed state of the safety relay;

[0013] S5. Upon startup, check the safety relay's open state;

[0014] S6. The system performs a back check on the status of the safety relays during operation;

[0015] S7. Compare the safety relay status obtained from the retest with the set safety relay status.

[0016] Preferably, in step S3, if the difference in the number of pulses captured by two adjacent pulses is greater than 1, then the interference signal record is incremented by 1.

[0017] Preferably, in step S4, during the closed state detection, the enable pulse output is performed, the relay is closed, the self-test time of the relay is set, the pulse capture is filtered, and steps S2 and S3 are executed.

[0018] Preferably, in step S4, after the self-test is completed, the pulse output is turned off, and it is determined whether the number of received pulses is equal to the number of sent pulses. If the two are consistent, the relay is considered to be working normally; if the accumulated interference signal exceeds half of the number of sent pulses or the number of sent pulses is not equal to the number of received pulses, the relay is considered to be faulty.

[0019] Preferably, in step S5, when the disconnection status detection is performed, the pulse output is enabled, the relay is disconnected, the self-test time of the relay is set, pulse capture and filtering are performed, and steps 2 and 3 are executed.

[0020] Preferably, in step S5, after the self-test is completed, if the number of received pulses is greater than 0, the relay is considered faulty. If the number of received pulses is not greater than 0, the relay is normal.

[0021] Preferably, in step S6, when the relay status is checked, the pulse input port is always enabled to output a pulse signal, and the CPU performs pulse capture and counting.

[0022] Preferably, in step S6, the relay status is periodically detected. If the number of pulses sent is the same as the number of pulses received, the relay is considered to be closed; if the pulse count is 0, the relay is considered to be open.

[0023] Preferably, in step S7, if the relay status obtained from the re-inspection is consistent with the set relay status, and the interference signal of the relay does not exceed half of the number of transmitted pulses, the relay is considered to be working normally; if the relay status obtained from the re-inspection is inconsistent with the set relay status, or the interference signal of the relay exceeds half of the number of transmitted pulses, the relay is considered to be malfunctioning.

[0024] Therefore, the functional safety relay testing method of the present invention, employing the above-described structure, has the following beneficial effects: it utilizes the characteristics of the safety relay to test the relay contacts, verifies the used contacts using the idle contacts of the same safety relay, and indirectly verifies the relay's operating state. It enables effective and comprehensive testing of the safety relay during system operation, thereby improving system safety.

[0025] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a functional safety relay testing method according to the present invention; Detailed Implementation

[0027] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0029] Example

[0030] like Figure 1 As shown, the present invention provides a method for testing functional safety relays, comprising the following steps:

[0031] S1. Determine the pulse frequency for the safety relay detection, and set the frequency value to 500 Hz;

[0032] S2. Connect the CPU's pulse input and pulse capture pins to the safety relay;

[0033] S3. Filter the pulse signal. If the difference in the number of pulses captured by two adjacent pulses is greater than 1, increment the interference signal record by 1.

[0034] S4. Upon startup, the system checks the closed state of the safety relay, enables pulse output, closes the relay, and sets the relay's self-test time to 20ms. Pulse capture is filtered, and steps S2 and S3 are executed. After the self-test, the pulse output is turned off, and it is determined whether the number of received pulses is equal to the number of transmitted pulses. If they are equal, the relay is considered to be working normally; if the accumulated interference signal exceeds half of the transmitted pulse count or the transmitted pulse count is not equal to the received pulse count, the relay is considered to be faulty.

[0035] S5. Upon startup, the safety relay is checked for open status. During the open status detection, an enable pulse is output, disconnecting the relay. The relay's self-test time is set to 20ms. Pulse capture and filtering are performed, and steps 2 and 3 are executed. After the self-test, if the number of received pulses is greater than 0, the relay is considered faulty. If the number of received pulses is not greater than 0, the relay is normal.

[0036] S6. During system operation, the status of the safety relay is checked. The pulse input port is always enabled to output a pulse signal, and the CPU performs pulse capture and counting. The relay status is periodically checked. If the number of pulses sent and received are the same, the relay is considered to be closed; if the pulse count is 0, the relay is considered to be open.

[0037] S7. Compare the safety relay status obtained from the re-inspection with the set safety relay status. If the re-inspection status is consistent with the set status and the relay interference signal does not exceed half of the number of transmitted pulses, the relay is considered to be working normally. If the re-inspection status is inconsistent with the set status, or the relay interference signal exceeds half of the number of transmitted pulses, the relay is considered to be malfunctioning.

[0038] Therefore, this invention employs the aforementioned functional safety relay testing method, utilizing the characteristics of the safety relay to test the relay contacts. It verifies the used contacts using the idle contacts of the same safety relay, indirectly verifying the relay's operating status. This enables effective and comprehensive testing of the safety relay during system operation, improving system safety.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A functional safety relay detection method, characterized by, The method comprises the following steps: S1, determining the pulse frequency of the safety relay detection and setting the frequency value; S2, connecting the pulse input and pulse capture pin of the CPU with the safety relay; S3, filtering the pulse signal; S4, detecting the closed state of the safety relay at the start; S5, detecting the open state of the safety relay at the start; S6, rechecking the state of the safety relay during the system operation; S7, comparing the state of the safety relay obtained by the rechecking with the set state of the safety relay; In step S3, if the difference between the pulse numbers captured by the adjacent two times of filtering is greater than 1, the interference signal is recorded by 1; In step S6, the pulse input port enables the pulse output signal all the time, and the CPU carries out the pulse capture counting when rechecking the state of the relay; In step S6, the state of the relay is considered as closed if the sent pulse number is consistent with the received pulse number, and the state of the relay is considered as open if the pulse number counting is 0; In step S7, if the result obtained by comparing the state of the relay obtained by the rechecking with the set state of the relay is consistent, and the interference signal of the relay does not exceed half of the sent pulse number, the relay is considered as working normally; if the result obtained by comparing the state of the relay obtained by the rechecking with the set state of the relay is not consistent, or the interference signal of the relay exceeds half of the sent pulse number, the relay is considered as working fault; The idle contact of the same safety relay is used to verify the used contact, and the working state of the relay is indirectly verified.

2. The functional safety relay detection method of claim 1, wherein: In step S4, the pulse output is enabled, the relay is closed, the self-checking time of the relay is set, the pulse capture is filtered, and steps S2 and S3 are executed when detecting the closed state.

3. The functional safety relay detection method of claim 1, wherein: In step S4, after the self-checking is finished, the pulse output is closed, and it is judged whether the received pulse number is equal to the sent pulse number; if yes, the relay is considered as working normally; If the accumulated interference signal exceeds half of the sent pulse number or the sent pulse number is not equal to the received pulse number, the relay is considered as fault.

4. The functional safety relay detection method of claim 1, wherein: In step S5, the pulse output is enabled, the relay is opened, the self-checking time of the relay is set, the pulse capture and filtering are carried out, and steps 2 and 3 are executed when detecting the open state.

5. The functional safety relay detection method of claim 1, wherein: In step S5, after the self-checking is finished, if the received pulse number is greater than 0, the relay is considered as fault; if the received pulse number is not greater than 0, the relay is considered as normal.

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