Emergency shut-off control system for target fluid transmission

Abstract

Embodiments of the present disclosure relate to an emergency cut-off control system for target fluid transmission. The emergency cut-off control system includes: a control unit of a proximal device, which outputs a proximal current to an isolation interlock unit and receives the proximal current returned via the isolation interlock unit, and is configured to stop outputting the proximal current in response to detecting that the returned proximal current is greater than a first predetermined current; the isolation interlock unit is configured to disconnect the first return path when the remote current is less than a second predetermined current, and disconnect the second return path when the proximal current is less than a third predetermined current; and a control unit of a remote device, which is configured to output a remote current to the isolation interlock unit and receive the remote current returned via the second return path of the isolation interlock unit. When the returned current is too large, the emergency cut-off control system can promptly cut off the current loop to ensure safety.

Description

Technical Field

[0001] Embodiments of the present disclosure relate generally to the field of emergency shutdown (ESD), and more particularly to an emergency shutdown control system for target fluid delivery. Background Art

[0002] For example, if a dangerous situation occurs during the transfer of liquefied natural gas (LNG) from ship to shore, the transfer must be stopped immediately to ensure safety. Therefore, if a dangerous situation occurs on the ship, the shore-side equipment must be notified to stop the transfer operation; and if a dangerous situation occurs on shore, the ship-side equipment must be notified to stop the transfer operation.

[0003] Current emergency shutdown control devices rely solely on signals from ship-side or shore-side equipment to implement the shutdown operation. They cannot respond promptly to abnormalities in other components, such as the control equipment, posing a safety hazard. Summary of the Invention

[0004] In response to the above problems, the present disclosure provides an emergency cut-off control system for target fluid transmission. When the backflow current is too large, the emergency cut-off control system can cut off the current loop in time to ensure safety.

[0005] According to one aspect of the present disclosure, an emergency shut-off control system for target fluid transmission is provided. The target fluid is configured to be transmitted between a proximal device and a distal device. The emergency shut-off control system includes: a control unit of the proximal device, configured to output a proximal current to an isolation interlock unit and receive the proximal current returned via the isolation interlock unit, and configured to stop outputting the proximal current in response to detecting that the returned proximal current is greater than a first predetermined current; the isolation interlock unit, including: a first return path for returning the proximal current to the control unit of the proximal device, and a second return path for returning the distal current to the control unit of the distal device, the isolation interlock unit being configured to disconnect the first return path when the distal current is less than the second predetermined current, and disconnect the second return path when the proximal current is less than a third predetermined current; and a control unit of the distal device, configured to output the distal current to the isolation interlock unit and receive the distal current returned via the second return path of the isolation interlock unit.

[0006] In some embodiments, the control unit of the proximal device is further configured to: output a proximal current having a fourth predetermined current value in response to detecting that an emergency shut-off signal from the proximal device indicates a normal state and detecting that the recirculated proximal current is less than or equal to a first predetermined current; and in response to detecting that the emergency shut-off signal indicates a normal state and detecting that the recirculated proximal current is greater than the first predetermined current, first stop outputting the proximal current, and enable the first return path and the second return path to be connected within a first predetermined time interval and output a proximal current having a fifth predetermined current value, wherein the fourth predetermined current value is greater than the fifth predetermined current value.

[0007] In some embodiments, the control unit of the proximal device is further configured to: the control unit of the proximal device is further configured to: output a cut-off control signal to the proximal device in response to detecting that the time for which the refluxed proximal current is less than a predetermined lower limit current is greater than a second predetermined time, and the second predetermined time interval is greater than the first predetermined time interval.

[0008] In some embodiments, the control unit of the proximal device is further configured to stop outputting the proximal current in response to detecting that the emergency shutoff signal indicates a fault state.

[0009] In some embodiments, the control unit of the proximal device includes: a first branch, connected in parallel with the second branch, configured to output a proximal current having a fourth predetermined current value; and a second branch, configured to output a proximal current having a fifth predetermined current value; the control unit of the proximal device is further configured to: in response to detecting that the emergency shut-off signal indicates a fault state, disconnect the first branch and the second branch; in response to detecting that the emergency shut-off signal indicates a normal state and detecting that the returned proximal current is less than or equal to the first predetermined current, turn on the first branch and disconnect the second branch; and in response to detecting that the emergency shut-off signal indicates a normal state and detecting that the returned proximal current is greater than the first predetermined current, first disconnect the first branch and the second branch, then turn on the second branch, and connect the first return path and the second return path.

[0010] In some embodiments, the control unit of the proximal device further includes: a sampling resistor configured to receive the recirculated proximal current so as to output a sampling voltage; a first comparator, wherein the non-inverting input terminal of the first comparator is configured to receive the sampling voltage, and the inverting input terminal of the first comparator is configured to receive a signal having a first predetermined voltage, the first predetermined voltage being related to the first predetermined current; and a first MOS transistor, wherein the gate of the first MOS transistor is electrically connected to the output terminal of the first comparator, the source of the first MOS transistor is grounded, and the drain of the first MOS transistor is electrically connected to the control terminals of the first branch and the second branch.

[0011] In some embodiments, the control unit of the proximal device further includes: a second comparator, one input end of the second comparator being configured to receive a sampling voltage, and another input end of the second comparator being configured to receive a signal having a second predetermined voltage; and a control device, the control device being configured to output a cut-off control signal to the proximal device in response to detecting that the output end of the second comparator is in the first state for a time period greater than a first predetermined time, and to output a control signal to the control ends of the first branch and the second branch in response to detecting that the emergency cut-off signal from the proximal device indicates a fault state so that the first branch and the second branch are disconnected, the first state corresponding to the proximal current flowing back being less than a predetermined lower limit current.

[0012] In some embodiments, the emergency shut-off control system further includes: an internal loop switch unit configured to be turned on in response to detecting that the test signal is in a valid state, so as to provide a test path for the proximal current to flow back to the control unit of the proximal device; the control unit of the proximal device is also configured to disconnect from the isolation interlock unit in the test mode, and to make the test signal in a valid state, and to generate a proximal current.

[0013] In some embodiments, the isolation interlock unit includes a first photocoupler and a second photocoupler, the first return path includes at least the light source of the first photocoupler and the light receiver of the second photocoupler, the light source of the first photocoupler and the light receiver of the second photocoupler are connected in series, and the second return path includes at least the light source of the second photocoupler and the light receiver of the first photocoupler, the light source of the second photocoupler and the light receiver of the first photocoupler are connected in series.

[0014] In some embodiments, the isolation interlock unit further includes: a first reset switch, one end of the first reset switch is electrically connected to one end of the photoreceiver of the first optocoupler, and the other end of the first reset switch is electrically connected to the other end of the photoreceiver of the first optocoupler; and a second reset switch, one end of the second reset switch is electrically connected to one end of the photoreceiver of the second optocoupler, and the other end of the second reset switch is electrically connected to the other end of the photoreceiver of the second optocoupler; the first reset switch and the second reset switch are configured to be turned on in response to detecting that the reset signal is in a valid state.

[0015] In some embodiments, the control unit of the remote device is further configured to stop outputting the remote current to the isolation interlock unit in response to at least one of the following: detecting that an emergency shut-off signal from the remote device indicates a fault state; and detecting that the returned remote current is greater than a sixth predetermined current; the proximal end is one of the source end and the destination end, and the proximal end is the other of the source end and the destination end.

[0016] In some embodiments, the control unit of the proximal device further includes: a first safety barrier, the input end of the first safety barrier being electrically connected to the output ends of the first branch and the second branch, and the output end of the first safety barrier being configured to output the proximal current; and a second safety barrier, the input end of the second safety barrier being configured to receive the returned proximal current, and the output end of the second safety barrier being electrically connected to the sampling resistor.

[0017] According to an embodiment of the present disclosure, the control unit of the proximal device of the emergency shutoff control system is configured to output a proximal current to an isolation interlock unit and receive the proximal current recirculated through the isolation interlock unit. Furthermore, the control unit is configured to stop outputting the proximal current in response to detecting that the recirculated proximal current exceeds a first predetermined current. The isolation interlock unit includes: a first return path for returning the proximal current to the control unit of the proximal device, and a second return path for returning the remote current to the control unit of the remote device. The isolation interlock unit is configured to disconnect the first return path when the remote current is less than a second predetermined current, and disconnect the second return path when the proximal current is less than a third predetermined current. Furthermore, the control unit of the remote device is configured to output the remote current to the isolation interlock unit and receive the remote current recirculated through the isolation interlock unit. Therefore, when the recirculated proximal current is excessive (e.g., greater than the first predetermined current), the emergency shutoff control system can promptly disconnect the current loop, preventing fire and other dangerous situations caused by the excessive current, thereby ensuring safety.

[0018] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements.

[0020] Figure 1 A block diagram of an emergency shutoff control system for target fluid transmission according to an embodiment of the present disclosure is shown.

[0021] Figure 2 A schematic structural diagram of a control unit of a proximal device according to an embodiment of the present disclosure is shown.

[0022] Figure 3 A schematic structural diagram of an isolation interlocking unit according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0023] The following description of exemplary embodiments of the present disclosure is made in conjunction with the accompanying drawings, including various details of the embodiments of the present disclosure to facilitate understanding. These details should be considered as merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. Similarly, for the sake of clarity and conciseness, descriptions of well-known functions and structures are omitted in the following description.

[0024] As used herein, the term "including" and its variations represent open inclusion, i.e., "including but not limited to." Unless otherwise stated, the term "or" means "and / or." The term "based on" means "based at least in part on." The terms "an example embodiment" and "an embodiment" mean "at least one example embodiment." The term "another embodiment" means "at least one additional embodiment." The terms "first," "second," etc. may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0025] As previously described, current emergency shutdown control devices rely solely on signals from ship-side or shore-side equipment to implement shutdown operations. This prevents timely responses to abnormalities in other components, such as the control equipment, posing a safety hazard.

[0026] In order to at least partially solve one or more of the above-mentioned problems and other potential problems, an example embodiment of the present disclosure proposes an emergency shut-off control system for target fluid transmission. The target fluid is configured to be transmitted between a proximal device and a remote device. The control unit of the proximal device of the emergency shut-off control system is configured to output a proximal current to an isolation interlock unit and receive the proximal current returned via the isolation interlock unit, and is configured to stop outputting the proximal current in response to detecting that the returned proximal current is greater than a first predetermined current. The isolation interlock unit includes: a first return path for returning the proximal current to the control unit of the proximal device, and a second return path for returning the remote current to the control unit of the remote device, the isolation interlock unit being configured to disconnect the first return path when the remote current is less than the second predetermined current, and disconnect the second return path when the proximal current is less than a third predetermined current; and a control unit of the remote device being configured to output the remote current to the isolation interlock unit and receive the remote current returned via the isolation interlock unit. Therefore, when the proximal current flowing back is too large (for example, greater than the first predetermined current), the emergency cut-off control system can cut off the current loop in time to avoid fire and other dangerous situations caused by the excessive current, so as to ensure safety.

[0027] Figure 1FIG. 1 is a block diagram of an emergency shutoff control system 100 for target fluid transmission according to an embodiment of the present disclosure. Figure 2 A schematic structural diagram of the control unit 102 of the proximal device according to an embodiment of the present disclosure is shown. Figure 3 A schematic diagram of the structure of the isolation interlock unit 104 in an embodiment of the present disclosure is shown. The target fluid is configured to be transferred between a proximal device and a remote device. It should be understood that during the transfer between the proximal and remote devices, the target fluid will pass through a hazardous area (or "explosion-proof zone") located between the proximal and remote devices. Explosion-proof measures are required for this hazardous area. The emergency shutoff control system 100, for example, includes a proximal device control unit 102, an isolation interlock unit 104, and a remote device control unit 106. The proximal device control unit 102 can, for example, be communicatively connected to the proximal device 201 to receive emergency shutoff signals from the proximal device 201 and send shutoff control signals to the proximal device 201. The remote device control unit 106 can, for example, be communicatively connected to the remote device 203 to receive emergency shutoff signals from the remote device 203 and send shutoff control signals to the remote device 203. The proximal device 201 is located at the proximal end, and the remote device 203 is located at the remote end. The target fluid is configured to be transmitted between a near-end device 201 and a far-end device 203. The near-end is one of the source and destination ends, and the near-end is the other of the source and destination ends. In the scenario of liquefied natural gas transmission between a ship and a shore terminal, the far-end and destination end are the ship end and the shore end, the near-end is, for example, one of the ship or the shore terminal, and the far-end is, for example, the other of the ship or the shore terminal. In the scenario of liquefied natural gas transmission between ships, the far-end and destination end are the first ship and the second ship, the near-end is, for example, one of the first ship (e.g., the source ship) or the second ship (e.g., the destination ship), and the far-end is, for example, the other of the first ship (e.g., the source ship) or the second ship (e.g., the destination ship). The target fluid is, for example, a liquid such as liquefied natural gas. When the cut-off control signal indicates a cut-off operation, the near-end device 201 stops the relevant transmission operation to ensure safety.

[0028] During the transmission of the target fluid, taking the proximal device 201 as an example, if the proximal device 201 operates normally, the proximal device 201 generates an emergency shutoff signal indicating a normal state (e.g., a high-level state) and transmits it to the proximal device control unit 102. If the proximal device 201 operates abnormally (or "failure"), the proximal device 201 generates an emergency shutoff signal indicating a failure state (e.g., a low-level state) and transmits it to the proximal device control unit 102. The proximal device 201 can perform a transmission operation for the target fluid. For example, the proximal device 201 is equipped with detection devices for temperature, pressure, liquid level, flow rate, etc. If the values ​​detected by the relevant detection devices deviate from a predetermined safety range, the proximal device 201 determines that the operation is abnormal and generates an emergency shutoff signal indicating a failure state.

[0029] Similarly, taking remote device 203 as an example, if remote device 203 is operating normally, remote device 203 generates an emergency shutoff signal indicating a normal state (e.g., a high-level state) and transmits it to remote device control unit 106. If remote device 203 is operating abnormally (or "faulty"), remote device 203 generates an emergency shutoff signal indicating a faulty state (e.g., a low-level state) and transmits it to remote device control unit 106. Remote device 203 can perform a transmission operation on a target fluid. For example, remote device 203 may be equipped with detection devices for temperature, pressure, liquid level, flow rate, etc. If the values ​​detected by the relevant detection devices deviate from a predetermined safety range, remote device 203 determines that it is operating abnormally and generates an emergency shutoff signal indicating a faulty state.

[0030] It should be understood that the application scenarios of the emergency shutoff control system 100 are not limited to emergency shutoff during the loading and unloading of target fluids, but also include emergency shutoff protection for various equipment during normal navigation and docking of a ship. The emergency shutoff signals generated by the local device 201 and the remote device 203 include, for example, emergency shutoff signals for transmission pumps, emergency shutoff signals for high liquid level alarms, emergency shutoff signals for refueling emergency stops, and emergency shutoff signals for factors such as temperature, pressure, liquid level, and ship's lateral and longitudinal parameters exceeding limits.

[0031] The control unit 102 of the near-end device is communicatively connected to the near-end device 201 and electrically connected to the isolation interlock unit 104. The control unit 102 of the near-end device is configured to output a near-end current to the isolation interlock unit 104 and receive the near-end current flowing back through the isolation interlock unit 104, and is configured to stop outputting the near-end current in response to detecting that the flowing back near-end current is greater than a first predetermined current.

[0032] The control unit 102 of the proximal device includes at least a proximal output terminal 121 and a proximal input terminal 122. The proximal output terminal 121 is configured to output a proximal current to the isolation interlock unit 104. The proximal input terminal 122 is configured to receive the proximal current recirculated via the first recirculation path of the isolation interlock unit 104. The control unit 102 of the proximal device is further configured to stop outputting the proximal current to the isolation interlock unit 104 in response to at least one of the following: detecting that an emergency shutdown signal from the proximal device 201 indicates a fault state, and detecting that the recirculated proximal current is greater than a first predetermined current.

[0033] For example, the control unit 102 of the proximal device is further configured to: in response to detecting that the emergency shutoff signal from the proximal device indicates a normal state and that the recirculated proximal current is less than or equal to a first predetermined current, output a proximal current having a fourth predetermined current value; and in response to detecting that the emergency shutoff signal indicates a normal state and that the recirculated proximal current is greater than the first predetermined current, first stop outputting the proximal current, and then, within a first predetermined time interval, connect the first and second recirculation paths and output a proximal current having a fifth predetermined current value, where the fourth predetermined current value is greater than the fifth predetermined current value. In other words, in the event that the recirculated proximal current is excessive (e.g., greater than the first predetermined current), the emergency shutoff control system 100 may first shut off the output proximal current for protection purposes and to avoid risks caused by excessive current. Then, within the first predetermined time interval after cessation of the proximal current output, the closed circuit is restored, and the output is resumed at a lower current. The first predetermined time interval can be appropriately set based on specific circumstances, for example, 100 milliseconds. The first predetermined current can also be appropriately set based on specific needs. In some embodiments, the first predetermined current is, for example, 1.5 times the rated value of the proximal current.

[0034] The control unit of the proximal device is further configured to output a shutdown control signal to the proximal device in response to detecting that the proximal current flowing back is less than a predetermined lower current limit for a duration greater than a second predetermined time, where the second predetermined time interval is greater than the first predetermined time interval. That is, in some embodiments, if the closed circuit of the proximal device's control unit is disconnected, resulting in the cessation of proximal current output, for example, due to excessive proximal current flowing back (e.g., greater than the first predetermined current), the emergency shutdown control system 100 can proactively restore the closed circuit within a reasonable predetermined time. Thus, the duration of the proximal current flowing back is less than the predetermined lower current limit is less than or equal to the second predetermined time. To avoid confusion or erroneous operation of the proximal device 201 (or remote device 203), this situation can be distinguished from an emergency shutdown scenario in which the proximal device 201 (or remote device 203) generates an emergency shutdown signal indicating a fault condition. For example, in this situation, the control unit 102 of the near-end device does not generate a disconnection control signal. Therefore, the near-end device 201 does not deem that an emergency disconnection event has occurred at the remote device 203 and does not cease related transmission operations, thereby avoiding unnecessary shutdowns and malfunctions. However, if the returned near-end current remains below a predetermined lower current limit for a period exceeding a second predetermined time, it is considered that an emergency disconnection event has occurred at the remote device 203 (or near-end device 201) (outputting an emergency disconnection signal indicating a fault condition). Consequently, the control unit 102 of the near-end device outputs a disconnection control signal to the end device 201, instructing the end device 201 to implement a disconnection or shutdown operation, thereby ceasing related transmission operations.

[0035] The control unit 102 of the proximal device, for example, includes a control device 123, a first switch unit K1, a first branch, and a second branch. The first branch is connected in parallel with the second branch. The first branch is configured to output a proximal current having a fourth predetermined current value. The second branch is configured to output a proximal current having a fifth predetermined current value. The control unit of the proximal device is further configured to: disconnect the first branch and the second branch in response to detecting that the emergency shutoff signal indicates a fault state; connect the first branch and disconnect the second branch in response to detecting that the emergency shutoff signal indicates a normal state and that the recirculated proximal current is less than or equal to the first predetermined current; and disconnect the first branch and the second branch first and then connect the second branch in response to detecting that the emergency shutoff signal indicates a normal state and that the recirculated proximal current is greater than the first predetermined current.

[0036] One end of the first switch unit K1 is electrically connected to the power supply terminal VCC, and the other end of the first switch unit K1 is electrically connected to the first branch and the second branch, respectively. The first branch and the second branch are connected in parallel, and the first branch includes at least a first resistor R1. The second branch includes at least a second resistor R2. The resistance of the first resistor R1 is less than the resistance of the second resistor R2. The output ends of the first branch and the second branch are electrically connected to the proximal output terminal 121.

[0037] The control unit 102 of the proximal device is further configured to: in response to detecting that the emergency shutoff signal indicates a fault state, disconnect the first switch unit K1; in response to detecting that the emergency shutoff signal indicates a normal state and detecting that the recirculated proximal current is less than or equal to a first predetermined current, connect the first switch unit K1 and the first branch to output a proximal current having a fourth predetermined current; and in response to detecting that the emergency shutoff signal indicates a normal state and detecting that the recirculated proximal current is greater than the first predetermined current, first disconnect the first switch unit K1 and then connect the first switch unit K1 and the second branch to output a proximal current having a fifth predetermined current. It should be understood that the fourth predetermined current is greater than the fifth predetermined current.

[0038] In some embodiments, the first switch unit K1 is implemented, for example, using a photocoupler. The positive electrode of the light source (e.g., a light-emitting diode) of the first switch unit K1 serves as the control terminal of the first switch unit K1, and the negative electrode of the light source (e.g., a light-emitting diode) of the first switch unit K1 is grounded. One end of the light receiver of the first switch unit K1 serves as one end of the first switch unit K1 and is electrically connected to the power supply terminal VCC. The other end of the light receiver of the first switch unit K1 serves as the other end of the first switch unit K1 and is electrically connected to the first branch and the second branch. In some embodiments, the other end of the light receiver of the first switch unit K1 is electrically connected to, for example, a two-way switch KS, which is electrically connected to the first branch and the second branch. The two-way switch KS is controlled, for example, by a strobe signal to connect one of the first branch and the second branch to the first switch unit K1. The strobe signal can be generated, for example, by the control device 123. For example, the first input terminal I1 of the control device 123 is electrically connected to the output terminal of the first comparator U1 (via the fourth resistor R4) so ​​as to generate a gating signal based on the signal output by the first comparator U1. For example, when the signal output by the first comparator U1 indicates that the sampled voltage output by the sampling resistor RS is higher than a first predetermined voltage (i.e., the proximal current flowing back is greater than the first predetermined current), the control device 123 generates a gating signal for controlling the second branch to be conductive. For example, the gating signal controls the one-out-of-two switch KS, thereby connecting the second branch to the first switch unit K1 and disconnecting the first branch from the first switch unit K1. When the signal output from the first comparator U1 indicates that the sampled voltage output by the sampling resistor RS is less than or equal to a first predetermined voltage (i.e., the proximal current flowing back is less than or equal to the first predetermined current), the control device 123 generates a gating signal for controlling the first branch to be conductive. For example, the gating signal controls the two-choose-one switch KS, thereby connecting the first branch to the first switch unit K1 and disconnecting the second branch from the first switch unit K1. The control device 123 may include, for example, a PLC (programmable logic controller), a DCS (distributed control system), an MCU (microcontroller), an FPGA (field programmable gate array), etc.

[0039] The current output by the first branch is related to the resistance value of the first resistor R1. Specifically, the current output by the first branch is constrained by the voltage of the power supply terminal VCC, the on-state voltage drop of the first switch unit K1, and the resistance value of the first resistor R1. For example, the current output by the first branch is the ratio of the difference between the voltage of the power supply terminal VCC and the on-state voltage drop of the first switch unit K1 to the resistance value of the first resistor R1. For example, by appropriately setting the resistance value of the first resistor R1, the current output by the first branch can conform to the fourth predetermined current.

[0040] Similarly, the current output by the second branch is related to the resistance value of the second resistor R2. Specifically, the current output by the second branch is constrained by the voltage of the power supply terminal VCC, the on-state voltage drop of the first switch unit K1, and the resistance value of the second resistor R2. For example, the current output by the second branch is the ratio of the difference between the voltage of the power supply terminal VCC and the on-state voltage drop of the first switch unit K1 to the resistance value of the second resistor R2. For example, by appropriately setting the resistance value of the second resistor R2, the current output by the second branch can be made to conform to the fifth predetermined current.

[0041] The resistance of the first resistor R1 is smaller than the resistance of the second resistor R2 , so the fourth predetermined current is greater than the fifth predetermined current.

[0042] The control unit of the proximal device also includes a first comparator U1 and a first MOS transistor Q1. The non-inverting input of the first comparator U1 is configured to receive a sampled voltage. For example, the non-inverting input of the first comparator U1 is electrically connected to one end of the sampling resistor RS. The inverting input of the first comparator U1 is configured to receive a signal VH having a first predetermined voltage, which is related to a first predetermined current. For example, the first predetermined voltage is the product of the first predetermined current and the resistance value of the sampling resistor RS. The gate of the first MOS transistor Q1 is electrically connected to the output of the first comparator U1, the source of the first MOS transistor Q1 is grounded GND, and the drain of the first MOS transistor Q1 is electrically connected to the control terminals of the first branch and the second branch. For example, the drain of the first MOS transistor Q1 is electrically connected to the control terminal of the first control unit K1 to control whether the first control unit K1 is turned on or off.

[0043] The control device 123 is further configured to, in response to detecting that the emergency shutoff signal from the near-end device 201 indicates a fault condition, cause the control unit 102 of the near-end device to cease outputting the near-end current. The first output terminal O1 of the control device 123 is electrically connected to the control terminal of the first switch unit K1 (e.g., the positive electrode of the light source of the first switch unit K1). For example, the first output terminal O1 of the control device 123 is electrically connected to the control terminal of the first switch unit K1 via a third resistor R3. It should be understood that the third resistor R3 is a current-limiting resistor. The control device 123 outputs a first switch control signal for controlling the first switch unit K1 via its first output terminal O1.

[0044] The control unit 102 of the proximal device also includes a first safety barrier 124 and a second safety barrier 125. The input of the first safety barrier 124 is electrically connected to the outputs of the first branch and the second branch. The output of the first safety barrier 124 is configured to be electrically connected to the proximal output terminal 121 to output the proximal current. The input of the second safety barrier 125 is configured to be electrically connected to the proximal input terminal 122 to receive the recirculating proximal current. The output of the second safety barrier is electrically connected to one end of the sampling resistor RS to transmit the recirculating proximal current to the sampling resistor RS. For example, the first safety barrier 124 and the second safety barrier 125 output an intrinsically safe current of 4 to 20 mA (milliamperes).

[0045] The control unit 102 of the proximal device, for example, also includes a second comparator U2. One end of the sampling resistor RS is electrically connected to the proximal input terminal 122, and the other end of the sampling resistor RS is grounded to GND. One input of the second comparator U2 is configured to receive a sampled voltage, and the other input of the second comparator U2 is configured to receive a signal having a second predetermined voltage. For example, the non-inverting input of the second comparator U2 is electrically connected to one end of the sampling resistor RS, and the inverting input of the second comparator U2 is configured to receive a signal having a second predetermined voltage VL. The control device 123 is configured to output a cutoff control signal in response to detecting that the output of the second comparator U2 is in the first state. When the voltage output by the sampling resistor RS is higher than the second predetermined voltage, the output of the second comparator U2 outputs a high-level signal. When the voltage output by the sampling resistor RS is lower than the second predetermined voltage, the output of the second comparator U2 outputs a low-level signal. The second predetermined voltage is set sufficiently low such that when the output of the second comparator U2 outputs a low-level signal, it can be assumed that substantially no current (less than a predetermined lower current limit) is flowing through the sampling resistor RS. In other words, when no current flows through the sampling resistor RS, that is, when the proximal current received by the proximal input terminal 122 and flowing back through the first return path of the isolation interlock unit 104 is zero, the output terminal of the second comparator U2 outputs a low-level signal. In this case, the low-level state of the output signal of the output terminal of the second comparator U2 (e.g., the "first state" corresponding to the output signal of the output terminal of the second comparator U2) can indicate that the recirculated proximal current is less than a predetermined lower current limit. In other words, the "first state" corresponding to the output signal of the output terminal of the second comparator U2 corresponds to the recirculated proximal current being less than the predetermined lower current limit.

[0046] It is worth noting that the reasons why the output signal of the output terminal of the second comparator U2 is in the "first state", or in other words, the proximal current flowing back is less than the predetermined lower limit current, may include: (1) an emergency cut-off event occurs in the remote device 203 and an emergency cut-off signal representing a fault state is output; (2) an emergency cut-off event occurs in the proximal device 201 and an emergency cut-off signal representing a fault state is output; (3) the proximal current flowing back is greater than the first predetermined current, causing the control unit of the proximal device to stop outputting the proximal current; (4) the remote current flowing back is greater than the sixth predetermined current, causing the control unit of the remote device to stop outputting the remote current.

[0047] In some embodiments, for the above-mentioned reason (3) (reason (4) is similar thereto), for example, the closed circuit of the control unit of the proximal device is disconnected due to the excessive proximal current (for example, greater than the first predetermined current) and thus the output of the proximal current is stopped. The emergency cut-off control system 100 can actively restore the closed circuit within a reasonable predetermined time, and the proximal current that is flowing back is restored to a value greater than or equal to the predetermined lower limit current. Accordingly, the output signal of the output terminal of the second comparator U2 is converted to a "second state" (for example, a high level state) that is different from the "first state". Thus, the time during which the proximal current that is flowing back is less than the predetermined lower limit current is less than or equal to the second predetermined time. In order to avoid confusion, or to avoid causing malfunction of the proximal device 201 (or the remote device 203), this situation can be distinguished from the emergency cut-off situation in which the proximal device 201 (or the remote device 203) generates an emergency cut-off signal representing a fault state. For example, for reason (3), the control unit 102 of the near-end device does not generate a disconnection control signal. Therefore, the near-end device 201 does not think that an emergency disconnection event has occurred in the remote device 203 and does not stop related transmission operations, thereby avoiding unnecessary shutdowns and erroneous operations.

[0048] As for reason (1) (reason (2) is similar), the time required to eliminate the emergency disconnection event is longer (greater than the second predetermined time), so the time during which the proximal current flowing back is less than the predetermined lower limit current (or the output signal of the output terminal of the second comparator U2 is in the "first state") is greater than the second predetermined time. Therefore, when the proximal current flowing back is less than the predetermined lower limit current (or the output signal of the output terminal of the second comparator U2 is in the "first state") is greater than the second predetermined time, it is considered that the remote device 203 (or the proximal device 201) has an emergency disconnection event (outputting an emergency disconnection signal indicating a fault state), and then the control unit 102 of the proximal device outputs a disconnection control signal to the end device 201 to notify the end device 201 to perform a disconnection or shutdown operation and stop related transmission operations.

[0049] It is worth noting that, in some embodiments, the inverting input terminal of the second comparator U2 is configured to receive a sampling voltage, and the non-inverting input terminal of the second comparator U2 is configured to receive a signal having a second predetermined voltage, then the polarity of the signal outputted by the output terminal of the second comparator U2 is opposite to the aforementioned one.

[0050] The isolation interlock unit 104 is configured to provide at least a first return path connecting the proximal output terminal 121 and the proximal input terminal 122, and is electrically connected to the remote device's control unit 106 to receive a remote current from the remote device's control unit 106. The isolation interlock unit 104 is also configured to disconnect the first return path in response to determining that the remote current is less than a second predetermined current. It should be understood that when the first return path connecting the proximal output terminal 121 and the proximal input terminal 122 is disconnected, the proximal current received by the proximal input terminal 122 of the proximal device's control unit 102 via the first return path of the isolation interlock unit is zero.

[0051] The isolation interlock unit 104 is further configured to provide a second return path connecting the remote output terminal 161 and the remote input terminal 162 , and disconnect the second return path in response to determining that the proximal current is less than a third predetermined current.

[0052] In some embodiments, the isolation interlock unit 104 includes a first photocoupler 141 and a second photocoupler 142. It should be understood that the photocoupler includes a light source and a light receiver. When the light source is not supplied with current and does not emit light, the light receiver is not light-sensitive and is in an off state. When the light source is supplied with current and emits light, the light receiver is light-sensitive and turns on. The light source is a light-emitting diode, and the light receiver is, for example, a photoresistor, a photodiode, a phototransistor, a photothyristor, etc. The first photocoupler 141 includes, for example, a first light source 1411 and a first light receiver 1412. The second photocoupler 142 includes, for example, a second light source 1421 and a second light receiver 1422.

[0053] The first return path includes at least the light source of the first photocoupler 141 (for example, the first light source 1411) and the light receiver of the second photocoupler 142 (for example, the second light receiver 1422), wherein the light source of the first photocoupler 141 and the light receiver of the second photocoupler 142 are connected in series. The second return path includes at least the light source of the second photocoupler 142 (for example, the second light source 1421) and the light receiver of the first photocoupler 141 (for example, the first light receiver 1412), and the light source of the second photocoupler 142 and the light receiver of the first photocoupler 141 are connected in series.

[0054] The first return path, for example, also includes a first light-emitting diode (LED1), which is connected in series with the light source of the first photocoupler 141 and the light receiver of the second photocoupler 142. It should be understood that when the first return path is conductive and current flows through it, the first light-emitting diode (LED1) emits light; when the first return path is disconnected, the first light-emitting diode (LED1) does not emit light. Therefore, whether the first light-emitting diode (LED1) emits light can indicate the conductive / disconnected state of the first return path.

[0055] Similarly, the second return path, for example, also includes a second light-emitting diode (LED2), which is connected in series with the light source of the second photocoupler 142 and the light receiver of the first photocoupler 141. It should be understood that when the second return path is conductive and current flows through it, the second light-emitting diode (LED2) emits light; when the second return path is disconnected, the second light-emitting diode (LED2) does not emit light. Therefore, whether the second light-emitting diode (LED2) emits light can indicate the conductive / disconnected state of the second return path.

[0056] In some embodiments, the positive electrode of the light source (e.g., a light emitting diode) of the first photocoupler 141 is electrically connected to the proximal output terminal 121, the negative electrode of the light source of the first photocoupler 141 is electrically connected to one end of the light receiver of the second photocoupler 142, one end of the light receiver of the first photocoupler 141 is electrically connected to the remote output terminal 161, the other end of the light receiver of the first photocoupler 141 is electrically connected to the positive electrode of the light source of the second photocoupler 142, and the negative electrode of the light source of the second photocoupler 142 is electrically connected to the remote input terminal 162.

[0057] The isolation interlock unit 104 also includes, for example, a first reset switch KR1 and a second reset switch KR2. One end of the first reset switch KR1 is electrically connected to one end of the light receiver of the first photocoupler 141, and the other end of the first reset switch KR1 is electrically connected to the other end of the light receiver of the first photocoupler 141. That is, the first reset switch KR1 is connected in parallel with the light receiver of the first photocoupler 141. One end of the second reset switch KR2 is electrically connected to one end of the light receiver of the second photocoupler 142, and the other end of the second reset switch KR2 is electrically connected to the other end of the light receiver of the second photocoupler 142. The first reset switch KR1 and the second reset switch KR2 are configured to turn on in response to detecting that the reset signal is in an active state.

[0058] In some embodiments, the reset signal is generated by a reset button. For example, the first reset switch KR1 and the second reset switch KR2 are both controlled by the reset button. When the reset button is pressed, the first reset switch KR1 and the second reset switch KR2 are both turned on; when the reset button is released, the first reset switch KR1 and the second reset switch KR2 are both turned off.

[0059] In some embodiments, the reset signal is generated by the control device 123. For example, the first reset switch KR1 and the second reset switch KR2 are both controlled by the control device 123. When the control device 123 generates a reset signal in an active state (e.g., a high level state), the first reset switch KR1 and the second reset switch KR2 are both turned on; when the control device 123 generates a reset signal in an inactive state (e.g., a low level state), the first reset switch KR1 and the second reset switch KR2 are both turned off.

[0060] It is worth noting that the isolation interlock unit 104 enables the two optocouplers to be connected together by interconnecting each other, effectively isolating the signal (near-end current) on the control unit 102 side of the proximal device and the signal (far-end current) on the control unit 106 side of the remote device through the optical medium. At the same time, its high-speed response interlock mechanism can be used to ensure that after any side of the control unit 102 of the proximal device and the control unit 106 of the remote device responds to the emergency cut-off signal indicating a fault, the other side of the control unit 102 of the proximal device and the control unit 106 of the remote device are quickly synchronized, so that there is an extremely small response difference time between the control unit 102 of the proximal device and the control unit 106 of the remote device, thereby ensuring to a great extent the rapid and consistent simultaneous response of the signals on both sides of the control unit 102 of the proximal device and the control unit 106 of the remote device. Based on the design of the isolation interlock unit 104, the emergency shut-off control system 100 of the embodiment of the present disclosure can be provided with a reset button during normal use or self-detection function testing. When either the control unit 102 of the proximal device or the control unit 106 of the remote device responds to the emergency shut-off signal indicating a fault state, the current circuit can be reset by manually operating the reset button.

[0061] In some embodiments, the light source in the photocoupler is a light emitting diode, and the light receiver is a MOSFET (metal-oxide semiconductor field effect transistor). Figure 3As shown, the LEDs of the two optocouplers in the isolation interlock unit 104 are connected to the pins of the corresponding MOSFETs. When the system is operating normally, the LEDs of both optocouplers are operating normally, meaning the MOSFETs are in the on state. Accordingly, the LED indicators (LED1 and LED2) on both sides illuminate, indicating that both the local device 201 and the remote device 203 are operating normally, and the emergency shutdown signal issued indicates normal operation. When either the control unit 102 of the local device or the control unit 106 of the remote device enters an ESD emergency stop state (e.g., receives an emergency shutdown signal indicating a fault state), a short circuit occurs in the current loop. This causes the LED on the corresponding side of the optocoupler to enter a fault state (e.g., no current flows, no light is emitted), which in turn causes the MOSFET on the opposite side to disconnect. This in turn causes the LED of the optocoupler on the opposite side to enter a fault state (e.g., no current flows, no light is emitted), and the MOSFET on the local side is disconnected. Consequently, both MOSFETs are disconnected, triggering an ESD emergency stop response on both sides and achieving interlocking. After the problems on both sides are checked, the isolation interlock unit 104 can be reset to release the locked state.

[0062] The remote device control unit 106 is communicatively connected to the remote device 203 and electrically connected to the isolation interlock unit 104. The remote device control unit 106 includes at least a remote output terminal 161 and a remote input terminal 162. The remote output terminal 161 is configured to output a remote current to the isolation interlock unit 104, and the remote input terminal 162 is configured to receive the remote current flowing back through the second return path of the isolation interlock unit 104. The remote device control unit 106 is further configured to stop supplying the remote current to the isolation interlock unit in response to at least one of the following: detecting that the emergency shutdown signal from the remote device 203 indicates a fault state, and detecting that the flowing remote current is greater than a sixth predetermined current.

[0063] The control unit 106 of the remote device is also configured to: in response to detecting that the emergency shut-off signal represents a normal state and detecting that the remote current flowing back is less than or equal to the sixth predetermined current, output a remote current having a seventh predetermined current; and in response to detecting that the emergency shut-off signal represents a normal state and detecting that the remote current flowing back is greater than the first predetermined current, first stop outputting the remote current to the isolation interlock unit 104, and then output a remote current having an eighth predetermined current and connect at least the second return path, the seventh predetermined current being greater than the eighth predetermined current.

[0064] In some embodiments, the control unit 102 of the near-end device and the control unit 106 of the far-end device have the same or similar structure, which will not be described in detail here.

[0065] It is worth noting that after initialization, both the near-end device 201 and the far-end device 203 enter normal operation. The near-end device 201 transmits an emergency shutdown signal indicating a normal state to the near-end device's control unit 102. When the control device 123 detects that the emergency shutdown signal from the near-end device 201 indicates a normal state, the control device 123 outputs a first switch control signal corresponding to a normal state (e.g., a high-level signal) via its first output terminal O1. This causes the light source of the first switch unit K1 to emit light, thereby turning on the light receiver of the first switch unit K1. This connects one end of the first switch unit K1 to the other end.

[0066] Furthermore, at this time, the first branch is turned on, thereby outputting a proximal current having a fourth predetermined current. The first safety barrier 124 receives the proximal current having the fourth predetermined current from the first branch and outputs the proximal current having the fourth predetermined current at its output terminal. For example, the initial state of the selection signal output by the control device 123 corresponds to a state in which the first branch is turned on.

[0067] It is worth noting that after initialization is completed, the isolation interlock unit 104 is in a reset state. For example, the first reset switch KR1 and the second reset switch KR2 are both turned on. As a result, the proximal current output by the control unit 102 of the proximal device flows back to the proximal input terminal 122 of the control unit 102 of the proximal device via the isolation interlock unit 104. The light source of the first photocoupler 141 of the isolation interlock unit 104 emits light, causing the light receiver of the first photocoupler 141 to turn on. Similarly, the remote current output by the control unit 106 of the remote device flows back to the remote input terminal 162 of the control unit 106 of the remote device via the isolation interlock unit 104. The light source of the second photocoupler 142 of the isolation interlock unit 104 emits light, causing the light receiver of the second photocoupler 142 to turn on. As a result, the first reset switch KR1 and the second reset switch KR2 can be turned off.

[0068] Because the proximal current normally flows back to the control unit 102 of the proximal device via the isolation interlock unit 104 and the returned proximal current is within the normal range, the signals output by the first comparator U1 and the second comparator U2 both indicate that the returned proximal current is within the normal range. Accordingly, the states of the first switch unit K1 and the gate switch KS are maintained.

[0069] If the proximal current flowing back through the isolation interlock unit 104 is greater than the first predetermined current, the first comparator U1 outputs a high-level signal, turning on the first MOS transistor Q1 and pulling the control terminal of the first switch unit K1 to a low level. Consequently, the light source of the first switch unit K1 stops emitting light, and the light receiver of the first switch unit K1 is disconnected, i.e., the first switch unit K1 is disconnected. Consequently, both the first and second branches are disconnected, and the control unit 102 of the proximal device stops outputting proximal current to the isolation interlock unit 104. Consequently, the light source of the first photocoupler 141 of the isolation interlock unit 104 no longer has current flowing through it (the proximal current is less than the third predetermined current), and no longer emits light, causing the light receiver of the first photocoupler 141 of the isolation interlock unit 104 to be disconnected, i.e., the second return path is disconnected. In other words, the second return path is disconnected when the proximal current is less than the third predetermined current.

[0070] After the second return path is disconnected, the remote output terminal 161 and the remote input terminal 162 of the remote device's control unit 106 are disconnected, and the remote device's control unit 106 is unable to form a closed loop, and the remote device's control unit 106 is unable to continue to generate remote current. As a result, the light source of the second photocoupler 142 of the isolation interlock unit 104 has no current flowing through it (the remote current is less than the second predetermined current), and no longer emits light, causing the light receiver of the second photocoupler 142 of the isolation interlock unit 104 to be disconnected, that is, the first return path is disconnected. In other words, the first return path is disconnected when the remote current is less than the second predetermined current. Disconnecting either the first or second return path will also disconnect the other, hence the term "interlock."

[0071] Therefore, according to the emergency shutoff control system 100 of the embodiment of the present disclosure, when the proximal current flowing back is too large (greater than the first predetermined current), the current loop is disconnected, thereby effectively avoiding dangers (such as fire) caused by excessive current.

[0072] It is worth noting that the control device 123 receives a signal from the first comparator U1 via its first input terminal I1, indicating that the proximal return current is greater than a first predetermined current (i.e., the signal output by the first comparator U1). This allows the control device 123 to determine that the current loop is disconnected due to excessive current, not because the emergency shutdown signal indicates a fault condition. Therefore, based on the signal from the first comparator U1 indicating that the proximal return current is greater than the first predetermined current, the control device 123 generates a corresponding selection signal to control the two-choose-one switch KS, thereby connecting the second branch to the first switch unit K1 and disconnecting the first branch from the first switch unit K1. Furthermore, the control device 123 outputs a high-level first switch control signal to the first switch unit K1 via its first output terminal O1, thereby turning on the first switch unit K1. The control device 123 also generates a reset signal to reset the isolation interlock unit 104, thereby connecting the first and second return paths. Then, the control unit 102 of the near-end device re-forms a closed loop, and the control unit 106 of the far-end device re-forms a closed loop.

[0073] It can be seen that according to the emergency cut-off control system 100 of the embodiment of the present disclosure, when the proximal current flowing back is too large (greater than the first predetermined current), in addition to disconnecting the current loop, thereby effectively avoiding dangerous situations caused by excessive current, the generated proximal current can also be adaptively adjusted (for example, the proximal current is reduced), and the current loop can be reclosed to restore the transmission of emergency cut-off related signals between the proximal end and the distal end.

[0074] It should be understood that after the current loop of the control unit 102 of the proximal device is disconnected (the first switch unit K1 is disconnected and the first return path is disconnected), the signal output by the output end of the first comparator U1 returns to a low level, and the first MOS tube Q1 enters a cut-off (disconnected) state.

[0075] For example, in the emergency shutoff control system 100, the control unit 102 of the proximal device provides a proximal current in the range of 4 to 20 mA, and the power supply terminal VCC adopts a voltage of 24 V (volts). Appropriate resistors are configured, combined with the input terminal of the safety barrier, so that when the current loop is closed, a suitable proximal current, for example, a proximal current of 15 mA, is generated. It should be understood that when the current loop of the control unit 102 of the proximal device is disconnected, the proximal current is zero. When the emergency shutoff-related signal received by the control unit 102 of the proximal device from the proximal device 201 indicates a normal state, the current loop of the control unit 102 of the proximal device can be maintained in a closed state; when the emergency shutoff-related signal received by the control unit 102 of the proximal device from the proximal device 201 indicates a normal state, the current loop of the control unit 102 of the proximal device is disconnected.

[0076] The 15mA proximal current from the control unit 102 of the proximal device flows through the first return path of the isolation interlock unit 104. This current flows back to the proximal device control unit 102 while maintaining the second return path conductive, ensuring a closed current loop for the remote device control unit 106. The recirculated proximal current is sampled by the sampling resistor R6 and converted into a sampled voltage. The second comparator U2 then determines whether the emergency shutdown signal indicates a normal state or a fault state. For example, the second predetermined voltage corresponding to the signal VL is set to 10mA*R6. When the recirculated proximal current is greater than 10mA, the sampled voltage output by the sampling resistor R6 is greater than the second predetermined voltage, and the second comparator U2 outputs a high-level signal, indicating that the proximal device control unit 102 has not detected the emergency shutdown signal indicating a fault state. At this point, the control device 123 determines that the output of the second comparator is not in the first state (e.g., a low-level state), and the control device 123 does not output a shutdown control signal to the proximal device. Conversely, if the returned proximal current is less than 10 mA, the sampled voltage output by sampling resistor R6 is less than the second predetermined voltage, and second comparator U2 outputs a low-level signal, indicating that control unit 102 of the proximal device has detected an emergency shutdown-related signal indicating a fault state. At this point, control device 123 determines that the output of the second comparator is in the first state and outputs a shutdown control signal to the proximal device.

[0077] In addition, the sampled voltage output by the sampling resistor R6 is also transmitted to the first comparator U1 to determine whether the proximal current flowing back is greater than a first predetermined current. This prevents excessive proximal current from damaging the circuit unit or exceeding the explosion point due to excessive loop transmission current. When the proximal current flowing back is excessive (greater than the first predetermined current), the sampled voltage output by the sampling resistor R6 is greater than the first predetermined voltage, and the first comparator U1 outputs a high-level signal. The high-level signal output by the first comparator U1 not only drives the first MOS transistor Q1 to conduct, thereby turning off the first switch unit K1 of the control unit 102 of the proximal device, thus shutting off the transmission of the proximal current, but also notifies the control device 123 of the occurrence of a current limit over-limit event via the second input terminal I1 of the control device 123, so that the control device 123 can handle the event in accordance with the current limit over-limit mode. The related processing of the current over-limit mode includes, for example, first disconnecting the first branch and the second branch, then connecting the second branch, and resetting the isolation interlock unit 104 (connecting the first return path and the second return path).

[0078] If a fault occurs on the near-end device 201 side, the near-end device 201 transmits an emergency shutoff signal indicating a fault condition to the near-end device control unit 102. In response to detecting that the emergency shutoff signal from the near-end device 201 indicates a fault condition, the near-end device control unit 102 stops supplying near-end current to the isolation interlock unit 104. For example, in response to detecting that the emergency shutoff signal from the near-end device 201 indicates a fault condition, the control device 123 generates a first switch control signal for disconnecting the first switch unit K1. Consequently, both the first and second branches are disconnected, and the near-end device control unit 102 stops supplying near-end current to the isolation interlock unit 104. Consequently, the light source of the first photocoupler 141 of the isolation interlock unit 104 no longer flows with current (the near-end current is less than a third predetermined current) and no longer emits light, causing the light receiver of the first photocoupler 141 of the isolation interlock unit 104 to be disconnected, thereby disconnecting the second return path. Specifically, the second return path is disconnected when the near-end current is less than the third predetermined current.

[0079] After the second return path is disconnected, the remote output terminal 161 and the remote input terminal 162 of the remote device's control unit 106 are disconnected, preventing the remote device's control unit 106 from forming a closed loop and continuing to generate remote current. Consequently, the light source of the second photocoupler 142 of the isolation interlock unit 104 no longer flows with current (the remote current is less than the second predetermined current), and no longer emits light. This disconnects the light receiver of the second photocoupler 142 of the isolation interlock unit 104, effectively breaking the first return path. Specifically, the first return path is disconnected when the remote current is less than the second predetermined current.

[0080] Similarly, if a fault occurs on the remote device 203 side, the remote device 203 transmits an emergency shutoff signal indicating a fault condition to the remote device's control unit 106. In response to detecting that the emergency shutoff signal from the remote device 203 indicates a fault condition, the remote device's control unit 106 stops supplying remote current to the isolation interlock unit 104. For example, in response to detecting that the emergency shutoff signal from the remote device 203 indicates a fault condition, the control device 123 generates a first switch control signal for disconnecting the first switch unit K1. Consequently, both the first and second branches are disconnected, and the remote device's control unit 106 stops supplying near-end current to the isolation interlock unit 104. Consequently, the light source of the second photocoupler 142 of the isolation interlock unit 104 no longer emits light (the remote current is less than a second predetermined current), causing the light receiver of the second photocoupler 142 of the isolation interlock unit 104 to be disconnected, thereby disconnecting the first return path. Specifically, the first return path is disconnected when the remote current is less than the second predetermined current.

[0081] It should be understood that the second predetermined current and the third predetermined current are, for example, current values ​​that make the light source of the optocoupler (e.g., a light-emitting diode) insufficient to emit light. The third predetermined current is a reference value for the proximal current, and the second predetermined current is a reference value for the distal current. The predetermined lower limit current is a reference value for the recirculated proximal current. The predetermined lower limit current can be reasonably set according to needs. There is no necessary constraint between the predetermined lower limit current and the third predetermined current (or the second predetermined current). The predetermined lower limit current is not necessarily equal to the third predetermined current (or the second predetermined current). In some embodiments, the predetermined lower limit current is equal to the third predetermined current (or the second predetermined current). In some embodiments, the predetermined lower limit current is greater than the third predetermined current (or the second predetermined current). In some embodiments, the predetermined lower limit current is less than the third predetermined current (or the second predetermined current).

[0082] After the first return path is disconnected, the connection between the proximal output terminal 121 and the proximal input terminal 122 of the control unit 102 of the proximal device is disconnected, and the proximal device control unit 102 cannot form a closed loop, and the proximal device control unit 102 can no longer generate proximal current. Consequently, the light source of the first photocoupler 141 of the isolation interlock unit 104 no longer flows with current (the proximal current is less than the third predetermined current), and no longer emits light. This causes the light receiver of the first photocoupler 141 of the isolation interlock unit 104 to be disconnected, thus disconnecting the second return path. Specifically, the second return path is disconnected when the proximal current is less than the third predetermined current.

[0083] Regarding the working mechanism of the control unit 106 of the remote device, reference may be made to the control unit 102 of the local device, which will not be described in detail here.

[0084] The control unit 102 of the near-end device and the isolation interlock unit 104 , as well as the control unit 106 of the far-end device and the isolation interlock unit 104 , are electrically connected using cables that comply with SIGGTO (International Society of Gas Carriers and Terminal Operators) standards, for example.

[0085] The emergency shutoff control system 100, for example, further includes an internal loop switch unit 126 configured to conduct in response to detecting that a test signal is active, thereby providing a test path for the near-end current to flow back to the control unit 102 of the near-end device. The control unit 102 of the near-end device is further configured to disconnect from the isolation interlock unit 104 in test mode, assert the test signal, and generate the near-end current. The internal loop switch unit 126 is, for example, connected between the near-end output terminal 121 and the near-end input terminal 122. The internal loop switch unit 126 can be implemented using a photocoupler, with a control terminal of the internal loop switch unit 126 (e.g., the positive terminal of the light source of the photocoupler) electrically connected to the second output terminal O2 of the control device 123 via a fifth resistor R5. The control device 123 outputs a test signal via its second output terminal O2, which is used to control whether the internal loop switch unit 126 is open or closed.

[0086] For example, before connecting the control unit 102 of the local device to the isolation interlock unit 104, and before connecting the isolation interlock unit 104 to the control unit 106 of the remote device, a self-test can be performed internally within the local device's control unit 102 (or the remote device's control unit 106). Alternatively, a self-test can be performed internally within the local device's control unit 102 (or the remote device's control unit 106) after the aforementioned connections have been completed, for example, after the system has been operating for a period of time. In test mode, the local device's control unit 102 disconnects from the isolation interlock unit 104, asserts a test signal, and generates a local current. For example, the control device 123 outputs a test signal in a first state via its second output terminal O2, which is used to control the internal loop switch unit 126 to conduct. The control device 123 controls the first switch unit K1 to conduct, and controls the selector switch KS to enable the first branch. At this point, the local device's control unit 102 receives an emergency shutoff signal from the local device 201 indicating a normal state. The control device 123 then determines whether the control unit 102 of the near-end device is operating normally based on the signal output by the first comparator U1 and the signal output by the second comparator U2. For example, if the signal output by the first comparator U1 indicates that the recirculated near-end current is less than or equal to the first predetermined current, and the signal output by the second comparator U2 indicates that the recirculated near-end current is greater than or equal to the third predetermined current, then the internal self-test of the control unit 102 of the near-end device has succeeded and the control unit 102 of the near-end device is operating normally. Otherwise, it indicates that the control unit 102 of the near-end device is not operating normally.

[0087] When the emergency cut-off control system 100 has not been in operation for a long time, it will first perform a self-test and can be put into use after the self-test is normal. In the loop self-test mode, the emergency cut-off control system 100 can be tested by pressing the test button KT corresponding to the control unit 102 of the proximal device. The test button KT is, for example, a normally closed switch. When the test button KT is pressed, the switch is disconnected, and the path for the proximal device 201 to transmit the emergency cut-off signal to the control unit 102 of the proximal device is cut off. As a result, the control unit 102 of the proximal device detects that the emergency cut-off signal from the proximal device indicates a fault state. As a result, the emergency cut-off control system 100 enters the ESD emergency stop alarm mode. Among them, the isolation interlock unit 104 enters the interlock state, that is, the first return path and the second return path are both disconnected. Please refer to the previous text for the specific working principle, which will not be repeated here. Through the interlocking mechanism of the isolation interlock unit 104, the current loop of the control unit 106 of the remote device is disconnected, so that no remote current can be formed in the control unit 106 of the remote device. Accordingly, the remote device's control unit 106 generates a cutoff control signal and transmits it to the remote device 203. Thus, the simulated emergency cutoff signal indicating a fault condition during the test is actually transmitted to the remote device 203 via the emergency cutoff control system 100, thereby placing both the near-end and the remote-end in ESD emergency stop mode, indicating that the test is normal.

[0088] After the test is completed, a reset signal can be used to put the isolation interlock unit 104 into a reset state, that is, a state in which both the first return path and the second return path are conductive.

[0089] In addition, the emergency cut-off control system 100 is also provided with a disable button KF, for example. The function of the disable button KF is that when the emergency cut-off control system 100 is in normal operation, if personnel need to enter the danger zone, the disable button KF can be used to temporarily prevent the emergency cut-off control system 100 from responding to the emergency cut-off signal indicating a fault state. For example, if a person enters a danger zone, it will actually cause the proximal device 201 or the remote device 203 to send an emergency cut-off signal indicating a fault state. To ensure that the ESD system does not enter an alarm state while ensuring safe operation, the disable button KF can be pressed. The disable button KF is, for example, a normally open switch. When the disable button KF is pressed, it becomes closed (conducting), for example, to ensure that the proximal ESD is always in a closed loop state and the ESD system is manually disabled.

[0090] While various embodiments of the present disclosure have been described above, the foregoing description is intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technological improvements in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein.

[0091] The above are merely optional embodiments of the present disclosure and are not intended to limit the present disclosure. Those skilled in the art will readily appreciate that the present disclosure may be modified and varied in various ways. Any modifications, equivalent substitutions, improvements, and the like made within the spirit and principles of the present disclosure shall be included within the scope of protection of the present disclosure.

Claims

1. An emergency shutoff control system for target fluid transmission, wherein the target fluid is configured to be transmitted between a proximal device and a distal device, characterized in that: The emergency shutoff control system includes: a control unit of the proximal device, configured to output the proximal current to the isolation interlock unit and receive the proximal current flowing back through the isolation interlock unit, and configured to stop outputting the proximal current in response to detecting that the flowing proximal current is greater than a first predetermined current; an isolation interlock unit, comprising: a first return path for returning a proximal current to a control unit of a proximal device, and a second return path for returning a distal current to a control unit of a distal device, the isolation interlock unit being configured to disconnect the first return path when the distal current is less than a second predetermined current, and disconnect the second return path when the proximal current is less than a third predetermined current; and The control unit of the remote device is configured to output the remote current to the isolation interlock unit and receive the remote current flowing back through the isolation interlock unit.

2. The emergency shutoff control system according to claim 1, characterized in that: The control unit of the proximal device is further configured to: output a proximal current having a fourth predetermined current value in response to detecting that an emergency shut-off signal from the proximal device indicates a normal state and that the recirculated proximal current is less than or equal to a first predetermined current; and in response to detecting that the emergency shut-off signal indicates a normal state and that the recirculated proximal current is greater than the first predetermined current, first stop outputting the proximal current, and then connect the first return path and the second return path within a first predetermined time interval and output a proximal current having a fifth predetermined current value, wherein the fourth predetermined current value is greater than the fifth predetermined current value.

3. The emergency shutoff control system according to claim 2, characterized in that: The control unit of the proximal device is further configured to: output a cutoff control signal to the proximal device in response to detecting that the reflux proximal current is less than the predetermined lower limit current for a time greater than a second predetermined time, and the second predetermined time interval is greater than the first predetermined time interval.

4. The emergency shutoff control system according to claim 3, characterized in that: The control unit of the proximal device is further configured to stop outputting the proximal current in response to detecting that the emergency shutoff signal indicates a fault state.

5. The emergency shutoff control system according to claim 4, characterized in that: The control unit of the proximal device includes: The first branch is connected in parallel with the second branch and is configured to output a proximal current having a fourth predetermined current value; and a second branch configured to output a proximal current having a fifth predetermined current value; The control unit of the proximal device is further configured to: in response to detecting that the emergency shut-off signal indicates a fault state, disconnect the first branch and the second branch; in response to detecting that the emergency shut-off signal indicates a normal state and detecting that the recirculated proximal current is less than or equal to a first predetermined current, connect the first branch and disconnect the second branch; and in response to detecting that the emergency shut-off signal indicates a normal state and detecting that the recirculated proximal current is greater than the first predetermined current, first disconnect the first branch and the second branch, then connect the second branch, and connect the first return path and the second return path.

6. The emergency shutoff control system according to claim 5, characterized in that: The control unit of the proximal device also includes: a sampling resistor configured to receive the returned proximal current so as to output a sampling voltage; a first comparator, wherein a non-inverting input terminal of the first comparator is configured to receive the sample voltage, and an inverting input terminal of the first comparator is configured to receive a signal having a first predetermined voltage, the first predetermined voltage being related to the first predetermined current; and A first MOS transistor has a gate electrically connected to the output end of the first comparator, a source electrically connected to the ground, and a drain electrically connected to the control ends of the first branch and the second branch.

7. The emergency shutoff control system according to claim 6, characterized in that: The control unit of the proximal device also includes: a second comparator, one input terminal of the second comparator being configured to receive the sample voltage, and another input terminal of the second comparator being configured to receive a signal having a second predetermined voltage; and The control device is configured to output a disconnection control signal to the proximal device in response to detecting that the output terminal of the second comparator is in a first state for a period greater than a first predetermined time, and to output a control signal to the control terminals of the first branch and the second branch in response to detecting that an emergency disconnection signal from the proximal device indicates a fault state so that the first branch and the second branch are disconnected, wherein the first state corresponds to the proximal current flowing back being less than a predetermined lower limit current.

8. The emergency shutoff control system according to claim 1, characterized in that: Also includes: an inner loop switch unit configured to be turned on in response to detecting that the test signal is in an active state, so as to provide a test path for causing the near-end current to flow back to the control unit of the near-end device; The control unit of the proximal device is further configured to disconnect from the isolation interlock unit in the test mode, enable the test signal to be in an effective state, and generate a proximal current.

9. The emergency shutoff control system according to claim 1, characterized in that: The isolation interlock unit includes a first photocoupler and a second photocoupler, the first return path includes at least a light source of the first photocoupler and a light receiver of the second photocoupler, the light source of the first photocoupler and the light receiver of the second photocoupler are connected in series, and the second return path includes at least a light source of the second photocoupler and the light receiver of the first photocoupler, the light source of the second photocoupler and the light receiver of the first photocoupler are connected in series.

10. The emergency shutoff control system according to claim 9, characterized in that: The isolation interlock unit also includes: a first reset switch, one end of the first reset switch being electrically connected to one end of the light receiver of the first photoelectric coupler, and the other end of the first reset switch being electrically connected to the other end of the light receiver of the first photoelectric coupler; and a second reset switch, one end of the second reset switch being electrically connected to one end of the light receiver of the second photoelectric coupler, and the other end of the second reset switch being electrically connected to the other end of the light receiver of the second photoelectric coupler; The first reset switch and the second reset switch are configured to be turned on in response to detecting that the reset signal is in an active state.

11. The emergency shutoff control system according to claim 1, wherein: The proximal end is one of the source end and the destination end, and the remote end is the other of the source end and the destination end. The control unit of the remote device is further configured to stop outputting the remote current to the isolation interlock unit in response to at least one of the following: Detection of an emergency shutoff signal from a remote device indicating a fault condition; as well as It is detected that the remote current flowing back is greater than a sixth predetermined current.

12. The emergency shutoff control system according to claim 5, characterized in that: The control unit of the proximal device also includes: a first safety barrier, wherein an input end of the first safety barrier is electrically connected to output ends of the first branch and the second branch, and an output end of the first safety barrier is configured to output a proximal current; and The second safety barrier has an input end configured to receive the refluxed proximal current, and an output end of the second safety barrier is electrically connected to the sampling resistor.

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