Method and device for automatically changing ends of locomotive

Abstract

The invention relates to the technical field of rail transit, and discloses an automatic locomotive end changing method and device. The automatic locomotive end changing method comprises the following steps: acquiring signals related to locomotive end changing on a locomotive and actual states corresponding to two pantographs respectively; judging whether the locomotive meets end changing conditions or not according to the logic relation between the signals; if it is confirmed that the locomotive meets the condition, a pantograph rising holding signal is sent to the pantograph in the pantograph rising state, and a pantograph rising signal is sent to the other pantograph so that end changing can be conducted. According to the scheme, automatic locomotive end changing can be achieved, the environmental influence degree in the manual locomotive end changing process is reduced, and the technical effect that the pantograph does not descend in the end changing process is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of rail transportation, and in particular relates to a method and a device for automatic end change of a locomotive. Background Art

[0002] With the development of rail transit technology, electric locomotives play an increasingly important role in rail traction transportation. The current electric locomotives include DC electric locomotives, electric locomotives introduced through technology after 2004, and new electric locomotives independently developed in China.

[0003] There are still more than 10,000 DC electric locomotives and electric locomotives introduced through technology after 2004. These electric locomotives do not have the automatic end-changing function like new electric locomotives. In the existing technology, the locomotive operator manually changes the end. The main circuit breaker is disconnected, the pantograph is lowered, and the electric key is disconnected in the driver's cab at one end of the locomotive. Then, the electric key is closed, the pantograph is raised, and the main circuit breaker is closed in the driver's cab at the other end of the locomotive to complete the end change. This locomotive end-changing method is greatly affected by weather and environment. For example, in severe environments such as heavy haze, dense fog, and cold winter, when the locomotive operator changes the locomotive end, it is very easy to cause arc discharge, top net, pantograph cannot be raised normally, etc., causing the locomotive to be unable to operate normally, thereby affecting railway transportation scheduling and traction transportation tasks.

[0004] Therefore, there is an urgent need for an automatic terminal switching method suitable for DC electric locomotives. Summary of the invention

[0005] In view of the problem that the manual locomotive end-changing method in the prior art is greatly affected by the weather and environment, and is very likely to cause arc discharge, top grid, pantograph failure to rise normally and other faults in harsh environments, resulting in the locomotive being unable to operate normally, the main purpose of the present invention is to provide a method and device for automatic locomotive end-changing.

[0006] In order to solve at least one of the above technical problems, the present invention adopts the following technical solution: According to one aspect of the present invention, a method for automatically changing ends of a locomotive is provided, comprising: Collect the signals on the locomotive related to the locomotive end change, as well as the actual status of the two pantographs; Determining whether the locomotive meets the end-changing condition according to the logical relationship between the signals; If it is confirmed that the locomotive meets the conditions, a pantograph raising and holding signal is sent to the pantograph in the pantograph raising state, and a pantograph raising signal is sent to the other pantograph to switch ends.

[0007] In some embodiments, the method further comprises: In response to the completion of the end change, a pantograph raising stop signal is sent to the pantograph that sends the pantograph raising holding signal.

[0008] In some embodiments, the step of collecting signals on the locomotive related to the locomotive end change includes: Collect the electric key status signal, end change signal, controller status signal of the driver's cab at both ends of the locomotive, and the command signal sent to the two pantographs respectively; The isolation signals of the two pantographs, the locomotive speed signal, and the locomotive main circuit breaker status signal are collected.

[0009] In some embodiments, the step of judging whether the locomotive meets the end-changing condition according to the logical relationship between the signals comprises: Determining whether there is a confirmation signal in the end-change signal of the driver's cabs at both ends of the locomotive; If there is a confirmation signal in the end-change signal of the driver's cab at both ends of the locomotive, determine whether there is an insertion state in the electric key state signal of the driver's cab at both ends of the locomotive; If the electric key state signal of the driver's cab at one end is in the inserted state, it is determined whether the pantograph raising command signal sent by the driver's cab at the end matches the actual state of the pantograph; In response to the match, it is determined whether the controller status signal is a zero-position status signal, whether the isolation signals of the two pantographs are non-isolated status signals, whether the locomotive speed signal is a zero-speed signal, and whether the locomotive main circuit breaker status signal is a closed status signal, and whether the locomotive meets the end-changing conditions is confirmed based on the judgment results.

[0010] In some embodiments, the step of confirming whether the locomotive meets the end change condition according to the judgment result includes: If the controller status signal is a zero-position status signal, the isolation signals of the two pantographs are non-isolated status signals, the locomotive speed signal is a zero-speed signal, and the locomotive main circuit breaker status signal is a closed status signal, it is confirmed that the locomotive meets the end-changing conditions.

[0011] In some embodiments, the method for automatically changing the end of a locomotive further includes: In response to the matching being inconsistent, the locomotive end-changing mode is exited.

[0012] In some embodiments, the method further comprises: If it is confirmed that the locomotive meets the conditions, an on signal is sent to the indicator lights in the driver's cab at both ends of the locomotive to instruct the driver to change ends.

[0013] According to another aspect of the present invention, there is also provided a locomotive automatic terminal change device for a DC electric locomotive, comprising a control host, wherein the control host is used to: Collect the signals on the locomotive related to the locomotive end change, as well as the actual status of the two pantographs; Determining whether the locomotive meets the end-changing condition according to the logical relationship between the signals; If it is confirmed that the locomotive meets the conditions, a pantograph raising and holding signal is sent to the pantograph in the pantograph raising state, and a pantograph raising signal is sent to the other pantograph to switch ends.

[0014] In some embodiments, the device for automatically changing the end of a locomotive further comprises: A terminal change indicator light, which is used to turn on when receiving a start signal to instruct the driver to change terminals.

[0015] In some embodiments, the device for automatically changing the end of a locomotive further comprises: A power module, the power module is used to provide power to the control host and the end-change indicator light; A relay is used to isolate and convert the signal collected by the control host for collection by the control host.

[0016] By adopting the above technical scheme, according to the method for automatic end change of the locomotive of the present invention, the signals related to the end change of the locomotive and the actual states corresponding to the two pantographs are collected on the locomotive, and the locomotive is judged whether it meets the end change condition according to the logical relationship between the signals. If it is confirmed that the locomotive meets the end change condition, a pantograph raising and holding signal is sent to the pantograph in the pantograph raising state, and a pantograph raising signal is sent to the other pantograph to change the end. According to the method for automatic end change of the locomotive of the present invention, there is no need for the locomotive operator to perform the end change operation at both ends of the locomotive successively, and the locomotive can be automatically changed. The degree of environmental influence during the manual end change of the locomotive is reduced, and the occurrence of faults such as arc discharge, top net, and pantograph failure to be raised normally is reduced to ensure the normal operation of the locomotive. At the same time, according to the logical relationship between the collected signals, it is judged whether the locomotive meets the end change condition. Only when the locomotive meets the end change condition, a holding signal is sent to the pantograph currently in the pantograph raising state, and a pantograph raising signal is sent to the other pantograph at the same time. Both pantographs are in the pantograph raising state, and the technical effect of not lowering the pantograph during the end change process is achieved.

[0017] At the same time, a locomotive automatic end-changing device of the present invention can also achieve the above-mentioned technical effects, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A flow chart of a method for automatically changing ends of a locomotive provided by a first embodiment of the present invention; Figure 2 An electrical principle block diagram of a method for automatically changing ends of a locomotive provided in accordance with a second embodiment of the present invention; Figure 3 It is a schematic diagram of the structure of the device for automatically changing the end of a locomotive provided in the third embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0021] It should be understood that the embodiments of the present invention shown in the exemplary embodiments are only illustrative. Although only a few embodiments are described in detail in the present invention, it is easy for those skilled in the art to appreciate that multiple modifications are feasible without actually departing from the teaching of the subject matter of the present invention. Accordingly, all such modifications should be included within the scope of the present invention. Without departing from the gist of the present invention, other replacements, modifications, changes and deletions may be made to the design, operating conditions and parameters of the following exemplary embodiments.

[0022] It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for distinguishing two non-identical entities with the same name or non-identical parameters. It can be seen that "first" and "second" are only for the convenience of expression and should not be understood as limitations on the embodiments of the present invention. The subsequent embodiments will not explain this one by one.

[0023] According to one aspect of the present invention, a method for automatically changing ends of a locomotive is disclosed, such as Figure 1 As shown, Figure 1 The flowchart of a method for automatically changing ends of a locomotive provided by the first embodiment of the present invention is shown. The method 100 for automatically changing ends of a locomotive comprises: Step 101, collecting signals on the locomotive related to the locomotive end change, and the actual states of the two pantographs respectively; Step 102: judging whether the locomotive meets the end-changing condition according to the logical relationship between the signals; Step 103: If it is confirmed that the locomotive meets the conditions, a pantograph raising and holding signal is sent to the pantograph in the pantograph raising state, and a pantograph raising signal is sent to the other pantograph to switch ends.

[0024] The above-mentioned locomotive end-changing method does not require the locomotive operator to perform end-changing operations at both ends of the locomotive in succession, and can realize automatic end-changing of the locomotive, thereby reducing the degree of environmental influence during the manual end-changing of the locomotive, and reducing the occurrence of faults such as arc discharge, top net, and pantograph failure to rise normally, so as to ensure the normal operation of the locomotive. At the same time, according to the logical relationship between the collected signals, it is judged whether the locomotive meets the end-changing conditions. Only when the locomotive meets the end-changing conditions, a holding signal is sent to the pantograph currently in the pantograph raising state, and a pantograph raising signal is sent to the other pantograph at the same time. Both pantographs are in the pantograph raising state, achieving the technical effect of not lowering the pantograph during the end-changing process.

[0025] According to several embodiments of the present invention, a method for automatically changing ends of a locomotive further includes: in response to completing the end change, sending a pantograph raising stop signal to the pantograph that sent the pantograph raising hold signal.

[0026] According to some embodiments of the present invention, the step of collecting signals related to the locomotive end change on the locomotive includes: collecting the electric key status signal, end change signal, controller status signal of the driver's cab at both ends of the locomotive, and the command signal sent to the two pantographs respectively; collecting the isolation signal of the two pantographs, the locomotive speed signal, and the locomotive main circuit breaker status signal. Collecting multiple signals related to the locomotive end change, through logical judgment between them, it can be finally determined whether the locomotive is changing ends, so as to realize the automatic end change of the locomotive.

[0027] According to some embodiments of the present invention, the step of judging whether the locomotive meets the end-changing condition according to the logical relationship between the signals includes: judging whether there is a confirmation signal in the end-changing signal of the driver's cab at both ends of the locomotive; if there is a confirmation signal in the end-changing signal of the driver's cab at both ends of the locomotive, judging whether there is an insertion state in the electric key status signal of the driver's cab at both ends of the locomotive; if the electric key status signal of the driver's cab at one end is the insertion state, judging whether the pantograph raising command signal sent by the driver's cab at the end matches the actual state of the pantograph; in response to the matching, judging whether the controller state signal is a zero-position state signal, whether the isolation signals of the two pantographs are non-isolated state signals, whether the locomotive speed signal is a zero-speed signal, and whether the locomotive main circuit breaker state signal is a closed state signal, and judging whether the locomotive meets the end-changing condition according to the judgment result. Only when the driver wants to change ends, further judging whether the pantograph raising command signal sent by the driver's cab currently at the main control end to the pantograph matches the actual state of the pantograph, and when matching, further judging is performed to confirm whether the locomotive meets the end-changing condition, so as to change ends without lowering the pantograph.

[0028] According to some embodiments of the present invention, the step of confirming whether the locomotive meets the end-changing condition according to the judgment result includes: if the controller state signal is a zero-position state signal, the isolation signals of the two pantographs are non-isolated state signals, the locomotive speed signal is a zero-speed signal, and the locomotive main circuit breaker state signal is a closed state signal, confirming that the locomotive meets the end-changing condition. The end-changing can only be performed if the end-changing condition is met, further ensuring the accuracy of the locomotive's automatic end-changing and minimizing the locomotive operation abnormality caused by judgment errors.

[0029] According to some embodiments of the present invention, the method for automatic locomotive end change also includes: in response to inconsistent matching, exiting the locomotive end change mode. If the pantograph raising instruction sent by the driver's cab to the pantograph is inconsistent with the corresponding actual state, it means that there is an abnormality in the state of the pantograph, or there is an abnormality in the communication between the driver's cab and the pantograph, which is conducive to further improving the abnormality handling capability of the locomotive automatic end change.

[0030] According to some embodiments of the present invention, a method for automatically changing ends of a locomotive further includes: if it is confirmed that the locomotive meets the conditions, sending an on signal to the indicator lights in the driver's cab at both ends of the locomotive to instruct the driver to change ends.

[0031] According to another aspect of the present invention, there is also provided a device for automatic end change of a locomotive, which is used for a DC electric locomotive. The device for automatic end change of a locomotive includes a control host, which is used to: collect signals on the locomotive related to the locomotive end change, and the actual states corresponding to the two pantographs; determine whether the locomotive meets the end change conditions according to the logical relationship between the signals; if it is confirmed that the locomotive meets the conditions, send a pantograph holding signal to the pantograph in the pantograph raising state, and send a pantograph raising signal to the other pantograph to change the ends.

[0032] According to some embodiments of the present invention, the device for automatically changing ends of a locomotive further includes: an end change indicator light, the indicator light being configured to turn on when receiving an on signal to instruct the driver to change ends.

[0033] According to some embodiments of the present invention, the locomotive automatic end change device also includes: a power module, which is used to provide power to the control host and the end change indicator light; and a relay, which is used to isolate and convert the signals collected by the control host for collection by the control host.

[0034] In order to further understand the locomotive end-changing method of the present invention, it is further described in detail in a specific embodiment. In this embodiment, the automatic end-changing of a DC electric locomotive is used as an example for explanation. It can be understood that the method of the present invention is not limited to DC electric locomotives, and can be applied to locomotives without automatic end-changing function.

[0035] Please refer to Figure 2 , Figure 2Shown is an electrical principle block diagram of a method for automatic end change of a locomotive provided by the second embodiment of the present invention. A DC electric locomotive has two pantographs. During normal operation, generally only one of the pantographs will be raised to contact the contact network to obtain electrical energy. Signal line 358 and signal line 400 are power lines that can provide a 110V power signal. A DC electric locomotive has two driver's cabs at both ends, and it is necessary to collect signals from the two driver's cabs separately. Specifically, the signals related to the locomotive end change and the actual states corresponding to the two pantographs are collected on the locomotive, the electric key status signals, end change signals, controller status signals of the driver's cabs at both ends of the locomotive, and the command signals sent to the two pantographs are collected, and the isolation signals of the two pantographs, the locomotive speed signal, and the locomotive main circuit breaker status signal are also collected.

[0036] The signal lines Z1 and Z2 are collected to collect the end-changing signals of the cabs at both ends of the locomotive. When the signal is 1, it indicates that the end-changing signal is in the confirmation state, so as to determine whether the driver wants the locomotive to change ends. When the signal line Z1 and the signal line Z2 have a signal of 1, the signal lines 501 and 601 are further collected to collect the electric key status signals of the cabs at both ends of the locomotive. The signal is 1, indicating that the electric key status signal is an insertion status signal, which means that the corresponding cab is the main control. When the signal line 501 and the signal line 601 have a signal of 1, the signal lines 514, 515, 614 and 615 are further collected. The signal is 1, indicating that the signal sent by the cab to the corresponding pantograph is a pantograph raising signal, so as to determine to which pantograph the cab is currently sending the pantograph raising signal. At the same time, the actual status of the two pantographs is collected, and the actual status of the pantograph is compared with the command issued by the driver's cab to determine whether the two match. If they match, it means that the actual status of the pantograph corresponding to the pantograph raising signal sent by the driver's cab to the pantograph is the pantograph raising state, indicating that there is no abnormality, and then further determine whether the controller status signal is a zero-position state signal, whether the isolation signals of the two pantographs are non-isolated state signals, whether the locomotive speed signal is a zero-speed signal, and whether the locomotive main circuit breaker state signal is a closed state signal. Otherwise, exit the locomotive end-changing mode. Collect signal lines 421 and 422 to collect the isolation signals of the two pantographs to determine whether the pantographs are currently in an isolated state. When the signal is 1, it means that it is in an isolated state, and the locomotive is not allowed to change ends. Only when the two pantographs are in a non-isolated state can the locomotive be operated to change ends. Collect signal lines 503 and 603 to collect the controller status signals of the two driver's cabs. The signal is 1, which means it is in a zero-position state signal. If any one of the signals is 1, it is one of the conditions for confirming that the locomotive meets the end-changing condition. The acquisition signal line 831 is used to acquire the locomotive speed signal. The signal is 1, indicating that the locomotive is in the zero speed state signal, which is one of the conditions for confirming that the locomotive meets the end change. The acquisition signal line 431 is used to acquire the locomotive main circuit breaker state signal. The signal is 1, indicating that the locomotive is in the closed state signal, which is one of the conditions for confirming that the locomotive meets the end change.

[0037] Please continue to refer to Figure 2 If it is confirmed that the locomotive meets the end-changing conditions, a pantograph raising and holding signal is sent to the pantograph in the pantograph raising state, such as sending a pantograph raising and holding signal to signal line 451 or signal line 452, and sending a pantograph raising signal to the remaining other pantograph, and the output signal drives the electromagnetic valve of the pantograph, and the corresponding pantograph is raised to change ends. At the same time, an opening signal is sent to the indicator lights LP1 and LP2 in the driver's cab at both ends of the locomotive, driving the indicator lights to light up, to instruct the driver to change ends.

[0038] The above-mentioned method of automatic end-changing of locomotives does not require locomotive operators to perform end-changing operations at both ends of the locomotive in succession, and can realize automatic end-changing of locomotives, thereby reducing the degree of environmental influence during manual end-changing of locomotives, and reducing the occurrence of faults such as arc discharge, top net, and pantograph failure to rise normally, so as to ensure the normal operation of the locomotive. At the same time, according to the logical relationship between the collected signals, it is judged whether the locomotive meets the end-changing conditions. Only when the locomotive meets the end-changing conditions, a holding signal is sent to the pantograph currently in the pantograph raising state, and a pantograph raising signal is sent to the other pantograph at the same time. Both pantographs are in the pantograph raising state, achieving the technical effect of not lowering the pantograph during the end-changing process.

[0039] According to another aspect of the present invention, there is also provided a locomotive automatic terminal switching device for a DC electric locomotive, see Figure 3 The device for automatic locomotive end-changing includes a control host, which is used to: collect signals related to locomotive end-changing on the locomotive, and the actual states of the two pantographs; determine whether the locomotive meets the conditions for end-changing according to the logical relationship between the signals; if it is confirmed that the locomotive meets the conditions, send a pantograph-raising and holding signal to the pantograph in the pantograph-raising state, and send a pantograph-raising signal to the other pantograph to change ends. The control host can collect locomotive signals and instructions for changing ends without lowering the pantograph, and control the end-changing process according to the locomotive state to maintain the pantograph raised state.

[0040] According to some embodiments of the present invention, the device for automatically changing ends of a locomotive further includes: an end change indicator light, the indicator light being configured to turn on when receiving an on signal to instruct the driver to change ends.

[0041] According to some embodiments of the present invention, the locomotive automatic end-changing device further includes: a power module, which is used to provide power to the control host and the end-changing indicator light; and a relay, which is used to isolate and convert the signal collected by the control host for collection by the control host. The power supply device can convert the locomotive control power supply into a 24V power supply system to supply the control host.

[0042] In addition, the locomotive automatic end-changing device also includes an automatic switch, which is a protection device for the internal power supply of the device. When a fault occurs inside the device, the automatic switch is disconnected, which can cut off the connection with the locomotive. The locomotive automatic end-changing device also includes a normal indicator light, which lights up when the control host is powered and passes the self-test, indicating that the control host is working normally.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of implementation of the present invention. If the present invention is modified or replaced by equivalents without departing from the spirit and scope of the present invention, it should be included in the protection scope of the claims of the present invention.

[0044] A person skilled in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the protection scope of the embodiments of the present invention.

Claims

1. A method for automatically changing the end of a locomotive, characterized in that: include: Collect the signals on the locomotive related to the locomotive end change, as well as the actual status of the two pantographs; Determining whether the locomotive meets the end-changing condition according to the logical relationship between the signals; If it is confirmed that the locomotive meets the conditions, a pantograph raising and holding signal is sent to the pantograph in the pantograph raising state, and a pantograph raising signal is sent to the other pantograph to switch ends.

2. The method for automatic locomotive end change according to claim 1, characterized in that: The method further comprises: In response to the completion of the end change, a pantograph raising stop signal is sent to the pantograph that sends the pantograph raising holding signal.

3. The method for automatic locomotive end change according to claim 1, characterized in that: The step of collecting signals on the locomotive related to the locomotive end change includes: Collect the electric key status signal, end change signal, controller status signal of the driver's cab at both ends of the locomotive, and the command signal sent to the two pantographs respectively; The isolation signals of the two pantographs, the locomotive speed signal, and the locomotive main circuit breaker status signal are collected.

4. The method for automatic locomotive end change according to claim 3, characterized in that: The step of judging whether the locomotive meets the end-changing condition according to the logical relationship between the signals comprises: Determining whether there is a confirmation signal in the end-change signal of the driver's cabs at both ends of the locomotive; If there is a confirmation signal in the end-change signal of the driver's cab at both ends of the locomotive, determine whether there is an insertion state in the electric key state signal of the driver's cab at both ends of the locomotive; If the electric key state signal of the driver's cab at one end is in the inserted state, it is determined whether the pantograph raising command signal sent by the driver's cab at the end matches the actual state of the pantograph; In response to the match, it is determined whether the controller status signal is a zero-position status signal, whether the isolation signals of the two pantographs are non-isolated status signals, whether the locomotive speed signal is a zero-speed signal, and whether the locomotive main circuit breaker status signal is a closed status signal, and whether the locomotive meets the end-changing conditions is confirmed based on the judgment results.

5. The method for automatically changing the end of a locomotive according to claim 4, characterized in that: The step of confirming whether the locomotive meets the end change condition according to the judgment result includes: If the controller status signal is a zero-position status signal, the isolation signals of the two pantographs are non-isolated status signals, the locomotive speed signal is a zero-speed signal, and the locomotive main circuit breaker status signal is a closed status signal, it is confirmed that the locomotive meets the end-changing conditions.

6. The method for automatically changing the end of a locomotive according to claim 4, characterized in that: The method further comprises: In response to the matching being inconsistent, the locomotive end-changing mode is exited.

7. The method for automatic locomotive end change according to claim 1, characterized in that: The method further comprises: If it is confirmed that the locomotive meets the conditions, an on signal is sent to the indicator lights in the driver's cab at both ends of the locomotive to instruct the driver to change ends.

8. A device for automatically changing the end of a locomotive, characterized in that: Used in DC electric locomotive, comprising a control host, the control host is used for: Collect the signals on the locomotive related to the locomotive end change, as well as the actual status of the two pantographs; Determining whether the locomotive meets the end-changing condition according to the logical relationship between the signals; If it is confirmed that the locomotive meets the conditions, a pantograph raising and holding signal is sent to the pantograph in the pantograph raising state, and a pantograph raising signal is sent to the other pantograph to switch ends.

9. The device for automatically changing the end of a locomotive according to claim 8, characterized in that: Also includes: A terminal change indicator light, which is used to turn on when receiving a start signal to instruct the driver to change terminals.

10. The device for automatically changing the end of a locomotive according to claim 9, characterized in that: Also includes: A power module, the power module is used to provide power to the control host and the end-change indicator light; A relay is used to isolate and convert the signal collected by the control host for collection by the control host.

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