Automatic barrel change detection device of drawing frame

Abstract

The utility model discloses an automatic barrel change detection device of a drawing frame, which belongs to the technical field of barrel change detection of the drawing frame and comprises a barrel in-place detection sensor arranged on one side of a barrel change station and used for detecting whether a barrel is in place or not and outputting a shielding signal; the manual barrel changing confirmation module is arranged on the operation panel and is used for triggering a barrel changing completion signal in a shutdown state; the control circuit is electrically connected with the barrel in-place detection sensor and the manual barrel changing confirmation module, and the control circuit comprises an interlocking logic unit and a driving unit; and the starting device is connected with the driving unit of the control circuit and is used for driving the drawing frame to operate. According to the utility model, through non-contact detection of the barrel in-place detection sensor, a full barrel state can be identified in real time and a shutdown instruction can be triggered, and in combination with triple interlocking logic of the manual barrel changing confirmation module and the barrel changing time window, a false start path when the barrel is not changed is reliably blocked from a circuit level, so that the safety of the barrel is ensured. And the problem of cotton sliver accumulation caused by no empty barrel for bearing is avoided.

Description

Technical Field

[0001] This utility model relates to the field of can-changing detection technology for drawing frames, and specifically to an automatic can-changing detection device for drawing frames. Background Technology

[0002] In the textile industry, the drawing frame is a key piece of equipment that combines and drafts cotton slivers or other fiber slivers to improve evenness. In the drawing frame production process, can changing is an indispensable step: when the cotton sliver collection can is full, it needs to be manually replaced with an empty can to maintain continuous production.

[0003] Traditional drawing frames rely heavily on manual judgment and operation for can changing. If a worker fails to change a full can in time or forgets to perform the can-changing action, and accidentally presses the start button, the machine will continue running even without an empty can, causing slivers to accumulate at the exit or in the collection bin. This not only wastes materials and damages sliver quality but can also lead to equipment component damage due to mechanical overload, and even affect the production quality of subsequent processes.

[0004] Existing control circuits typically lack real-time detection devices for the drum status or rely solely on traditional detection methods such as mechanical contacts. For example, some equipment detects the presence of a drum using mechanical contact switches, but these switches are prone to failure due to lint buildup and mechanical wear, resulting in unreliable detection signals. Furthermore, mechanical contacts cannot provide real-time feedback on whether drum replacement is complete, making it difficult to directly prevent accidental starts at the circuit level. Accidental starts leading to material accumulation require machine shutdown and cleanup, increasing worker workload and production line downtime. Additionally, accumulated material may cause equipment malfunctions, posing safety hazards.

[0005] Based on this, this utility model designs an automatic drum changing detection device for a drawing frame to solve the above problems. Utility Model Content

[0006] In view of the above-mentioned shortcomings of the existing technology, the present invention provides an automatic can-changing detection device for a drawing frame.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] An automatic can-changing detection device for a drawing frame includes:

[0009] The bucket in position detection sensor (I16) is set on one side of the bucket changing station to detect whether the bucket is in position and output an obstruction signal;

[0010] The manual drum replacement confirmation module (I22) is located on the operation panel and is used to trigger a drum replacement completion signal when the machine is stopped.

[0011] The control circuit is electrically connected to the bucket in-place detection sensor (I16) and the manual bucket replacement confirmation module (I22). The control circuit includes an interlocking logic unit and a drive unit.

[0012] The starting device (M4) is connected to the drive unit of the control circuit and is used to drive the drawing frame to run;

[0013] The interlocking logic unit is configured to: determine a full bucket state when the bucket presence detection sensor continuously detects a bucket presence signal, trigger a stop command, and cut off the power supply circuit of the start-up device; only when the bucket presence detection sensor detects a bucket removal signal, the manual bucket replacement confirmation module is triggered, and a preset bucket replacement time window has elapsed, the drive unit of the control circuit restores the power supply circuit via a self-locking relay and allows start-up; wherein, within the bucket replacement time window, if the fluctuation rate of the bucket presence signal is >10% for three consecutive cycles (100ms per cycle), the start-up process is interrupted and an alarm is triggered.

[0014] The interlocking logic unit includes an AND gate circuit (IC1), whose input terminals are respectively connected to the signal line of the bucket in-situ detection sensor and the signal line of the manual bucket replacement confirmation module.

[0015] Furthermore, the bucket-changing time window is set by the timer module of the PLC controller, with a time range of 5-30 seconds, and the timing is started only when the bucket removal signal and the manual bucket-changing confirmation signal are both valid.

[0016] Furthermore, the barrel in-situ detection sensor (I16) is a reflective laser sensor, installed on the inside of the drawing machine head on the side of the barrel changing station, with the detection direction perpendicular to the barrel movement path and the detection distance being 10-30cm.

[0017] Furthermore, the interlocking logic unit is implemented through a PLC controller, which has the following preset program: when the bucket in position signal changes from high level to low level and the manual bucket replacement confirmation signal (I22) remains high for ≥1 second, the bucket replacement time window countdown is started; if the fluctuation rate of the bucket in position signal is >10% for 3 consecutive sampling cycles (100ms per cycle) during the countdown period (the historical average is the average value of the stable signal 30 seconds before the bucket replacement) or the bucket in position signal recovers, the timer is reset and the start device is locked.

[0018] Furthermore, the output of the interlocking logic unit is connected to the control terminal of the self-locking relay via an optocoupler isolator.

[0019] Furthermore, the control circuit includes a self-locking relay (M4), which maintains a self-locking state after the power supply circuit is turned on until the bucket presence detection sensor (I16) detects the bucket presence signal again.

[0020] Furthermore, it also includes a module for verifying the integrity of the bucket-changing action, which is configured as follows:

[0021] During the drum replacement time window, the voltage fluctuation of the drum in place signal is monitored in real time by ADC sampling. If the signal voltage fluctuation exceeds ±0.5V or the fluctuation frequency exceeds 10Hz (i.e., ΔV / Δt>0.1V / ms), the drum replacement action is determined to be abnormal and an alarm is triggered.

[0022] Furthermore, the signal from the manual bucket replacement confirmation module (I22) and the bucket removal signal from the bucket presence detection sensor (I16) are connected to an AND gate logic through the PLC internal logic unit or hardware AND gate circuit, and the timing result of the bucket replacement time window is connected to the start-up circuit through an OR gate logic.

[0023] The signal from the manual bucket replacement confirmation module (I22) and the bucket removal signal from the bucket in-place detection sensor (I16) form an AND gate logic, and the timing result of the bucket replacement time window is connected to the start-up circuit through an OR gate logic.

[0024] Furthermore, the control circuit also includes an anti-interference circuit, the circuit comprising:

[0025] Optical isolators are used to isolate electrical noise in sensor signals;

[0026] Digital filter to filter out pulse interference shorter than 0.5 seconds.

[0027] Furthermore, it also includes an alarm device. When the barrel changing action is not completed within the barrel changing time window or an abnormal signal is detected, the control circuit drives the alarm device to issue an audible and visual warning and lock the start device.

[0028] Furthermore, the drive unit of the control circuit includes a bistable relay. The first contact of the relay is connected in series with the power supply circuit of the starting device (M4), and the second contact is connected to the alarm device. When the interlocking logic unit determines that the drum replacement is not completed, the first contact opens and the second contact closes to trigger the alarm.

[0029] Furthermore, the time window for changing the sliver is dynamically adjusted according to the linear density of the sliver: it is set to 15-30 seconds when the linear density is ≥5g / m; and 5-15 seconds when the linear density is <5g / m. The weight of the sliver is detected in real time by a weighing sensor (model HBMZ6FC3) installed at the sliver outlet, and the PLC automatically matches the preset value of the T102 timer according to the weight-linear density conversion formula.

[0030] Compared with the prior art, the advantages of this utility model are as follows:

[0031] 1. This utility model uses a non-contact detection sensor to identify the full status of the drum in real time and trigger a stop command. Combined with the triple interlocking logic of the manual drum replacement confirmation module and the drum replacement time window, it reliably blocks the path of accidental start when the drum has not been replaced from the circuit level, avoiding the problem of cotton swab accumulation caused by no empty drum to receive the swab. It uses a reflective laser sensor to replace the traditional mechanical contacts, avoiding detection failure caused by cotton lint accumulation and mechanical wear, realizing stable monitoring of the drum status, and significantly improving the automation level and detection reliability of the drum replacement operation.

[0032] 2. The barrel-changing time window of this utility model is precisely set by a PLC timer, and the timer only starts when the barrel removal signal and the manual confirmation signal are both valid, ensuring that the barrel-changing action is completed within the specified time, standardizing the operation process and reducing human error. The anti-interference module (optical isolator, digital filter) in the control circuit can effectively filter out electrical noise and transient interference in the sensor signal; the barrel-changing action integrity verification module monitors the signal stability in real time, triggers an alarm and locks the starting device when abnormal, further improving the safety of system operation; the application of self-locking relays and bistable relays realizes the automatic maintenance of the power supply circuit and rapid disconnection in abnormal conditions; the logic gate operation design of the manual barrel-changing confirmation signal and the barrel status signal makes the control logic more compact and reduces the probability of malfunction. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a system structure block diagram of an automatic can-changing detection device for a drawing frame according to the present invention;

[0035] Figure 2 This is a flowchart illustrating the interlocking logic of an automatic can-changing detection device for a drawing frame according to this utility model.

[0036] Figure 3 This is a timing signal variation diagram of an automatic can-changing detection device for a drawing frame according to the present invention;

[0037] Figure 4 This is a schematic diagram showing the installation position of the bucket in-place detection sensor in an automatic bucket changing detection device for a drawing frame according to this utility model.

[0038] Figure 5 This is a schematic diagram of the time-frequency domain joint verification of the anti-interference optical coupler sensor system of this utility model;

[0039] Figure 6 This is a comparison spectrum diagram of the present invention before and after filtering. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0041] This embodiment provides an automatic drum-changing detection device for a drawing frame. Through multi-level interlocking logic, it achieves precise control of the drum-changing action, effectively preventing material accumulation or equipment damage caused by misoperation. Figure 1-4 As shown, the device mainly includes the following core components:

[0042] The drum presence detection sensor (I16), a reflective laser sensor, model Banner QS18VP6LPQ, is mounted on an aluminum alloy bracket inside the head of the winch, 15cm horizontally from the side of the drum. The detection direction is perpendicular to the drum's movement path, and the effective detection distance is adjustable from 10 to 30cm.

[0043] The manual drum replacement confirmation module (I22) and the waterproof and dustproof button (model EAO 84-series) are located on the lower right side of the operation panel. The contacts are made of silver alloy, with a rated current of 5A, and are connected to the X0 input terminal of the PLC.

[0044] The control circuit, based on a Siemens S7-1200 PLC, expands with digital input modules (6ES7 221-1BH32-0XB0) and output modules (6ES7 222-1HF32-0XB0), and incorporates interlocking logic. Its hardware mapping is as follows:

[0045] The bucket in-place detection sensor (I16) is connected to the DI0.0 port; the manual bucket replacement confirmation module (I22) is connected to the DI0.1 port; the start device drive signal (M4) is output from the DO1.0 port; and the alarm device signal is output from the DO1.1 port.

[0046] The drive unit includes a self-locking relay (Omron MY4N-GS, coil voltage 24VDC) and a bistable relay (Finder 40.52.8.024.0000).

[0047] The anti-interference circuit uses a TLP521-4 optocoupler isolator and an RC low-pass filter (R=10kΩ, C=100nF, cutoff frequency 160Hz).

[0048] This anti-interference circuit uses an optocoupler isolator as its core and is combined with an RC filter network.

[0049] The optocoupler (U1) is model TLP521-4, which provides electrical isolation between its input and output sides. The connection method is as follows:

[0050] On the input side (LED end), a 10kΩ current-limiting resistor is connected in series from the sensor signal end (I16) and then connected to the input pin of the optocoupler U1 to form an input signal path;

[0051] On the output side (transistor end), a 100nF decoupling capacitor is connected in parallel to the output pin of optocoupler U1 and grounded (GND). At the same time, this output pin is connected to the input terminal I0.0 of the PLC.

[0052] In the RC filter network section, a 10kΩ resistor is connected in series in the LED circuit on the input side of the optocoupler to suppress surge current; a 100nF capacitor is connected in parallel between the output side of the optocoupler and ground to filter out high-frequency interference signals below 200MHz, such as electromagnetic interference generated by the frequency converter.

[0053] The anti-interference logic works as follows: the sensor signal first passes through a 10kΩ resistor for current limiting, then drives the optocoupler LED. The optocoupler internally uses photoelectric conversion to transmit the signal to the transistor side. A 100nF capacitor further filters out voltage fluctuations, finally inputting a clean signal to the PLC's I0.0 terminal, thus achieving anti-interference transmission and electrical isolation.

[0054] The overall circuit connection is as follows:

[0055] Regarding the control signal flow, the signal output by the anti-interference circuit (i.e. the signal received by the I0.0 terminal of the PLC) enters the PLC for logic operation. The result of the operation is output from the Q0.1 and Q0.2 terminals of the PLC to control the SET and RESET coils of the self-locking relay, thereby driving the action of the K1-1 contact.

[0056] Regarding power supply and grounding, the optocoupler input side and the sensor share a 24V DC power supply; the optocoupler output side, the PLC control circuit, and the self-locking relay coil share the same ground terminal (GND) to ensure that the reference potential of each part remains consistent.

[0057] The mounting structure of the barrel in-situ detection sensor (I16) includes:

[0058] The beam is calibrated to a distance of 25cm between the sensor transmitter and receiver, and the laser positioning device (accuracy ±0.1mm) is used to ensure that the beam is perpendicular to the movement path of the barrel.

[0059] Signal conditioning: The sensor output signal is optically isolated and then connected to an RC filter to eliminate instantaneous interference caused by floating cotton fibers (filter time constant τ=10ms).

[0060] The PLC program uses ladder diagram programming, and the key logic flow is as follows:

[0061] During the bucket-changing trigger phase, the PLC scans the I16 signal and calculates the fluctuation rate every 100ms. A CTD decrement counter (preset value 3) is used. When |(current value - historical average) / historical average|×100%>10% for 3 consecutive cycles (100ms / cycle), the counter decrements by 1. When it decrements to 0, an alarm is triggered. If a high level is detected or the counter returns to 0, T102 is reset and Q0.1 output is locked, and the alarm device is triggered simultaneously.

[0062] During the startup permission phase, after the countdown of T102 ends, if I16 is still low, the PLC sets M4.1, drives the self-locking relay to close, and at the same time, the SET coil of the bistable relay is energized, thus connecting the startup circuit.

[0063] The input / output sides of the optocoupler are equipped with independent power supplies (isolation voltage 5000Vrms). The digital filter uses a capacitor connected in parallel with a TVS diode (SMAJ5.0A) to suppress surge voltage. The PLC program is set to verify the validity of the signal. The signal is considered valid only if five consecutive samples are consistent. If the fluctuation rate of the I16 signal exceeds 10% within the drum changing time window (calculation formula: ΔV / Δt>0.1V / ms), it is judged as abnormal and triggers the E02 alarm.

[0064] It is worth mentioning that the PLC program uses ladder logic programming and is written based on TIAPortalV17 software. The key logic is implemented through the following instructions:

[0065] For full barrel detection, the T3 timer (preset value T#3s) is configured using the TON (on delay) instruction. When DI0.0 (I16) remains high for more than 3 seconds, the normally open contact of T3 closes, and M10.0 is activated by the S (set) instruction.

[0066] The bucket replacement time window is determined by identifying the falling edge (bucket removal) of DI0.0 using the R_TRIG (rising edge detection) instruction. This edge is then connected in series with the S instruction self-holding logic of DI0.1 (I22) to trigger the T102 timer (TON instruction, adjustable from preset value T#5s to T#30s).

[0067] The DI0.0 signal is sampled using a CTU (increment counter) with a sampling period of 100ms. The signal is considered valid when five consecutive samples are consistent, thus avoiding misjudgment caused by cotton lint interference.

[0068] A laser positioning instrument (model LaserAlign Pro-X) was used to calibrate the distance between the sensor transmitter and receiver, with the error controlled within ±0.1mm, ensuring that the vertical angle deviation between the beam and the barrel's moving path was ≤0.5°.

[0069] Install a magnetic ring filter (TDK ZCAT2035-0930) on the sensor signal line to suppress interference in the frequency band below 200MHz caused by the frequency converter.

[0070] In addition, the alarm device in this solution includes a 95dB buzzer (KD1206) and a red LED warning light (24V / 3W), which are installed on the top of the control panel;

[0071] To release the interlock, press and hold the I22 button for 5 seconds and enter the administrator password (default 123456). The PLC will output a reset signal through the DO1.2 port to clear the alarm flag and unlock the start circuit.

[0072] For low-cost application scenarios, the following variant solutions can be adopted:

[0073] The reflective laser sensor was replaced with a microwave sensor (Sick UM30-213111), increasing the detection distance to 50cm; an Arduino + relay module was used to replace the PLC, and basic interlocking functions were implemented through hard-wired logic.

[0074] The working principle of this solution is as follows:

[0075] When the amount of cotton swabs in the tub reaches the preset capacity, the reflective laser sensor (I16) continuously detects a tub presence signal (high level), and the PLC controller responds with the following logic:

[0076] Immediately disconnect the power supply circuit of the starting device (M4) to stop the sling machine from running, trigger the audible and visual alarm device to prompt the operator to change the drum, lock the start button on the control panel to prevent accidental activation, and after hearing the alarm, the operator must go to the drum changing station, press the emergency stop button on the control panel (independent of I22), and after confirming that the equipment has completely stopped, begin removing the full drum.

[0077] The operator moves the full bucket out of the workstation along the slide rail. At this time, the I16 sensor detects the bucket removal signal (low level). The empty bucket is pushed into the workstation. The operator presses the bucket replacement completion button (I22, interval ≤ 0.5 seconds) twice in succession and simultaneously presses and holds the reset button for more than 1 second. After the PLC detects the I16 low level (bucket removal) and I22 high level (manual confirmation) signals, it starts the bucket replacement time window countdown (adjustable from 5 to 30 seconds). During this period, if the following abnormalities are detected, the countdown will be stopped immediately and an alarm will be triggered: the operator releases the I22 button prematurely; the empty bucket is not fully in place (I16 signal fluctuation rate > 10%); external interference is detected (such as cotton lint blocking the sensor for more than 0.5 seconds).

[0078] If no abnormal signal is detected within the drum changing time window, the PLC executes the following actions: the self-locking relay (M4) is closed to restore the power supply circuit; the SET coil of the bistable relay is energized to activate the starting device; and the operation panel is unlocked, allowing the draw frame to restart.

[0079] The self-locking relay (K1) adopts a dual-coil independent power supply structure. The SET coil is connected to the Q0.1 terminal of the PLC and connected in series with a 1N4007 diode. The RESET coil is connected to the Q0.2 terminal (independent 24V power supply, hardware interlock circuit prevents the two coils from conducting at the same time). The contacts are connected in series in the main circuit of the starting device. The optocoupler (U1) is a TLP521-4. A 10kΩ current-limiting resistor is connected in series between the input side and the sensor, and a 100nF decoupling capacitor is connected in parallel on the output side.

[0080] When an abnormal situation occurs, such as a timeout during bucket changing or no empty bucket arrival signal is detected after the countdown ends, the PLC triggers the E01 alarm code, locks the start device, and requires an administrator password to reset. In case of accidental reset, if a high level is detected on I16 during bucket changing (e.g., a full bucket is accidentally pushed back), the PLC immediately resets the countdown; triggers the E02 alarm code; and forcibly cuts off the power to the drive unit, requiring a manual restart of the control circuit.

[0081] The self-locking relay (K1) employs a dual-coil independent control structure, and its connection method is as follows:

[0082] One end of the SET coil is connected to the output terminal Q0.1 of the PLC (Programmable Logic Controller), and the other end is connected to the common terminal of the control circuit;

[0083] One end of the RESET coil is connected to the output terminal Q0.2 of the PLC, and the other end shares a common terminal with the SET coil;

[0084] The main contact (K1-1) is a normally open contact, connected in series in the main circuit of the starting device. The main circuit starts from the positive terminal of the 24V DC power supply, passes through the K1-1 contact, connects to the motor (M), and finally returns to the negative terminal of the power supply, forming the main current circuit.

[0085] The logical control relationship is as follows:

[0086] When the PLC outputs a high-level signal Q0.1, the SET coil is energized, causing the K1-1 contact to close, and the main circuit is then turned on.

[0087] When the PLC outputs a high-level signal Q0.2, the RESET coil is energized, forcing the K1-1 contact to open, and the main circuit is cut off.

[0088] The coil adopts a dual-coil self-locking design. After the SET coil is triggered, no continuous power supply is required and the contacts can remain closed. Only the RESET signal can release the self-locking.

[0089] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. An automatic can-changing detection device for a drawing frame, characterized in that, include: A bucket in-place detection sensor is installed on one side of the bucket changing station to detect whether the bucket is in place and output an obstruction signal. The manual drum replacement confirmation module is located on the operation panel and is used to trigger a drum replacement completion signal when the machine is stopped. The control circuit is electrically connected to the bucket in-place detection sensor and the manual bucket replacement confirmation module. The control circuit includes an interlocking logic unit and a drive unit. A starting device, connected to the drive unit of the control circuit, is used to drive the drawing frame to run; The interlocking logic unit is configured as follows: When the bucket presence detection sensor continuously detects a bucket presence signal, it determines that the bucket is full, triggers a stop command, and cuts off the power supply circuit of the start-up device; Only when the bucket presence detection sensor detects a bucket removal signal, the manual bucket replacement confirmation module is triggered, and after a preset bucket replacement time window has elapsed, the drive unit of the control circuit restores the power supply circuit through a self-locking relay and allows startup. The self-locking relay maintains a self-locking state after the power supply circuit is turned on until the bucket presence detection sensor detects the bucket presence signal again.

2. The automatic can-changing detection device for a drawing frame according to claim 1, characterized in that, The bucket-changing time window is set by the timer module of the PLC controller, with a time range of 5-30 seconds, and the timer is started only when the bucket removal signal and the manual bucket-changing confirmation signal are both valid.

3. The automatic can-changing detection device for a drawing frame according to claim 1, characterized in that, The barrel in-situ detection sensor is a reflective laser sensor, installed on the inside of the drawing machine head on the side of the barrel changing station. The detection direction is perpendicular to the barrel movement path, and the detection distance is 10-30cm.

4. The automatic can-changing detection device for a drawing frame according to claim 1, characterized in that, The interlocking logic unit is implemented through a PLC controller, which has the following preset programs: When the bucket in place signal changes from high level to low level, and the manual bucket replacement confirmation signal (I22) remains high for ≥1 second, the bucket replacement time window countdown starts. If no bucket presence signal is detected before the countdown ends, startup is allowed; If the bucket is in place signal is restored during the countdown, the timer is reset and the starting device is locked.

5. The automatic can-changing detection device for a drawing frame according to claim 1, characterized in that, The control circuit includes a self-locking relay, which maintains a self-locking state after the power supply circuit is turned on, until the bucket in position detection sensor detects the bucket in position signal again.

6. The automatic can-changing detection device for a drawing frame according to claim 4, characterized in that, It also includes a bucket-changing action integrity verification module, which is configured as follows: During the bucket replacement time window, the stability of the bucket position signal is monitored in real time. If the signal fluctuation exceeds the preset threshold, the bucket replacement action is determined to be abnormal and an alarm is triggered.

7. The automatic can-changing detection device for a drawing frame according to claim 1, characterized in that, The signal from the manual bucket replacement confirmation module and the bucket removal signal from the bucket presence detection sensor are connected to an AND gate logic through the PLC internal logic unit or hardware AND gate circuit, and the timing result of the bucket replacement time window is connected to the start-up circuit through an OR gate logic.

8. The automatic can-changing detection device for a drawing frame according to claim 1, characterized in that, The control circuit further includes an anti-interference circuit, which includes: Optical isolators are used to isolate electrical noise in sensor signals; Digital filter to filter out pulse interference shorter than 0.5 seconds.

9. The automatic can-changing detection device for a drawing frame according to claim 1, characterized in that, It also includes an alarm device. When the barrel changing action is not completed within the barrel changing time window or an abnormal signal is detected, the control circuit drives the alarm device to issue an audible and visual prompt and lock the start device.

10. The automatic can-changing detection device for a drawing frame according to claim 1, characterized in that, The drive unit of the control circuit includes a bistable relay. The first contact of the relay is connected in series with the power supply circuit of the starting device, and the second contact is connected to the alarm device. When the interlocking logic unit determines that the drum replacement is not completed, the first contact opens and the second contact closes to trigger the alarm.

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