Tension control device

Abstract

This tension control device (2) is provided with: a load signal acquisition unit (251) that acquires, from a tension detector (1), a load signal indicating the tension of a long material; a determination unit (252) that, when zero adjustment processing is completed, shifts to a span adjustment mode for performing span adjustment processing, and determines that the load signal is at a constant load on the basis of a voltage value corresponding to the magnitude of the load signal acquired by the load signal acquisition unit (251) after the zero adjustment processing; and a setting unit (253) that sets, as a span adjustment value, a voltage value corresponding to the magnitude of the load signal at a constant load determined by the determination unit (252).

Description

Tension Control Device

[0001] The present disclosure relates to a tension control device for controlling the tension of a long material.

[0002] In converting machines, tension detectors are used as tension sensors to control the tension of web materials such as paper, film, wire rod, etc. In converting machines, a driving device that applies tension to the web material and a tension control device that controls the driving device to control the tension of the web material are used in combination.

[0003] When using a tension control device, the start-up procedure requires a zero adjustment process, which cancels the tare load, and the zero-adjusted adjustment value must be stored. Also, when using a tension control device, the start-up procedure requires a span adjustment process, which predetermines the maximum tension of the web material, and the span-adjusted adjustment value must be stored. Each converting machine has different conditions, such as the mounting position of the tension detector, the mounting angle of the tension detector, and the angle at which the web material is positioned. For this reason, it is essential to perform the zero adjustment process and the span adjustment process as part of the tension control device start-up procedure before operating the converting machine.

[0004] Patent Document 1 describes a tension control device that, when using two tension detectors to measure the tension of an object made of a long material such as a film, performs span adjustment on the two tension detectors, converts the output signals input from the tension detectors into analog-to-digital signals using an AD converter of 16 bits or more, and stores the converted digital signals as span adjustment values.

[0005] Japanese Patent Application Laid-Open No. 2004-333298

[0006] In converting machines, the installation location of a tension control device with an operating unit for performing span adjustment is often far from the installation location of a detection roller unit from which a weight for span adjustment is hung. When using the tension control device described in Patent Document 1, an operator must perform zero adjustment using the operating unit of the tension control device, then go to the installation location of the detection roller unit, hang a weight on the detection roller, and return to the installation location of the tension control device to perform span adjustment. In other words, the operator must travel between the installation location of the tension control device and the installation location of the detection roller unit, which places a burden on the operator.

[0007] The present disclosure has been made in view of the above, and aims to provide a tension control device that reduces the burden on an operator and makes setup work easy.

[0008] In order to solve the above-mentioned problems and achieve the object, the tension control device according to the present disclosure is a tension control device that performs zero adjustment processing and span adjustment processing of a tension detector and controls the tension of a long material transported by a feed mechanism based on adjustment values ​​obtained by the zero adjustment processing and span adjustment processing. The tension control device includes: a load signal acquisition unit that acquires a load signal indicating the tension of the long material from the tension detector; a determination unit that, when the zero adjustment processing is completed, transitions to a span adjustment mode that performs span adjustment processing and determines that the load signal is a load signal at a constant load based on a voltage value corresponding to the magnitude of the load signal acquired by the load signal acquisition unit after the zero adjustment processing; and a setting unit that sets the voltage value corresponding to the magnitude of the load signal at the constant load determined by the determination unit as a span adjustment value.

[0009] According to the present disclosure, it is possible to obtain a tension control device that reduces the burden on an operator and makes setup work easy.

[0010] FIG. 1 is a diagram showing the configuration of a tension control system according to a first embodiment. FIG. 2 is a diagram showing an example of the configuration of a feed mechanism provided in the tension control system according to the first embodiment. FIG. 3 is a diagram showing an example of the state when zero adjustment is performed in the feed mechanism provided in the tension control system according to the first embodiment. FIG. 4 is a diagram showing an example of the state when span adjustment is performed in the feed mechanism provided in the tension control system according to the first embodiment. FIG. 5 is a diagram showing an example of the configuration of a tension detector provided in the tension control system according to the first embodiment. FIG. 6 is a diagram showing an example of the configuration of a tension control device provided in the tension control system according to the first embodiment. A flowchart showing an example of the procedures for zero adjustment processing and span adjustment processing of a tension control system in embodiment 3. A conceptual diagram showing the relationship between the span adjustment time during span adjustment of a tension control system in embodiment 3 and the voltage value corresponding to the magnitude of the load signal. A flowchart showing an example of the procedures for zero adjustment processing and span adjustment processing of a tension control system in embodiment 4. A conceptual diagram showing the relationship between the span adjustment time during span adjustment of a tension control system in embodiment 4. A diagram showing a configuration in which each function of a control unit according to embodiments 1 to 4 is realized by hardware. A diagram showing a configuration in which each function of a control unit according to embodiments 1 to 4 is realized by software.

[0011] A tension control device according to an embodiment will be described in detail below with reference to the drawings.

[0012] 1 is a diagram showing the configuration of a tension control system according to embodiment 1. The tension control system 100 according to embodiment 1 has a function of applying tension to a web material in a converting machine.

[0013] The web material is a freely deformable long material, and may be a strip-shaped sheet material such as paper or film, or a linear material such as a string. In the first embodiment, the web material will be described as a string.

[0014] The tension control system 100 according to the first embodiment includes a tension detector 1, a tension control device 2, and a feed mechanism 3. The tension detector 1 and the tension control device 2 are communicatively connected via a network 4. The tension control device 2 and the feed mechanism 3 are communicatively connected via the network 4. The network 4 includes, for example, a wide area network (WAN) such as the Internet and a mobile communication network. The tension control device 2 and the tension detector 1, or the tension control device 2 and the feed mechanism 3, may be communicatively connected via dedicated wiring.

[0015] The feed mechanism 3 transports the web material and applies an appropriate tension to the web material when converting the web material. Fig. 2 is a diagram showing an example of the configuration of a feed mechanism included in the tension control system according to the first embodiment. Fig. 3 is a diagram showing an example of a state when zero adjustment is performed in the feed mechanism included in the tension control system according to the first embodiment. Fig. 4 is a diagram showing an example of a state when span adjustment is performed in the feed mechanism included in the tension control system according to the first embodiment. The feed mechanism 3 includes a feed unit 31, a mechanism communication unit 32, and a mechanism control unit 33.

[0016] The feed section 31 conveys the web material and applies tension to the web material when converting the web material, and includes a first roller 311, a second roller 312, a third roller 313, a fourth roller 314, a left bearing 315L, a right bearing 315R, an unwinding roller 316, and a winding roller 317.

[0017] The left bearing 315L is connected to one end, or left end, of the second roller 312 in the longitudinal direction. The right bearing 315R is connected to the other end, or right end, of the second roller 312 in the longitudinal direction.

[0018] It should be noted that the illustration does not include bearings provided on rollers other than the second roller 312. The feed unit 31 also includes other devices that are generally used in converting machines, such as a powder brake, a feed motor, a main shaft motor, and a take-up motor (not shown), but their description will be omitted.

[0019] The web material unwound from the unwinding roller 316 is hooked onto the first roller 311, the second roller 312, the third roller 313 and the fourth roller 314, and is sent in this order, and is finally wound up by the winding roller 317.

[0020] The second roller 312 functions as a detection roller for detecting a load signal indicative of tension in the web material.

[0021] The web material wound on the detection roller is called spool material, and the unwind roller 316 and the take-up roller 317 on which the web material is wound are called spools.

[0022] The mechanism communication unit 32 is connected to the network 4 and communicates with the tension control device 2 via the network 4. The mechanism communication unit 32 receives control information for controlling the feed mechanism 3, which is transmitted from the tension control device 2, and transmits the control information to the mechanism control unit 33.

[0023] The mechanism control unit 33 controls the entire feed mechanism 3. The mechanism control unit 33 controls the feed unit 31 based on control information transmitted from the tension control device 2. That is, the mechanism control unit 33 controls the driving units, such as the brake and motor, of the feed unit 31 based on the control information transmitted from the tension control device 2, thereby conveying the web material and applying tension to the web material.

[0024] The tension detector 1 detects the load acting on the second roller 312, which functions as a detection roller for detecting a load signal indicative of the tension of the web material, and generates a load signal as data indicative of the tension of the web material. The tension detector 1 transmits the load signal to the tension control device 2. In other words, the tension detector 1 functions as a tension meter that measures the tension of the web material in a taut state.

[0025] The tension control system 100 has a left tension detector 1L and a right tension detector 1R as tension detectors 1. The left tension detector 1L is connected to a left end, which is one end in the longitudinal direction of the second roller 312, which functions as a detection roller. The right tension detector 1R is connected to a right end, which is the other end in the longitudinal direction of the second roller 312, which functions as a detection roller.

[0026] 5 is a diagram showing an example of the configuration of the tension detectors provided in the tension control system according to embodiment 1. The left tension detector 1L and the right tension detector 1R, which are the tension detectors 1, have the following common configuration.

[0027] The tension detector 1 includes a strain gauge sensor 11, a detector storage unit 12, a detector communication unit 13, and a detector control unit 14. The components of the tension detector 1 can exchange information with each other.

[0028] The strain gauge type sensor 11 detects the load acting on the second roller 312, which functions as a detection roller for detecting a load signal indicative of the tension of the web material, and generates a load signal as data indicative of the tension of the web material. The strain gauge type sensor 11 transmits the load signal to the detector control unit 14. The strain gauge type sensor 11 of the left tension detector 1L transmits the generated load signal to the detector control unit 14 as a left load signal. The strain gauge type sensor 11 of the right tension detector 1R transmits the generated load signal to the detector control unit 14 as a right load signal. In other words, the strain gauge type sensor 11 functions as a detection unit that detects data indicative of the tension of the web material.

[0029] The detector storage unit 12 stores various information used to control the tension detector 1 .

[0030] The detector communication unit 13 is connected to the network 4 and communicates with the tension control device 2 via the network 4. The detector communication unit 13 receives the load signal generated by the strain gauge type sensor 11 from the detector control unit 14 and transmits the received load signal to the tension control device 2. In other words, the detector communication unit 13 functions as a load signal output unit that outputs the load signal detected by the strain gauge type sensor 11 to the tension control device 2.

[0031] The detector control unit 14 controls the entire tension detector 1 .

[0032] The tension control device 2 controls the tension of the web material being transported by the feed mechanism 3. When controlling the tension of the web material, the tension control device 2 also estimates and corrects the tension of the web material using the load signal obtained from the tension detector 1. The tension control device 2 functions as a controller for automatically controlling the tension of the web material, which is the degree of tension of the web material during transport, to a constant level in various web material processing processes.

[0033] Fig. 6 is a diagram showing an example of the configuration of a tension control device provided in the tension control system according to the first embodiment. Fig. 6 shows a state in which the zero adjustment value is stored in the storage unit 23 after the zero adjustment has been performed. Fig. 7 is a diagram showing an example of the configuration of a tension control device provided in the tension control system according to the first embodiment. Fig. 7 shows a state in which the zero adjustment value and the span adjustment value are stored in the storage unit 23 after the span adjustment has been performed.

[0034] The tension control device 2 includes an operation unit 21 , a display unit 22 , a storage unit 23 , a communication unit 24 , a processing unit 25 , and a control unit 26 .

[0035] The operation unit 21 is an input unit that accepts setting operations from an operator. The operation unit 21 accepts setting operations input by the operator and transmits information corresponding to the setting operations to the processing unit 25 or the control unit 26.

[0036] The display unit 22 displays information within the tension control device 2. The display unit 22 is a display device such as an LCD (Liquid Crystal Display) or an organic EL (Electro Luminescence) display.

[0037] The storage unit 23 stores various types of information used to control the tension control device 2, such as information acquired from outside the tension control device 2 and information created inside the tension control device 2. The storage unit 23 stores a zero adjustment value and a span adjustment value.

[0038] The communication unit 24 is connected to the network 4 and communicates with devices external to the tension control device 2 via the network 4 .

[0039] The processing unit 25 performs processing related to tension control of the web material transported by the feed mechanism 3. The processing unit 25 performs zero adjustment processing and span adjustment processing. The processing unit 25 includes a load signal acquisition unit 251, a determination unit 252, a setting unit 253, and a tension control unit 254.

[0040] The load signal acquisition unit 251 acquires a load signal from the tension detector 1. The load signal acquisition unit 251 receives and acquires the left load signal transmitted from the left tension detector 1L and the right load signal transmitted from the right tension detector 1R via the communication unit 24. The load signal acquisition unit 251 converts the acquired load signal into a voltage value corresponding to the magnitude of the load signal and transmits it to the memory unit 23, the determination unit 252, the setting unit 253, or the tension control unit 254. Hereinafter, the voltage value corresponding to the magnitude of the load signal may be simply referred to as a voltage value.

[0041] The determination unit 252 determines whether or not a voltage value corresponding to the magnitude of the load signal acquired by the load signal acquisition unit 251 is equal to or greater than a predetermined threshold. If the voltage value corresponding to the magnitude of the load signal acquired by the load signal acquisition unit 251 is equal to or greater than a predetermined threshold, the determination unit 252 determines that the load signal is a load signal at a constant load. If the determination unit 252 determines that the load signal is a load signal at a constant load, the determination unit 252 transmits the voltage value corresponding to the magnitude of the load signal at the constant load to the storage unit 23 to store it as a span adjustment value. The determination unit 252 stores a connection threshold Vth1 and a span adjustment threshold Vth2 as thresholds for making determinations in the span adjustment process.

[0042] The constant load state corresponds to a state in which a constant load is applied to the web material stretched over the detection roller of the feed mechanism 3, and corresponds to a state in which the weight 111 is suspended from the detection roller of the feed mechanism 3.

[0043] The connection threshold Vth1 is a judgment reference value that the judgment unit 252 uses to determine whether the tension detector 1 is connected to the tension control device 2 by comparing it with a voltage value corresponding to the magnitude of the load signal obtained from the tension detector 1.

[0044] The span adjustment threshold value Vth2 is a judgment reference value used by the judgment unit 252 to determine whether the load signal obtained from the tension detector 1 is a load signal at a constant load by comparing it with a voltage value corresponding to the magnitude of the load signal, and is a judgment reference value used to determine whether the weight 111 is hung on the second roller 312 that functions as a detection roller in the feed unit 31 of the feed mechanism 3.

[0045] The setting unit 253 sets the zero adjustment value and the span adjustment value stored in the storage unit 23 in the tension control unit 254 .

[0046] The tension control unit 254 controls the feed mechanism 3 based on a voltage value corresponding to the magnitude of the load signal acquired from the tension detector 1, thereby adjusting the tension of the web material. When the tension control device 2 is in the operating mode, the tension control unit 254 acquires a voltage value corresponding to the magnitude of the load signal acquired from the tension detector 1 from the load signal acquisition unit 251, and corrects the acquired voltage value using the zero adjustment value and span adjustment value set by the setting unit 253. The tension control unit 254 controls the feed mechanism 3 based on the corrected voltage value and predetermined adjustment conditions.

[0047] The control unit 26 controls the entire tension control device 2 .

[0048] Next, an overview of the span adjustment process in the tension control device 2 will be described. First, it is determined whether both the left tension detector 1L and the right tension detector 1R are connected to the tension control device 2, or whether either the left tension detector 1L or the right tension detector 1R is connected to the tension control device 2. Next, based on the determination result of the connection status of the left tension detector 1L and the right tension detector 1R to the tension control device 2, a voltage value corresponding to the magnitude of the load signal acquired from the tension detector 1 connected to the tension control device 2 is stored as a span adjustment value.

[0049] Before the weight 111 is suspended from the detection roller, neither the left-side voltage value Vl, which is a voltage value corresponding to the magnitude of the left-side load signal acquired from the left-side tension detector 1L, nor the right-side voltage value Vr, which is a voltage value corresponding to the magnitude of the right-side load signal acquired from the right-side tension detector 1R, becomes equal to or greater than the span adjustment threshold value Vth2. Therefore, the processing unit 25 waits until either the left-side voltage value Vl or the right-side voltage value Vr becomes equal to or greater than the span adjustment threshold value Vth2, or until the non-connection determination time Tb has elapsed.

[0050] After the weight 111 is hung on the detection roller, if either the left voltage value Vl or the right voltage value Vr is equal to or greater than the span adjustment threshold value Vth2, it is determined that the weight 111 is hung on the detection roller, and the span adjustment value is stored.

[0051] For example, if the left-side voltage value Vl is equal to or greater than the span adjustment threshold Vth2, it is determined that the left-side tension detector 1L is connected to the tension control device 2, and then it is determined whether the right-side voltage value Vr is equal to or greater than the connection threshold Vth1. If it is determined that the right-side voltage value Vr is equal to or greater than the connection threshold Vth1, it is determined that the right-side tension detector 1R is connected to the tension control device 2, and it is determined that both the left-side tension detector 1L and the right-side tension detector 1R are connected to the tension control device 2, and the left-side voltage value Vl and the right-side voltage value Vr are stored as span storage values. Note that the order in which it is determined whether the left-side tension detector 1L or the right-side tension detector 1R is connected to the tension control device 2 does not matter.

[0052] Furthermore, if the right-side voltage value Vr is less than the connection threshold value Vth1, it is determined that only the left-side tension detector 1L is connected to the tension control device 2, and only the left-side voltage value Vl is stored as the span storage value.

[0053] Next, the zero adjustment process and span adjustment process in the tension control system 100 will be described in detail using a flowchart. Fig. 8 is a flowchart showing an example of the procedures for the zero adjustment process and span adjustment process in the tension control system according to the first embodiment. Fig. 9 is a conceptual diagram showing the relationship between the span adjustment time during span adjustment in the tension control system according to the first embodiment and the voltage value corresponding to the magnitude of the load signal. In Fig. 9, the horizontal axis shows the span adjustment time [s], which is the time during which the span adjustment is performed, and the vertical axis shows the voltage value [V] corresponding to the magnitude of the load signal acquired from the tension detector 1 during span adjustment.

[0054] To control the tension of the web material in a converting machine, the feed mechanism 3 is first stopped and the tension control device 2 is set to stop mode, and then a zero adjustment process and a span adjustment process are performed as a start-up process. The tension control device 2 is then switched to operation mode and controls the tension of the web material for the feed mechanism 3. The following process is performed with the feed mechanism 3 stopped and the tension control device 2 in stop mode.

[0055] First, in step S110, the zero adjustment process is started. The operator operates the operation unit 21 with no web material being hung on the feed mechanism 3, and inputs a tension calibration execution instruction to the operation unit 21 to instruct the execution of tension calibration for controlling the feed mechanism 3. The operation unit 21 transmits the tension calibration execution instruction to the processing unit 25.

[0056] When the processing unit 25 receives the tension calibration execution instruction, it enters zero adjustment mode and starts the zero adjustment process. In the zero adjustment process, the load signal acquisition unit 251 of the processing unit 25 acquires a left load signal and a right load signal as load signals from the tension detector 1.

[0057] Then, the load signal acquisition unit 251 converts the load signal acquired from the tension detector 1 into a voltage value corresponding to the magnitude of the load signal. The load signal acquisition unit 251 converts the left side load signal acquired from the tension detector 1 into a left side voltage value Vl, which is a voltage value corresponding to the magnitude of the left side load signal. The load signal acquisition unit 251 converts the right side load signal acquired from the tension detector 1 into a right side voltage value Vr, which is a voltage value corresponding to the magnitude of the right side load signal. Then, the process proceeds to step S120.

[0058] In step S120, the load signal acquisition unit 251 transmits information about the converted left-side voltage value Vl to the storage unit 23, and stores the left-side voltage value Vl as a left-side zero adjustment value. Then, the process proceeds to step S130.

[0059] In step S130, the load signal acquisition unit 251 transmits information about the converted right-side voltage value Vr to the storage unit 23, and stores the right-side voltage value Vr as a right-side zero adjustment value. That is, in steps S120 and S130, the zero adjustment value is stored in the storage unit 23. The zero adjustment value corresponds to the tare load of the detection roller. Then, the process proceeds to step S140.

[0060] In step S140, the span adjustment process is started. When the zero adjustment value is stored in the storage unit 23, the processing unit 25 automatically transitions to the span adjustment mode, and the determination unit 252 becomes active.

[0061] During span adjustment, as shown in Figure 4, an operator passes the string 110 wound around the unwinding roller 316 through the longitudinal center of each of the first roller 311, the second roller 312, the third roller 313, and the fourth roller 314, just as in the case of converting. The string 110 is passed over the second roller 312, which functions as a detection roller. Then, a weight 111 having a weight corresponding to the full-scale tension of the string 110 when converting is performed is hung from the tip of the string 110.

[0062] In the span adjustment process, the load signal acquisition unit 251 acquires a left load signal and a right load signal as load signals from the tension detector 1. The load signal acquisition unit 251 converts the load signals acquired from the tension detector 1 into voltage values ​​corresponding to the magnitude of the load signals. Then, the load signal acquisition unit 251 transmits information on the converted voltage values ​​to the determination unit 252.

[0063] That is, the load signal acquiring unit 251 converts the left side load signal acquired from the left side tension detector 1L into a left side voltage value Vl, which is a voltage value corresponding to the magnitude of the left side load signal. Then, the load signal acquiring unit 251 transmits information about the converted left side voltage value Vl to the determining unit 252. Also, the load signal acquiring unit 251 converts the right side load signal acquired from the right side tension detector 1R into a right side voltage value Vr, which is a voltage value corresponding to the magnitude of the right side load signal. Then, the load signal acquiring unit 251 transmits information about the converted right side voltage value Vr to the determining unit 252. Then, the process proceeds to step S150.

[0064] In step S150, the determination unit 252 determines whether the left side voltage value Vl is equal to or greater than a predetermined span adjustment threshold Vth2. As shown in Fig. 9, if the left side voltage value Vl is equal to or greater than the predetermined span adjustment threshold Vth2, the determination unit 252 determines that the left side load signal acquired from the left tension detector 1L is a load signal at a constant load. The hatched portion in Fig. 9 indicates the period during which it was determined that the load signal acquired from the tension detector 1L was a load signal at a constant load.

[0065] The span adjustment threshold Vth2 in embodiment 1 is a first threshold that is a threshold that the judgment unit 252 compares with a voltage value corresponding to the magnitude of the load signal acquired from the tension detector 1 in order to determine whether the load signal acquired from the tension detector 1 is a load signal at a constant load.

[0066] Furthermore, when the determination in step S150 starts, the determination unit 252 uses the timer function of the determination unit 252 to start measuring the time that has elapsed since the start of span adjustment, which is the span adjustment time.

[0067] If it is determined that the left side voltage value Vl is equal to or greater than the span adjustment threshold Vth2, the answer in step S150 is Yes, and the process proceeds to step S160. If it is determined that the left side voltage value Vl is not equal to or greater than the span adjustment threshold Vth2, the answer in step S150 is No, and the process proceeds to step S190.

[0068] In step S160, the determination unit 252 determines whether the right-side voltage value Vr is equal to or greater than a predetermined connection threshold Vth1. As shown in Fig. 9, the connection threshold Vth1 is smaller than the span adjustment threshold Vth2.

[0069] If it is determined that the right-side voltage value Vr is equal to or greater than the connection threshold Vth1, the answer in step S160 is Yes, and the process proceeds to step S170. If it is determined that the right-side voltage value Vr is not equal to or greater than the connection threshold Vth1, the answer in step S160 is No, and the process proceeds to step S180.

[0070] In step S170, the determination unit 252 transmits information about the right-side voltage value Vr to the storage unit 23, and stores the right-side voltage value Vr as a right-side span adjustment value, which is a span adjustment value. Then, the process proceeds to step S180.

[0071] In step S180, the determining unit 252 transmits information about the left side voltage value Vl to the storage unit 23, and stores the left side voltage value Vl as a left side span adjustment value, which is a span adjustment value.

[0072] In step S190, the determination unit 252 determines whether the right-side voltage value Vr is equal to or greater than a predetermined span adjustment threshold Vth2. As shown in Fig. 9, if the right-side voltage value Vr is equal to or greater than the predetermined span adjustment threshold Vth2, the determination unit 252 determines that the right-side load signal acquired from the tension detector 1 is a load signal at a constant load.

[0073] If it is determined that the right-side voltage value Vr is equal to or greater than the span adjustment threshold Vth2, the answer in step S190 is Yes, and the process proceeds to step S200. If it is determined that the right-side voltage value Vr is not equal to or greater than the span adjustment threshold Vth2, the answer in step S190 is No, and the process proceeds to step S230.

[0074] In step S200, the determination unit 252 determines whether the left-side voltage value Vl is equal to or greater than a predetermined connection threshold value Vth1.

[0075] If it is determined that the left side voltage value Vl is equal to or greater than the connection threshold Vth1, the answer in step S200 is Yes, and the process proceeds to step S210. If it is determined that the left side voltage value Vl is not equal to or greater than the connection threshold Vth1, the answer in step S200 is No, and the process proceeds to step S220.

[0076] In step S210, the determining unit 252 transmits the left voltage value Vl to the storage unit 23, and stores the left voltage value Vl as a left span adjustment value, which is a span adjustment value. Then, the process proceeds to step S220.

[0077] In step S220, the determining unit 252 transmits information about the right-side voltage value Vr to the storage unit 23, and stores the right-side voltage value Vr as a right-side span adjustment value, which is a span adjustment value.

[0078] In step S230, the determination unit 252 determines whether a predetermined non-connection determination time Tb has elapsed. The determination unit 252 uses a timer function of the determination unit 252 to determine whether the non-connection determination time Tb has elapsed.

[0079] The non-connection determination time Tb is a predetermined determination time for the determination unit 252 to determine whether both the left and right tension detectors 1 are not connected to the tension control device 2 and to determine the span adjustment value. A state in which both the left and right tension detectors 1 are not connected to the tension control device 2 means that both the left tension detector 1L and the right tension detector 1R are not connected to the tension control device 2.

[0080] If it is determined that the predetermined non-connection determination time Tb has elapsed, the result in step S230 is Yes, and the series of processes ends. If it is determined that the predetermined non-connection determination time Tb has not elapsed, the result in step S230 is No, and the process returns to step S150.

[0081] That is, if the determination unit 252 determines in step S230 that the unconnection determination time Tb has elapsed, it determines that both the left and right tension detectors 1 are not connected to the tension control device 2, and ends the span adjustment process. If the determination unit 252 determines in step S230 that the unconnection determination time Tb has not elapsed, it does not determine that both the left and right tension detectors 1 are not connected to the tension control device 2, and repeats the span adjustment.

[0082] According to the tension control device 2 of the tension control system 100 described above, a tension control device is realized that performs zero adjustment processing and span adjustment processing on a tension detector, and controls the tension of a long material transported by a feed mechanism based on the adjustment values ​​obtained by the zero adjustment processing and span adjustment processing.The tension control device is equipped with: a load signal acquisition unit that acquires a load signal indicating the tension of the long material from the tension detector; a determination unit that, when the zero adjustment processing is completed, transitions to a span adjustment mode that performs span adjustment processing, and determines that the load signal is a load signal at a constant load based on a voltage value corresponding to the magnitude of the load signal acquired by the load signal acquisition unit after the zero adjustment processing; and a setting unit that sets the voltage value corresponding to the magnitude of the load signal at the constant load determined by the determination unit as the span adjustment value.

[0083] As described above, in the tension control system 100, when the determination unit 252 of the tension control device 2 receives a tension calibration execution instruction, it enters zero adjustment mode, automatically performs zero adjustment processing, and stores the zero adjustment value in the memory unit 23. Then, when the zero adjustment value is stored in the memory unit 23, the determination unit 252 automatically transitions to span adjustment mode, automatically performs span adjustment processing, and stores the span adjustment value in the memory unit 23.

[0084] The operator operates the tension control device 2 to cause the tension control device 2 to start the zero adjustment process. After the zero adjustment value is stored in the memory unit 23, the operator moves to the feed mechanism 3 and performs the task of hanging the weight 111 from the roller of the feed section 31 of the feed mechanism 3. Then, once the zero adjustment value is stored in the memory unit 23, the tension control device 2 automatically transitions to span adjustment mode and performs processing.

[0085] In this way, in the tension control system 100, after hanging the weight 111 on the roller of the feed section 31 of the feed mechanism 3, the tension control device 2 automatically performs the span adjustment process without the operator having to operate the tension control device 2, and automatically acquires and stores the span adjustment value.

[0086] When performing span adjustment work using the tension control system 100, after the worker has hung the weight 111 during span adjustment, the worker can complete the span adjustment without moving from the side of the second roller 312, which functions as a detection roller in the feed section 31 of the feed mechanism 3.

[0087] As a result, with tension control system 100, the span adjustment work can be performed by one person, reducing the number of work steps. That is, with tension control system 100, the worker performing the span adjustment work does not need to repeatedly move between tension control device 2 and the roller of feed section 31 of feed mechanism 3 to perform the span adjustment work, reducing the burden on the worker.

[0088] Furthermore, when performing span adjustment work using a general tension control device, if the weight of the weight 111 is heavy, the worker cannot leave the roller of the feed section 31 for safety reasons, requiring two workers. However, with the tension control system 100, there is no need for a worker to operate the tension control device 2 after hanging the weight 111 from the roller of the feed section 31, and therefore the single worker who hangs the weight 111 from the roller of the feed section 31 can monitor the roller of the feed section 31, eliminating the need for two workers.

[0089] As described above, the tension control system 100 has the effect of reducing the burden on the operator and providing a tension control device that is easy to set up.

[0090] Embodiment 2 In Embodiment 2, other functions of the tension control system 100 described above will be described. In Embodiment 2, the determination method in the determination unit 252 differs from that in Embodiment 1. In Embodiment 2, if the voltage value corresponding to the magnitude of the load signal acquired from the tension detector 1 is equal to or greater than a predetermined threshold value and the fluctuation in the voltage value is within a predetermined range of determination values, the determination unit 252 determines that the load signal is a load signal at a constant load. The fluctuation in the voltage value can be said to be the fluctuation in the load signal acquired from the tension detector 1.

[0091] An overview of the span adjustment process of the tension control device 2 in embodiment 2 will be described. In embodiment 2 as well, before the weight 111 is suspended from the detection roller, neither the left voltage value Vl nor the right voltage value Vr becomes equal to or greater than the span adjustment threshold Vth2. Therefore, the processing unit 25 waits until either the left voltage value Vl or the right voltage value Vr becomes equal to or greater than the span adjustment threshold Vth2 and the left fluctuation range Vlf, which is the fluctuation range of the left voltage value Vl over the most recent predetermined range of time, becomes equal to or less than the predetermined load signal fluctuation range Vw, or until the non-connection determination time Tb has elapsed.

[0092] After the weight 111 is hung from the detection roller, if either the left voltage value Vl or the right voltage value Vr is equal to or greater than the span adjustment threshold Vth2 and the left fluctuation range Vlf, which is the fluctuation range of the left voltage value Vl in the most recent predetermined range time, is equal to or less than the predetermined load signal fluctuation range Vw, it is determined that the weight 111 is hung from the detection roller, and the span adjustment value is stored.

[0093] The zero adjustment process and span adjustment process of the tension control system 100 in embodiment 2 will be described in detail below using a flowchart. FIG. 10 is a flowchart showing an example of the procedure for the zero adjustment process and span adjustment process of the tension control system in embodiment 2. FIG. 11 is a conceptual diagram showing the relationship between the span adjustment time during span adjustment of the tension control system in embodiment 2 and the voltage value corresponding to the magnitude of the load signal. In FIG. 11, the horizontal axis shows the span adjustment time [s], which is the time it takes to perform the span adjustment, and the vertical axis shows the voltage value [V] corresponding to the magnitude of the load signal acquired from the tension detector 1 during span adjustment. Below, steps that differ from those in the flowchart shown in FIG. 8 in embodiment 1 will be described.

[0094] If it is determined in step S150 that the left side voltage value Vl is equal to or greater than the span adjustment threshold value Vth2, the answer in step S150 becomes Yes, and the process proceeds to step S310.

[0095] The span adjustment threshold Vth2 in embodiment 2 is a second threshold that is a threshold that the judgment unit 252 compares with a voltage value corresponding to the magnitude of the load signal acquired from the tension detector 1 in order to determine whether the load signal acquired from the tension detector 1 is a load signal at a constant load.

[0096] In step S310, the determination unit 252 determines whether the left side fluctuation width Vlf, which is the fluctuation width of the left side voltage value Vl within the most recent predetermined time range, is equal to or less than the predetermined load signal fluctuation width Vw. That is, the determination unit 252 determines whether the fluctuation of the left side voltage value Vl within the most recent predetermined time range is within the predetermined load signal fluctuation width Vw. As shown in Fig. 11 , if the left side fluctuation width Vlf, which is the fluctuation width of the left side voltage value Vl within the most recent predetermined time range, is equal to or less than the predetermined load signal fluctuation width Vw, the determination unit 252 determines that the left side load signal acquired from the tension detector 1 is a load signal at a constant load. The hatched portion in Fig. 11 indicates the period during which it was determined that the left side load signal acquired from the tension detector 1 was a load signal at a constant load.

[0097] The load signal fluctuation width Vw is a judgment reference value used by the judgment unit 252 to determine whether or not the load signal is a load signal at a constant load by comparing it with the fluctuation width of the voltage value corresponding to the magnitude of the load signal acquired from the tension detector 1, and is also a judgment reference value used to determine whether or not the weight 111 is hung from the second roller 312 that functions as a detection roller in the feed unit 31 of the feed mechanism 3.

[0098] If it is determined that the left fluctuation range Vlf of the left voltage value Vl in the most recent predetermined range of time is equal to or less than the predetermined load signal fluctuation range Vw, the answer in step S310 is Yes, and the process proceeds to step S160. If it is determined that the left fluctuation range Vlf of the left voltage value Vl in the most recent predetermined range of time is not equal to or less than the predetermined load signal fluctuation range Vw, the answer in step S310 is No, and the process returns to step S310.

[0099] If it is determined in step S190 that the right-side voltage value Vr is equal to or greater than the span adjustment threshold value Vth2, the answer in step S190 becomes Yes, and the process proceeds to step S320.

[0100] In step S320, the determination unit 252 determines whether the right fluctuation range Vrf, which is the fluctuation range of the right voltage value Vr in the most recent predetermined range of time, is equal to or less than the predetermined load signal fluctuation range Vw. That is, the determination unit 252 determines whether the fluctuation of the right voltage value Vr in the most recent predetermined range of time is within the range of the predetermined load signal fluctuation range Vw.

[0101] If it is determined that the right fluctuation range Vrf of the right voltage value Vr in the most recent predetermined range of time is equal to or less than the predetermined load signal fluctuation range Vw, the answer in step S320 is Yes, and the process proceeds to step S200. If it is determined that the right fluctuation range Vrf of the right voltage value Vr in the most recent predetermined range of time is not equal to or less than the predetermined load signal fluctuation range Vw, the answer in step S320 is No, and the process returns to step S320.

[0102] As described above, in the second embodiment, if the voltage value corresponding to the magnitude of the load signal acquired from the tension detector 1 is equal to or greater than the span adjustment threshold Vth2 and the fluctuation of the voltage value is within the range of a predetermined judgment reference value, the determination unit 252 of the processing unit 25 of the tension control device 2 determines that the load signal acquired from the tension detector 1 is a load signal at a constant load with the weight 111 suspended from the detection roller of the feed unit 31. This allows the processing unit 25 to perform span adjustment processing in a state where the vibration of the weight 111 suspended from the detection roller of the feed unit 31 has subsided and the fluctuation of the load signal is small, and calibration corresponding to the full-scale tension can be performed.

[0103] As a result, in the second embodiment, similar to the first embodiment, an effect is achieved in that a tension control device that reduces the burden on the operator and makes the setup work easy is obtained.

[0104] In the case of the first embodiment, a voltage value corresponding to the magnitude of the load signal obtained from the tension detector 1 immediately after the weight 111 is hung on the roller of the feed section 31 of the feed mechanism 3 is stored as a span adjustment value in the memory unit 23 of the tension control device 2. Here, depending on how the weight 111 is hung, the elasticity of the string 110 may cause the weight 111 to swing, which may result in an inaccurate load signal being obtained.

[0105] In contrast to this, in the second embodiment, if the voltage value corresponding to the magnitude of the load signal acquired from the tension detector 1 is equal to or greater than the span adjustment threshold Vth2 and the fluctuation of the voltage value is within a range of a predetermined judgment reference value, it is determined that the load signal acquired from the tension detector 1 is a load signal at a constant load in a state in which the weight 111 is suspended from the detection roller of the feed section 31. Therefore, in the second embodiment, the influence of vibration of the weight 111 during span adjustment can be reduced compared to the first embodiment, and the accuracy of the span adjustment is improved.

[0106] Embodiment 3 In embodiment 3, other functions of the tension control system 100 described above will be described. In embodiment 3, the determination method in the determination unit 252 differs from embodiment 1. In embodiment 3, if a voltage value corresponding to the magnitude of a load signal acquired from the tension detector 1 is equal to or greater than a predetermined threshold value and the period during which the voltage value is equal to or greater than the threshold value is equal to or greater than a predetermined determination time, the determination unit 252 determines that the load signal is a load signal at a constant load.

[0107] An overview of the span adjustment process of the tension control device 2 in embodiment 3 will be described. In embodiment 3 as well, before the weight 111 is suspended from the detection roller, neither the left-side voltage value Vl nor the right-side voltage value Vr becomes equal to or greater than the span adjustment threshold Vth2. Therefore, the processing unit 25 waits until either the left-side voltage value Vl or the right-side voltage value Vr becomes equal to or greater than the span adjustment threshold Vth2 and the period during which that voltage value remains equal to or greater than the span adjustment threshold Vth2 becomes equal to or greater than a predetermined determination time, or until the non-connection determination time Tb has elapsed.

[0108] After the weight 111 is hung from the detection roller, if either the left side voltage value Vl or the right side voltage value Vr is equal to or greater than the span adjustment threshold value Vth2 and the period during which the voltage value is equal to or greater than the span adjustment threshold value Vth2 is equal to or greater than a predetermined judgment time, it is determined that the weight 111 is hung from the detection roller, and the span adjustment value is stored.

[0109] The zero adjustment process and span adjustment process of the tension control system 100 in embodiment 3 will be described in detail below using a flowchart. FIG. 12 is a flowchart showing an example of the procedures for the zero adjustment process and span adjustment process of the tension control system in embodiment 3. FIG. 13 is a conceptual diagram showing the relationship between the span adjustment time during span adjustment of the tension control system in embodiment 3 and the voltage value corresponding to the magnitude of the load signal. In FIG. 13, the horizontal axis shows the span adjustment time [s], which is the time it takes to perform the span adjustment, and the vertical axis shows the voltage value [V] corresponding to the magnitude of the load signal acquired from the tension detector 1 during span adjustment. Below, steps that differ from those in the flowchart shown in FIG. 8 in embodiment 1 will be described.

[0110] If it is determined in step S150 that the left side voltage value Vl is equal to or greater than the span adjustment threshold value Vth2, the answer in step S150 becomes Yes, and the process proceeds to step S410.

[0111] The span adjustment threshold Vth2 in embodiment 3 is a third threshold that is a threshold that the judgment unit 252 compares with a voltage value corresponding to the magnitude of the load signal acquired from the tension detector 1 in order to determine whether the load signal acquired from the tension detector 1 is a load signal at a constant load.

[0112] In step S410, the determination unit 252 determines whether the period Tl, during which the left-side voltage value Vl is equal to or greater than the span adjustment threshold Vth2, is equal to or greater than a predetermined time threshold Tw. That is, the determination unit 252 determines whether the period Tl, during which the left-side voltage value Vl is equal to or greater than the span adjustment threshold Vth2, continues for equal to or greater than the predetermined time threshold Tw. As shown in FIG. 13 , if the period Tl, during which the left-side voltage value Vl is equal to or greater than the span adjustment threshold Vth2, is equal to or greater than the predetermined time threshold Tw, the determination unit 252 determines that the left-side load signal acquired from the tension detector 1 is a load signal at a constant load. The hatched portions in FIG. 13 indicate the periods during which it was determined that the left-side load signal acquired from the tension detector 1 was a load signal at a constant load.

[0113] If it is determined in step S150 that the left-side voltage value Vl is equal to or greater than the span adjustment threshold Vth2, the determination unit 252 starts measuring the period Tl using the timer function of the determination unit 252.

[0114] The time threshold value Tw is a judgment reference value used by the judgment unit 252 to determine whether or not the load signal is a load signal at a constant load by comparing it with the period Tl during which the voltage value corresponding to the magnitude of the load signal obtained from the tension detector 1 is equal to or greater than the span adjustment threshold value Vth2, and is also a judgment reference value used to determine whether or not the weight 111 is hung from the second roller 312 that functions as a detection roller in the feed unit 31 of the feed mechanism 3.

[0115] If it is determined that the period Tl during which the left voltage value Vl is equal to or greater than the span adjustment threshold Vth2 is equal to or greater than the predetermined time threshold Tw, then the answer in step S410 is Yes, and the process proceeds to step S160. If it is determined that the period Tl during which the left voltage value Vl is equal to or greater than the span adjustment threshold Vth2 is not equal to or greater than the predetermined time threshold Tw, then the answer in step S410 is No, and the process returns to step S410.

[0116] If it is determined in step S190 that the right-side voltage value Vr is equal to or greater than the span adjustment threshold value Vth2, the answer in step S190 becomes Yes, and the process proceeds to step S420.

[0117] In step S420, the determination unit 252 determines whether the period Tr during which the right-side voltage value Vr is equal to or greater than the span adjustment threshold Vth2 is equal to or greater than a predetermined time threshold Tw. That is, the determination unit 252 determines whether the period during which the right-side voltage value Vr is equal to or greater than the span adjustment threshold Vth2 has continued for equal to or greater than the predetermined time threshold Tw. If the determination unit 252 determines in step S190 that the right-side voltage value Vr is equal to or greater than the span adjustment threshold Vth2, the determination unit 252 starts measuring the period Tr using its timer function.

[0118] If it is determined that the period Tr during which the right-side voltage value Vr is equal to or greater than the span adjustment threshold Vth2 is equal to or greater than the predetermined time threshold Tw, then the answer in step S420 is Yes, and the process proceeds to step S200. If it is determined that the period Tr during which the right-side voltage value Vr is equal to or greater than the span adjustment threshold Vth2 is not equal to or greater than the predetermined time threshold Tw, then the answer in step S420 is No, and the process returns to step S420.

[0119] As described above, in the third embodiment, when the load signal acquired from the tension detector 1 is equal to or greater than the span adjustment threshold Vth2 and the period during which the voltage value is equal to or greater than the span adjustment threshold Vth2 is equal to or greater than the time threshold Tw, the determination unit 252 determines that the load signal acquired from the tension detector 1 is a load signal at a constant load when the weight 111 is suspended from the detection roller of the feed unit 31 of the feed mechanism 3. In other words, when the determination unit 252 determines that the voltage value corresponding to the magnitude of the load signal acquired from the tension detector 1 is equal to or greater than the span adjustment threshold Vth2, the determination unit 252 counts the period during which the voltage value is equal to or greater than the span adjustment threshold Vth2, thereby determining that the load signal acquired from the tension detector 1 is a load signal at a constant load when the weight 111 is suspended from the detection roller of the feed unit 31.

[0120] As a result, in the third embodiment, as in the second embodiment, the influence of vibration of the weight 111 during span adjustment can be reduced to perform span adjustment, and the accuracy of span adjustment is improved compared to the first embodiment.

[0121] In the second embodiment, when the determination unit 252 determines that the voltage value corresponding to the magnitude of the load signal acquired from the tension detector 1 is equal to or greater than the span adjustment threshold Vth2, and if the fluctuation in the voltage value falls within a range of predetermined determination reference values, the determination unit 252 determines that the load signal acquired from the tension detector 1 is a load signal at a constant load when the weight 111 is suspended from the detection roller. For this reason, the determination unit 252 needs to continue monitoring the voltage value corresponding to the magnitude of the load signal acquired from the tension detector 1.

[0122] In the third embodiment, when the determination unit 252 determines that the load signal acquired from the tension detector 1 is equal to or greater than the span adjustment threshold Vth2, the determination unit 252 measures the period during which the voltage value is equal to or greater than the span adjustment threshold Vth2, thereby determining that the load signal acquired from the tension detector 1 is a load signal at a constant load when the weight 111 is suspended from the detection roller of the feed unit 31. Therefore, in the third embodiment, the determination process of the determination unit 252 is simpler than in the second embodiment, and the load on the determination unit 252 is reduced. As a result, in the third embodiment, the design and implementation of the processing unit 25 are easier than in the second embodiment.

[0123] Embodiment 4 In embodiment 4, other functions of the tension control system 100 described above will be described. In embodiment 4, the determination method in the determination unit 252 differs from embodiment 1. In embodiment 4, when the difference between the voltage value corresponding to the magnitude of the load signal acquired from the tension detector 1 and the zero adjustment value acquired by zero adjustment is equal to or greater than a predetermined threshold, the determination unit 252 determines that the load signal is a load signal at a constant load.

[0124] An overview of the span adjustment process of the tension control device 2 in embodiment 4 will be described. In embodiment 4 as well, before the weight 111 is suspended from the detection roller, neither the left-side voltage value Vl nor the right-side voltage value Vr becomes equal to or greater than the span adjustment threshold value Vth2. Therefore, the processing unit 25 waits until the difference between the voltage value corresponding to the magnitude of the load signal acquired from the tension detector 1 and the zero adjustment value becomes equal to or greater than a predetermined threshold value, or until the non-connection determination time Tb has elapsed.

[0125] After the weight 111 is hung from the detection roller, if the difference between the voltage value corresponding to the magnitude of the load signal obtained from the tension detector 1 and the zero adjustment value is equal to or greater than a predetermined threshold value, it is determined that the weight 111 is hung from the detection roller, and the span adjustment value is stored.

[0126] The zero adjustment process and span adjustment process of the tension control system 100 in embodiment 4 will be described in detail below using a flowchart. FIG. 14 is a flowchart showing an example of the procedure for the zero adjustment process and span adjustment process of the tension control system in embodiment 4. FIG. 15 is a conceptual diagram showing the relationship between the span adjustment time during span adjustment of the tension control system in embodiment 4 and the voltage value corresponding to the magnitude of the load signal. In FIG. 15, the horizontal axis shows the span adjustment time [s], which is the time during which the span adjustment is performed, and the vertical axis shows the voltage value [V] corresponding to the magnitude of the load signal acquired from the tension detector 1 during span adjustment. Also, in FIG. 15, the zero adjustment value is shown as zero adjustment value V0. Below, steps that differ from the flowchart shown in FIG. 8 in embodiment 1 will be described.

[0127] After step S140, the process proceeds to step S510.

[0128] In step S510, the determination unit 252 determines whether the left-side differential voltage value Vldiff, which is the difference between the left-side voltage value Vl and the left-side zero adjustment value, is equal to or greater than a predetermined zero span adjustment threshold value Vth3. The left-side differential voltage value Vldiff is the differential voltage value Vdiff between the voltage value acquired from the tension detector 1 and the zero adjustment value.

[0129] The zero span adjustment threshold Vth3 is a judgment reference value used by the judgment unit 252 to determine whether the weight 111 is suspended from the second roller 312, which functions as a detection roller in the feed unit 31 of the feed mechanism 3, by comparing the difference between the voltage value corresponding to the magnitude of the load signal acquired from the tension detector 1 and the zero adjustment value. As shown in Fig. 15 , when the left side differential voltage value Vldiff is equal to or greater than the predetermined zero span adjustment threshold Vth3, the judgment unit 252 determines that the left side load signal acquired from the tension detector 1 is a load signal at a constant load. The hatched portion in Fig. 15 indicates the period during which it was determined that the left side load signal acquired from the tension detector 1 was a load signal at a constant load.

[0130] If it is determined that the left-side differential voltage value Vldiff is equal to or greater than the predetermined zero-span adjustment threshold Vth3, the answer in step S510 is Yes, and the process proceeds to step S160. If it is determined that the left-side differential voltage value Vldiff is not equal to or greater than the predetermined zero-span adjustment threshold Vth3, the answer in step S510 is No, and the process proceeds to step S520.

[0131] In step S520, the determination unit 252 determines whether the right-side differential voltage value Vrdiff, which is the difference between the right-side voltage value Vr and the right-side zero adjustment value, is equal to or greater than a predetermined zero span adjustment threshold Vth3. The right-side differential voltage value Vrdiff is the differential voltage value Vdiff between the voltage value acquired from the tension detector 1 and the zero adjustment value. As shown in FIG. 15 , if the right-side differential voltage value Vrdiff is equal to or greater than the predetermined zero span adjustment threshold Vth3, the determination unit 252 determines that the right-side load signal acquired from the tension detector 1 is a load signal at a constant load.

[0132] If it is determined that the right-side differential voltage value Vrdiff is equal to or greater than the predetermined zero-span adjustment threshold Vth3, the answer in step S520 is Yes, and the process proceeds to step S200. If it is determined that the right-side differential voltage value Vrdiff is not equal to or greater than the predetermined zero-span adjustment threshold Vth3, the answer in step S520 is No, and the process proceeds to step S230.

[0133] As described above, in the fourth embodiment, when the difference between the voltage value corresponding to the magnitude of the load signal acquired from the tension detector 1 and the zero adjustment value is equal to or greater than a predetermined threshold, the determination unit 252 determines that the load signal acquired from the tension detector 1 is a load signal at a constant load in a state in which the weight 111 is suspended from the detection roller of the feed unit 31 of the feed mechanism 3. This eliminates the need for the processing unit 25 to change the threshold each time tension calibration is performed.

[0134] In the first embodiment, the span adjustment threshold Vth2 is set to a constant fixed value, but since the load signal output from the tension detector 1 generally includes not only the load applied to the detection roller but also the weight of the detection roller, it is necessary to change the threshold value in accordance with the weight of the detection roller.

[0135] In contrast, in the fourth embodiment, the determination unit 252 determines that the load signal is a load signal at a constant load when the difference between the voltage value corresponding to the magnitude of the load signal acquired from the tension detector 1 during span adjustment and the zero adjustment value is equal to or greater than a predetermined threshold. Therefore, the determination by the determination unit 252 is based only on the load applied to the detection roller, and there is no need to change the threshold each time tension calibration is performed. For example, there is no need to change the threshold when tension calibration is performed after changing to a detection roller with a different weight.

[0136] Next, the hardware configuration of each of the control units 80 according to the first to fourth embodiments will be described. The control units 80 according to the first to fourth embodiments correspond to the mechanism control unit 33 of the feed mechanism 3, the detector control unit 14 of the tension detector 1, and the processing unit 25 and control unit 26 of the tension control device, respectively, according to the first to fourth embodiments. Each function of the control unit 80 according to the first to fourth embodiments is realized by a processing circuit. The processing circuit may be dedicated hardware, or may be a processing unit that executes a program stored in a storage device.

[0137] When the processing circuit is dedicated hardware, the processing circuit may be a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an application specific integrated circuit, a field programmable gate array, or a combination thereof. Figure 16 is a diagram showing a configuration in which the functions of the control unit according to the first to fourth embodiments are realized by hardware. The processing circuit 81 incorporates a logic circuit 81a that realizes the functions of the control unit 80.

[0138] When the processing circuit 81 is a processing device, the functions of the control unit 80 are realized by software, firmware, or a combination of software and firmware.

[0139] FIG. 17 is a diagram illustrating a configuration in which the functions of the control unit according to the first to fourth embodiments are realized by software. The processing circuit 81 includes a processor 811 that executes a program 81b, a random access memory 812 that the processor 811 uses as a work area, and a storage device 813 that stores the program 81b. The processor 811 deploys the program 81b stored in the storage device 813 on the random access memory 812 and executes it, thereby realizing the functions of the control unit 80. The software or firmware is written in a programming language and stored in the storage device 813. The processor 811 may be, but is not limited to, a central processing unit. The storage device 813 may be a semiconductor memory such as a random access memory (RAM), a read-only memory (ROM), a flash memory, an erasable programmable read-only memory (EPROM), or an electrically erasable programmable read-only memory (EEPROM). The semiconductor memory may be either a non-volatile memory or a volatile memory. In addition to semiconductor memory, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital Versatile Disc) can be used as the storage device 813. The processor 811 may output data such as calculation results to the storage device 813 for storage, or may store the data in an auxiliary storage device (not shown) via the random access memory 812. By integrating the processor 811, the random access memory 812, and the storage device 813 on a single chip, the functions of the control unit 80 can be realized by a microcomputer.

[0140] The processing circuitry 81 reads and executes the program 81b stored in the storage device 813 to realize the functions of the control unit 80. The program 81b can also be said to cause the computer to execute the procedures and methods for realizing the functions of the control unit 80.

[0141] The processing circuit 81 may be configured so that some of the functions of the control unit 80 are realized by dedicated hardware, and some of the functions of the control unit 80 are realized by software or firmware.

[0142] In this way, the processing circuitry 81 can realize each of the above-described functions by hardware, software, firmware, or a combination of these.

[0143] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or different embodiments may be combined with each other. It is also possible to omit or modify parts of the configurations as long as they do not deviate from the gist of the invention.

[0144] 1 Tension detector, 1L Left tension detector, 1R Right tension detector, 2 Tension control device, 3 Feeding mechanism, 4 Network, 11 Strain gauge type sensor, 12 Detector memory unit, 13 Detector communication unit, 14 Detector control unit, 21 Operation unit, 22 Display unit, 23 Memory unit, 24 Communication unit, 25 Processing unit, 26 Control unit, 31 Feeding unit, 32 Mechanism communication unit, 33 Mechanism control unit, 80 Control unit, 81 Processing circuit, 81a Logic circuit, 81b Program, 100 Tension control system, 110 String, 111 Weight, 251 Load signal acquisition unit, 252 Determination unit, 253 Setting unit, 254 Tension control unit, 311 First roller, 312 Second roller, 313 Third roller, 314 Fourth roller, 315L Left bearing, 315R Right bearing, 316 Unwinding roller, 317 winding roller, 811 processor, 812 random access memory, 813 storage device, Tb disconnection determination time, Tl, Tr period, Tw time threshold, Vdiff differential voltage value, Vl left side voltage value, Vldiff left side differential voltage value, Vlf left side fluctuation range, Vr right side voltage value, Vrdiff right side differential voltage value, Vrf right side fluctuation range, Vth1 connection threshold, Vth2 span adjustment threshold, Vth3 zero span adjustment threshold, Vw load signal fluctuation range.

Claims

1. A tension control device that performs zero adjustment processing and span adjustment processing of a tension detector, and controls the tension of a long material transported by a feed mechanism based on the adjustment values ​​obtained by the zero adjustment processing and the span adjustment processing, comprising: a load signal acquisition unit that acquires a load signal indicating the tension of the long material from the tension detector; a determination unit that, when the zero adjustment processing is completed, transitions to a span adjustment mode that performs the span adjustment processing, and determines that the load signal is a load signal at a constant load based on a voltage value corresponding to the magnitude of the load signal acquired by the load signal acquisition unit after the zero adjustment processing; and a setting unit that sets the voltage value corresponding to the magnitude of the load signal at the constant load determined by the determination unit as a span adjustment value.

2. The tension control device according to claim 1, wherein the determination unit determines that the load signal is a load signal at a constant load when the voltage value is equal to or greater than a predetermined first threshold value.

3. A tension control device according to claim 1 or 2, characterized in that the judgment unit judges that the load signal is a load signal at a constant load when the voltage value is equal to or greater than a predetermined second threshold value and the fluctuation of the voltage value is within a range of a predetermined judgment reference value.

4. A tension control device according to any one of claims 1 to 3, characterized in that the determination unit determines that the load signal is a load signal at a constant load when the voltage value is equal to or greater than a predetermined third threshold value and the period during which the voltage value is equal to or greater than the third threshold value is equal to or greater than a predetermined determination time.

5. A tension control device according to any one of claims 1 to 4, wherein the determination unit determines that the load signal is a load signal at a constant load when the difference between the voltage value and the zero adjustment value acquired by the zero adjustment process is equal to or greater than a predetermined threshold value.

Images