Abstract: Taking the control object of the oscillating motor in the etching cavity of the shadow mask etching line as the object, B&R's PCC and ACOPOS servo controllers are used to control the motion of the synchronous motor, so that the motor in the oscillating cavity can quickly and stably follow the set curve and move according to the set curve. The PVI in the PCC allows the PCC to communicate with the host computer for easy communication; PowerLink enables real-time and fast communication between servos; the high-level programming language C of the PCC enables the PCC to complete advanced applications that traditional PLCs cannot do, such as curve generation; and the introduction of the virtual axis concept further improves the reliability of motor operation. 1 Introduction 1.1 System Introduction The system is a common groove shadow mask etching line, mainly including an uncoiling section, an etching cavity section, a first water washing section, an electrolytic stripping section, a final water washing section, and a final drying and tearing section. The coiled steel strip with photoresist on the surface is pulled open in the uncoiling section and fed into the etching cavity. The etching solution in the cavity is FeCl3, which reacts with the non-photoresist part of the steel strip to form grooves. The first water wash stops the etching process and completely removes the FeC13 from the shadow mask surface evenly. The stripping section is used to strip the photoresist from the steel strip surface, and the stripping solution is NaOH. The final water wash removes the NaOH and impurities from the steel strip surface. The drying section dries the moisture on the steel strip surface to prevent rusting. Afterward, the steel strip enters the edge-tearing machine to tear off the waste edges around the shadow mask. The etching process is shown in Figure 1. [align=center] Figure 1 Etching Production Line Process[/align] The etching chamber is the key part of the entire system, and its etching effect directly affects the product qualification rate. The entire etching process has 6 chambers, each with two pairs of nozzles, one above the other, controlled by two motors. The motors control the nozzles to swing back and forth. Therefore, the entire etching section consists of 12 motors. Since the motors swing back and forth continuously, they are called swing motors. 1.2 Introduction to the Swing Motor Movement According to the process requirements, the motors must run along a certain trajectory, and different motors have different running trajectories. Due to the high requirements for the running curve, the control of the swing motors used B&R's PCC and ACOPOS servo controllers. [align=center]Figure 2 Swing Motor Track Point Settings[/align] On the host computer, the operator sets 16 points on a trajectory, as shown in Figure 2, where the horizontal axis represents position and the vertical axis represents speed. Each of the 12 motors has a set curve. In addition to performing logic control such as starting, stopping, and running the motors, the main function of the PCC is to control the motors to move along a certain trajectory, so that the trajectory simultaneously passes through the 16 set points, and to ensure smooth motor operation. Due to the requirement for fast response and high control precision, synchronous servo motors are used for motion control of the swing section. Previously, a Toshiba PLC was used, which had the problem of uneven swing, so the high-performance controller PCC developed by B&R was used instead. The PCC uses an embedded operating system in the controller, and the device layer network adopts real-time Ethernet, which can achieve very high real-time control requirements. 2. B&R PCC and ACOPOS Servo 2.1 B&R PCC Hardware Configuration The swing section uses the B&R 2005 CPU. The 2005 series CPU is B&R's fourth-generation control system SG4, using an Intel processor, and includes a power module, CPU module, and digital input/output module. A Power Link network adapter is inserted into the CPU's PCI bus slot. If PowerLink is used for serial connection, a maximum of 10 servo controllers can be connected in series. This system uses a Power Link IF786 and a HUB to divide the 12 motors into two serial branches for real-time control. The digital input module is used for start, stop, emergency stop, Readay, and origin finding signal input for the 12 motors. The digital output is used for motor operation, motor fault, and origin finding status indication for the 12 motors. The host computer and PCC can communicate via RS232 and Ethernet. RS232 is used as the programming port. Ethernet is used as the real-time communication port for data upload and download. The motion curve set by the host computer is transmitted to the PCC in real time, and the actual motion position, speed, current, and fault information are also transmitted to the host computer. [align=center]Figure 3 Servo Controller and Peripheral Connections[/align] Figure 3 shows the connection diagram of a motor's servo controller with other hardware devices. The motor controller uses a B&R ACOPOS servo controller. The servo controller is connected to a Power Link module AC112 for connection with the front and rear servo controllers; AC122 is a rotary encoder module used for motor speed and position detection. The ACOPOS 1090 itself provides temperature signal detection (T+, T-), brake signal output (B-, B+), and other control signals. In the field, three optocouplers are installed to set the forward limit position, reverse limit position, and origin position of the motor. Before operation, the motor first finds the position of the origin optocoupler and sets it to the 0 position, and then runs according to the set curve. The forward and reverse limit optocoupler signals play a protective role. When the optocoupler gives a signal, the servo will give a limit fault information and stop operation. 2.2 ACOPOS Servo Control Method [align=center] Figure 4 Servo Control Block Diagram [/align] The servo control of ACOPOS is shown in Figure 4, which can be roughly divided into four parts: initial value processing, position control, speed control, and actual value detection. In the initial processing, based on the given position, maximum allowable speed, and maximum allowable acceleration, an ideal positioning process is given, that is, the acceleration, constant speed, and deceleration segments are obtained, and the speed at different positions is also obtained accordingly. Position control mainly includes proportional adjustment, proportional adjustment limit p_max, integral limit i_max, and integral adjustment. The value after proportional adjustment is k*Δs. If k*Δs>p_max, then v_p P_max; if k*Δs 3 B&R PCC Software System The entire software system can be divided into the Process Visualization Interface (PVI) and Automation Studio. PVI is used for communication with the host computer, while Automation Studio is used for programming the logic control and motion control of PCC. 3.1 PVI Communication PVI is the unified interface for all Windows applications to access B&R industrial controllers. Using PVI, users don't need to spend a lot of time considering the underlying communication process when developing communication programs, nor do they need to call complex and cumbersome Winsock API functions. They only need to perform simple configuration on the logical structure to access variables on the PCC. The biggest feature of PVI is its ability to directly manipulate variables in PCC tasks using the program. Therefore, a unique path must be specified for the mapping of each process variable in the PVI Manager. The core task of PVI communication is to establish the mapping of process variables, resulting in each mapping corresponding one-to-one with a unique variable in the network. This variable can be a basic data type, such as an integer variable, or a user-defined data type, such as a structure variable. This mapping contains path information from the workstation where the application resides to the task where the variable resides. If controllers and modules are also considered objects in the communication, each mapping path includes the following objects: basic object (Pvi); line object; station object; CPU object; module object; task object; and variable object. This mapping path is managed uniformly by the PVI Manager, and each object contains an object name, object description, and access parameters. The object name (including the path) is the name in the PVI. The object name is arbitrarily determined by the user, and the object description must be the same as the variable name to be mapped in the PCC. The PVI Manager relies on the object description to find the specific process variable and realize the mapping relationship. Access parameters include data type description, refresh time, event type, etc. In this system, the speed of the servo motor running at 16 positions is determined. The position and speed can be set on the host computer and then sent to the PCC. Encapsulate these data into a structure: struct MotorCommset { float Position [16]; // Position of 16 points float Speed ​​[16] ; // Speed ​​of 16 points int MotorNumber ; // Indicates which motor is currently set } ; 3.2 Automation Studio Programming Automation Studio provides a variety of programming methods for each application and program. These include: Ladder Diagram (LAD), Instruction List (IL), Structure Text (ST), Sequential Function Chart (SFC), AB, and ANSIC. Among them, ANSIC is a powerful high-level programming language used in the new generation of Automation Studio. More advanced functions can be achieved using languages ​​written in ANSI C. In the motor control of the swing section, ANSI C is used to generate curves. 3.2.1 Object Creation B&R's servo motion control adopts an object-oriented control method. After creating an application object `ax_obj` for a servo controller using the high-level C language, different motion controls can be performed on the motor using the pointer `p_ax_dat_` created for this motion object. `ncalloc(ncACP10MAN+ncPOWERLINK-IF,ACP10 NONE,ncAXIS,l,(UDINT)&ax_obj);` Each servo controller has a node setting section in its hardware, which can be configured to indicate that the slave axis and master axis are synchronized at a 1000:1000 ratio. B&R provides a dedicated channel for uploading and downloading servo parameters, called the SERVICE channel. Through the SERVICE channel, both single parameters and parameter blocks can be transmitted. After downloading "autogear" as a parameter block to the server via the SERVICE channel, the relationship between the virtual axis and the real axis is established. strcpy(& DataDownload .parameter.data_modul [0], "autogear") // The filename to be downloaded p_ax_dat_>network.service.data_adr ﹦(UDINT) & DataDownload // Service channel ncaction (ax_obj,ncACP_PAR+ncSERVICE,nc-DOWNLOAD ) // Virtual axis and real axis setting download Once the relationship between the master axis and the slave axis is established, as long as the virtual axis parameter is operated, the real axis will follow the virtual axis position 1:1 synchronously. The operation of the virtual axis parameter can also be performed through the SERVICE channel. p_ax_dat_> network.service.request.par_id =ACP10PAR_CMD_POS_MOVE_VAX1 // Parameter to be assigned p_ax_dat_> network.service.data_adr = (UDINT) & par_dat // Parameter value ncaction(ax_obj, ncSERVICE, ncSET) // Parameter setting 3.2.3 Program Design The program is shown in Figure 5. It is mainly divided into two parts: one is the overall logic control part, which is completed by ladder diagram; the other is the motion control part, which is completed by C language. [align=center] Figure 5 Program Flowchart[/align] When finding the origin, the motor runs in the positive direction. If the origin signal is received, it stops and is set to 0; if the positive limit signal is received, it stops and then runs in the opposite direction. When the origin signal is found, it is set to 0. The curvilinear motion is a subroutine where uniform acceleration occurs between points. The acceleration is switched on the imaginary axis based on position. 4. Design Results Communication with the host computer was achieved using the PVI of B&R's PCC. Ladder diagrams were used for logic control of start-up, stop, and fault handling. The high-level C language was used to implement the curve manipulation. Furthermore, during the curvilinear motion, speed and position signals were transmitted to the host computer in real time, facilitating real-time observation and adjustment of the curve. Currently, the entire production line has been put into trial production, and the etching effect is good. Figure 6 shows the real-time motion curve of the servo motor. After finding the origin by moving in the forward direction, the servo motor starts moving to the given point. Uniform acceleration is used between adjacent points, and the acceleration of each curve segment is changed according to the position. During operation, the host computer randomly samples the actual position and speed of the motor and displays the sampled points on the host computer interface. After a period of time, the actual trajectory of the motor can be seen. As shown in the figure, the motor passes through the set points during actual operation. The required error in the manufacturing process was 2mm, while the actual design yielded an error of only 0.5mm, significantly improving performance. Even at high speeds, such as 40 cycles per minute, the motor remained stable, whereas the manufacturing process only required 15 to 30 cycles. [align=center]Figure 6: Actual Application Curve of the Servo Motor[/align] The use of B&R's PCC made communication, control, and motion more convenient, flexible, and reliable. B&R's PVI function facilitated communication, making it a separate task. Power-Link enabled real-time and rapid control and transmission between the PCC and 12 servos. The high-level C language of the PCC facilitated curve generation. Furthermore, the unique virtual axis concept of B&R further ensured smooth and reliable motor operation.