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Chapter 6 Introduction to GPP Software I. Basic Overview SW3D5-GPPW-E is a programming software developed by Mitsubishi Electric for programmable controllers. It can run on Windows 3.1 and Windows 95, and is suitable for IBM PC/AT (compatible) systems with a CPU of i486SX or higher. The required memory is 8 MB or more (16 MB or more is recommended). This program can communicate with programmable controllers in serial systems, enable file transfer, perform operation monitoring, and offer various testing functions. In GPP software, you can create sequencer instruction programs using line symbols and mnemonics, establish annotation data and set register values, and save them as files for printing. An interface unit and cables must be present between the PLC and the PC. Interface unit: FX-232AWC type RS-232C/RS-422 converter (portable). FX-232AW type RS-232C/RS-422 converter (built-in). Cable: FX-422CAB type RS-422 cable ； FX-422CAB-150 RS-422 cable [for FX1, FX2, FX2C programmable controllers, 1.5 meters.] II. Writing ladder diagrams using GPP: The GPP software is flexible, simple, and easy to use. We install it in the program; to use it, one simply enters the program, selects MELSEC Applications → GPP running under WINDOWS, opens a new project, and selects “New”. The screen shown in Figure 5-1 appears then. First, select the CPU series of the PLC model you are using – in our experiment, we used the FX series, so we selected FXCPU. The PLC type refers to the model of the machine; since we used the FX2N series in our experiment, we selected FX2N(C). After confirmation, the screen shown in Figure 5-2 appears. On this screen, it is clear that the far left side represents the main busbar. The blue frame indicates the area where data can be written. There is a menu at the top; by clicking on any element in this menu, one can access the coils, contacts, etc., needed. Figures 5-1 and 5-2: If you want to enter X000 at a certain location, simply move the blue cursor to the place where you want to type it, then select “Contact” from the menu. This will result in the display shown in Figure 5-3. Figure 5-3: Enter X000 once more, and thus the value X000 will be entered. To enter a timer, first select the coil, then input some data. The standards for entering this data are mentioned in Chapter 3, and Figure 5-4 shows the procedure for doing so. Figure 5-4 shows that for a counter, since it sometimes requires two input terminals, both the input coil section and the reset section need to be activated in order for it to function; the operation process is illustrated in Figures 5-5 and 5-6. Figure 5-5: Note that in the area indicated by the arrow in Figure 5-5, what is selected are the application instructions, rather than the coils. Figures 5-6 illustrate the usage method of the counter and its counting range, which were covered in Chapter 3; students can refer to it on their own. Figure 5-7 is a simple counter display format. Figure 5-7: Through the examples above, students can understand that if they need to draw other lines, output contacts, timers, counters, auxiliary relays, etc., in a ladder diagram, they can easily find them in the menu and then enter the component numbers. Above Figures 5-6, there are several other function menus. If you move the cursor to a particular item on the menu, its function will be displayed in the lower left corner of the screen. Alternatively, by selecting “Help” on the menu, you can find a list of shortcuts, information on special relays/registers, and more. Students can learn and practice on their own. III. Transmission and Debugging: After writing the ladder diagram and adding the END statement at the end, it is necessary to convert the program. There are two buttons for this conversion function, located at the positions indicated by the arrows in Figure 5-8. Figure 5-8 shows that during the program conversion process, if there are errors in the program, they will be displayed; the correctness of the program can also be checked through the “Tools” menu. Program transfer can only be carried out after the ladder diagram has been converted. Before transferring, the switch on the FX2N panel must be set to the STOP position; thereafter, the “Online” menu should be opened to make the transfer settings, as shown in Figure 5-9. As indicated in Figure 5-9, you need to determine whether your PLC is connected to the computer via COM1 or COM2. In this experiment, we connected the RS-232 cable to the computer’s COM1 port, and all you need to do is make the corresponding selection during operation. After writing the ladder diagram, still select “Online” from the menu and choose “Write to PLC (W)”. As shown in Figure 5-9, it can be seen from this figure that MAIN and PLC parameters must be selected first before reading and writing; otherwise, reading or writing to the program cannot be performed. After that, click “Start Execution”.