Issues with Siemens S7-300 programs

The last edit to this post was made by Sichuan Instrument Control Beginner on 2015-8-7 at 22:16. When working with S7 300 programs, two things need to be taken into account: 1. The communication method between the PC and the PLC; 2. Whether the program currently open is the one in use. First, you should have Step7 software installed on your computer. Go to Start – Programs – Siemens – Simatic – Simatic Manager. Once the program is running, you can click on “File” in the menu to view the programs that have been opened recently; select the topmost one (hoping it’s the correct program). Then click on “Options” – “Set PC/PG Interface” to open the communication settings dialog box, and choose the appropriate communication method based on your actual setup. Once selected, it will be online (the small glasses on the toolbar indicate that it is online). The tree-shaped bar on the left can be expanded level by level, with detailed sub-items appearing on the right accordingly. If sub-items such as OB, DB, FC, etc. are seen, then these are the PLC programs. The PLC program starts with OB0 by default. Double-clicking on OB0 allows you to view its logic; it’s possible that all of the program logic is contained within this OB0. OB0 may also call other FC programs. After opening the program, there is a magnifying glass icon on the toolbar that enables you to view the program online. If the PC has a different program than the PLC, you can upload the program. You can refer to this document: http://wenku.baidu.com/view/096a421a10a6f524ccbf8587.html. Belt stoppage is usually caused by signals such as thermal relays, on-site switches, pull cords, belt deviation, blockages, slippage, or feedback related to the belt’s operation (and these may be just some of the factors). The equipment on site might experience brief interruptions due to environmental conditions; if the program does not include a delay mechanism for judgment, this can result in so-called \"secret stoppages\". If the program variables are not annotated, you will need to refer to the wiring diagram and then guess the meaning of the intermediate variables. Good luck.