Chapter 3 Downloading and Monitoring the Program 3.3.2 Debugging the Program and the System When the system operates, an error may occur, and the error LED indicator on a module may be ON. If an error occurs, and the error LED indicator is not ON, the error is a logic program error. If users follow the steps in the example, no error will occur. In order to demonstrate a system error, users are asked to turn off the 24 V DC power supply. After the 24 V DC power supply is turned off, the bus fault LED indicator on the CPU module and the error LED indicator on AH06XA-5A are ON. Click in the window at the left side of the main screen of the software, and then click .
The actual statuses of the modules are as follows. Generally speaking, a hardware configuration error occurs if the BUS FAULT LED indicator on the CPU module is ON. Users can select AH06XA-5A, click the right mouse button, and select Diagnosis . The information about the error is shown in the following picture. As the picture above shows, the module is not supplied with power. Please turn on the power supply, and click Refresh . The system will check the status of the module again. In this example, the module has been supplied with power. Therefore, the system does not detect any error, and there is no error log in the Current box, as shown below.
If the system detects a new error, the new error log appears in the Current box. Besides, the error log in the History box is cleared if users click Clear . However, due to the fact that the modules are designed differently, the error logs are not maintained 3-13