Ch ap te r 3 Down lo ading a nd Mo nitor ing th e Pr ogr am3.3 Monitoring and Debugging the Program3.3.1 Monitoring the ProgramWhen the program is executed, users can monitor the program to understand the current logicalcontrol state, or modify the values in some devices to test the system. The operation of the programmonitoring is as follows.z Monitoring the programOpen the Prog_Main window, and click .Not only the logic program, but also the information related to the devices is monitored. (If thedata type is a Boolean value, the state of the device is represented by green (ON) or white(OFF). If the data type is not a Boolean value, the value in the device is shown.)If users want to alter the value in the device, they can click the right mouse button.Tank_B1F_LSW is the device which is modified here. Please notice that the device correspondsto an actual I/O device. Setting the device to ON or OFF is meaningless because the actual I/Ovalue covers the setting value immediately. To alter the value in the device, users need to forcethe device ON or OFF.The value in the device is altered, and a lock symbol indicating that the device is forced ONappears.3 - 9