Mitsubishi PLC programming notes - Database & Sql Blog Articles

One of the very useful features of Mitsubishi plc programming software is that it can be written in the same program according to different control object classifications. This makes the program structure clearer and easier for program communication.

In the following example program, according to the different control loops, the program is divided into several loop programs, such as alarm loop, indication loop, inverter control loop, communication loop and protection loop, although the program is still executed sequentially, but It is easier to read and communicate because the relevant programs of the same control object are placed in the same program.

The way to build a classification program is simple. First, just right click on any of the items, and then select "New" in the pop-up window, as shown below:

In the pop-up "New" window, select the program type, data name and index, as shown below:

But when we write a new program (even if there is only one MAIN project) or add a new program project in the original program, we should pay attention not to download the new program project to the PLC. If you simply do this, although there is a new project in the CPU, the PLC does not scan and execute the program. Of course, the program will not have any output (the PLC input can still be monitored when monitoring the program). In the process of this paragraph, there may be a phenomenon as shown in the following figure. Although there is input, but the output coil does not move, it may be a bit incomprehensible.

The solution to this phenomenon is to introduce the newly added program project into the scanning process of the PLC. The specific method is as follows:

1. Double-click "PLC Parameters" in the PLC Project Manager.

2. In the pop-up "CPU Parameter Settings" window, click the "Programs" tab, then click on the newly added program item in the program list on the left, click "Insert", and finally specify the program item. "Execution type".

3. After the addition, the result is as shown in the figure below. Finally, click “End Settings” to save, and then download the PLC parameters to the CPU.

Sometimes the online modification program does not allow shutdown, and the download PLC parameters must be downloaded in the shutdown state. How to solve this problem?

My solution is: write the program to the program that the PLC has scanned and executed, so the readability may be almost the same. You can also add the interline statement in the first line of the newly added program, indicating that it is new. Add the program, as shown below, so that you do not need to stop the program when downloading programs and statements.