Members of the training team encountered a problem during the competition: After completing the PLC project and the touch screen, they were able to download it to the hardware, but pressing the buttons on the touch screen would trigger an error message. The students were unable to resolve this issue on-site, and after the competition, they recreated the project on their own computer, using PLCSIM for simulation debugging, but pressing the button still resulted in an error. The teacher believed there was a configuration issue, so they tried again, adding the touch screen device under the project created by the students, and created an indicator light and a button on the touch screen. The indicator light was animated to connect to the PLC’s 1Hz clock, and the button event was connected to the PLC’s M2.0. After downloading the project, the indicator light on the touch screen flashed normally, but pressing the button still triggered an error, as detailed below:
In the same project, with the same touch screen device, a normally open M2.0 contact was written to control an M3.0 coil. After re-downloading the project and simulating the debugging, pressing the touch screen button no longer resulted in an error, and pressing the button could change the state of M3.0.
In the same project, a new touch screen was added with the same configuration and operation method, and pressing the button also did not trigger an error.
The teacher used the same operation method to create a project on another computer, and there were no errors.
The models of the PLC, touch screen, and TIA Portal are as follows:
PLC: S7-1200 1215 DC/DCDC
Touch Screen: TP700
TIA Portal: V16
[Summary]
1. When this issue occurred, a new rung of a pulse control ladder diagram was written and re-downloaded without changing the button event connections or other settings on the touch screen, and the problem was resolved, with no further errors.
2. Once this issue was resolved, adding other touch screen devices under this project, deleting the pulse control ladder diagram, and using the same method to add buttons did not result in errors.
3. If the error issue is not resolved, re-adding the touch screen device in the same project using the same method, or having someone else perform the configuration, will still encounter this error.
4. Using the same method, the same person operating on different computers did not encounter the error issue.
5. It is suspected that there is a problem with the PLC configuration created by the student, but it is unclear why adding a rung of the ladder diagram resolved the issue during debugging.
6. The student recreated the project on the same computer using the same method for configuration and download, and did not encounter any issues.