Touch screen and plc communication parameter setting and communication failure solution

Any touch screen on the market can’t communicate with plc usually, just need to confirm four questions:
1. Whether the plc parameters are consistent with those in the project
2. Whether the communication line is in accordance with the wiring diagram Pin wiring
3. Whether the com port set in the project is correct when connected on the screen
4. If the parameters and lines are confirmed to be OK, check whether it is the PLC program or the PLC address problem.
Method:
(Judge the parameters first:) 1. Use the PLC programming software to connect to the PLC to test to see what the parameters of the PLC are, and whether the parameters set in the project are consistent with those tested.
2. On-line simulation: Use our configuration software, connect the PLC itself to the computer with the communication cable, and perform online simulation to see if the project is in communication. You can use a numerical input component or switch to operate it, and see if the previous operation is still there after turning off the simulator and then opening the online simulation, and whether it directly prompts the NC. (If NC and the previous operation are not written down, it means that it is not connected)
(Test line): Use a multimeter to test the wiring according to the pin definition in the wiring diagram.

1: Touch screen parameters. Check the parameter settings of the touch screen.
There are a few parameters that need special attention.
1: Communication port setting—————————Be sure to confirm clearly whether the PLC is connected to the COM1 or COM2 port of the touch screen.
2: Equipment Type – – – – – – – – – – – – – – – – – – – this is the most important, if the protocol is not selected correctly, other needless to say
3: Connection method – – – – – – －－－－－－－－－－－－－——The connection between PLC and touch screen, confirm the RS485 or RS232C
4: Interface parameters and PLC station number－－－－－－－－－－－－－－－－ ——Must be consistent with the settings in the PLC.
Two: If the parameters are confirmed to be set, then check the line problems.
Confirm whether the wiring of RS485 and RS232C is correct. The touch screen and various PLC wiring methods are different. This can be viewed by referring to Weikong (the help document for the connection method of PLC and touch screen communication lines)
This is the basic method for normal troubleshooting of communication problems.
Next, I will teach you how to bypass the problem of the touch screen — online simulation.
When the communication fails, some customers may guess that it may be a problem with the touch screen or the interface.
Online simulation is to bypass the touch screen and directly connect the PLC with the computer.
Specific methods:
1: PLC and computer should be connected through RS232. Some PLCs have RS232 interfaces, some do not, and some can be connected to the computer through an adapter.
2: Create a new profilesingle project. Put two components, one for numerical display and one for numerical input. Address Set the address inside the PLC.
3: The project parameter settings must be the same as those in the PLC.
4: Click on the online simulation function
In this way, you can clearly check whether the PLC can communicate with the PC. If you can communicate, you can rule out PLC problems and parameter setting problems.