Communication between Siemens S7-200 and expansion modules
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What could be the reason for no communication between the Siemens S7-200 and the expansion modules? I have checked the communication cables and they seem to be fine; however, a communication failure occurred over time. I hope experts can help me figure out what the cause is
If the DP indicator and other lights do not light up, check the power supply
The third expansion module still shows a communication error even after power is supplied; I’ve tried supplying power to it
The voltage is normal; the issue lies in the inability of the CPU to communicate with the expansion modules, which is likely related to the 485 communication protocol. I’m not sure whether there’s a setting for the communication address in the CPU’s program. Please help me analyze this, experts
The voltage is normal; the issue lies in the inability of the CPU to communicate with the expansion modules, which is likely related to the 485 communication protocol. I’m not sure whether there’s a setting for the communication address in the CPU’s program. Please help me analyze this, experts
Use the substitution method and try replacing the expansion module
The CPU of your PLC seems to be an original Siemens product, while all the modules connected to it are domestic replicas; it’s not surprising then that there are issues such as unstable communication or other problems! What else is there to check? Change it! ! !