Function Codes In Modbus communication, function codes are a core issue, with each function code representing the action to be executed by the message. The commonly used function codes are defined as follows: Function Code Name Purpose 01 (0x01) Read Coils Read the status of one or more coils 02 (0x02) Read Discrete Inputs Read … Read more
When I first started programming in C, I was full of hope to quickly master this powerful programming language, imagining that I could write efficient code like those programming experts. However, reality hit me hard; every time I confidently pressed the compile and run button, eagerly anticipating a perfectly running program, I was instead met … Read more
Special register functions used in MODBUS/TCP communication.Used to store the latest error codes SD10130-SD10137 for the built-in Ethernet.Indicator light status displays communication status:When MODBUS communication is functioning normally, both LED indicators will light up. If the LEDs are not lit, check the wiring or the settings and error status of the master and slave stations. … Read more
How to determineif a Modbus TCPconnection is established? Answer: To performModbus TCPcommunication, a connection must be established. S7-200 SMART CPUas aModbus TCPclient: You can determine the connection status using the Modbus TCP Client instruction’s symbol table parameter mConnected, as shown in Figure 1. If mConnected=1, it indicates that the connection has been established, while mConnected=0 … Read more
Common HTTPError Codes Sometimes we encounter a situation where a website cannot be accessed, and it returns some error codes. Some common error codes include: 404, 503. Tips 4xx (Client Error) These status codes indicate that there may be an error with the request, preventing the server from processing it. 400 (Bad Request) The server … Read more