Mashallah ,, That was best video I have ever watched about the ModeBus. Thanks very much. AjarakAllah. If u could, please give some example how to send these data by PLC to the slaves.
Both are the communication protocols can be transferred over the same physical layer of OSI model via electrical standard RS485. Both works on the Master slave type protocol. With the RS485 physical layer both can communicate upto distance of 1200 meter You can use unit ID of save from 1-247 in both the protocols. There are many more similarities. Both the different protocols, they may works better from each other in different applications
Sure, here are the answers to your questions: 1. The Modbus function code used in the request from the master to read several registers of the slave is 0x03, which is the Read Holding Registers function code. 2. The address of the first register to read in the master query is 0x0202. 3. The number of registers to read in the master query is 0x0258, which is 600 in decimal. 4. To decode the Modbus message sent by the slave, we can break down the message into its different parts: Slave Address: 0x04 - This indicates that the message is intended for slave device with address 0x04. Function Code: 0x03 - This indicates the function code used in the request, which is 0x03 for Read Holding Registers. Starting Address: 0x0202 - This is the address of the first register to be read by the master. Number of Registers: 0x0258 - This is the number of registers to be read by the master. CRC: 0xDE74 - This is the Modbus CRC value for error checking. To answer the question "What is the request sent by the Modbus master to read the slave registers from the address of departure 00 64?", we can convert the decimal value 100 (which is 0x64 in hexadecimal) to a Modbus address, which would be 0x0064. Thus, the request sent by the Modbus master would be: Slave Address: 0x04 Function Code: 0x03 Starting Address: 0x0064 Number of Registers: 0x0258 (600 in decimal) CRC: Calculated by the master based on the request message. Show less
sir one confusion , if function code is defined as 04 for input registers and data address as 30001~40000, then how can the input register 30004 represent the function code 3 for input register as mentioned at 20:21
