A small question regarding the Modbus RS 485 communication baud rate
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There are already two complete sets of equipment (Siemens S7 200) in a corner of our company, which communicate with the DCS via a communication cable. Now another set of equipment has been added there as well, and it is also controlled by a PLC. Since running new communication cables would be quite difficult, I would like to enable the newly added PLC to communicate with the DCS using the existing communication cable (in read-only mode, without control functions). However, the baud rate of this new PLC is 19200, while the baud rates of the existing two PLCs are 9600. Is it possible to do this? Or should the baud rate of the new PLCs also be set to 9600? The station numbers for the three PLCs are all different. Can any experts who have done this before help me resolve my doubts?
Modify the baud rate and communication protocol to be the same. The station number should be distinct from the first two.
When using Modbus RS485 communication, all devices communicating on the same network must have the same baud rate. Therefore, if you want to add a new PLC to the existing system via the existing communication cables, you need to set the baud rate of the new PLC to 9600, so that it matches the baud rate of the two existing Siemens S7 200 PLCs. Furthermore, it is correct to ensure that the station numbers of the three sets of PLCs are all different, so as to avoid address conflicts. At the same time, it is technically feasible for the new PLC to perform only reading operations without control, as long as the data transmission configuration is correct. In short, by adjusting the baud rates to match and setting the station numbers and communication parameters, you should be able to meet your requirements. .
Okay. Then I’ll ask the manufacturer to change it to be the same