Not only because the speed, but for the simple compatibility with our main tools, the computers…Įach automation brand have their own protocol based on Ethernet (Profinet, Ethernet/IP, Ethernet Powerlink, etc…).
Industrial Ethernet has become the last 10 years as the replacement for the serial communication.
Now you have seen all the required steps to configure a powerful data exchange between a Master PLC and up to 32 Modbus slaves with just a few program code lines, enjoy it!
Here you have the programs of the Master PLC and both Slaves and also a pdf where you can find which registers you have to configure in order to read/write each one of the 32 Slaves. On the slave’s side, we only have to configure the communication (ASCII/RTU, baudrate, data bits, parity, stop bits) and a different node number to each slave.
Let’s take as an example an application where we want to communicate with first slave (ID1) and a second one over the 16 standard slaves, the 20 th (ID20) for instance, at the end of this post you’ll find the example programs to be downloaded on the Master and in the two slaves.įirst of all, we have to be sure that the communication parameters are the same on all the nodes connected to the Modbus (ASCII/RTU, baudrate, data bits, parity,stop bits) and also that all have a different node number.
Write up to 100 words (16 bits variable) to each slave.Read up to 100 words (16 bits variable) from each slave.Using the DVP12SE PLC (fw versions 1.6 and above) you will be able to: Today I would like to show you how our PLC DVP12SE ( Link) is able to overcome this limitations and increase the number of slaves and the number of data to be exchanged. Write up to 50 words (16 bits variable) to each slave.Read up to 50 words (16 bits variable) from each slave.In general, the PLC Link feature is limited to: Slaves can be PLC, drives, temperature controller and, in general, any equipment that includes and RS485 Modbus port.įor those who don’t know this feature here you can find other posts in this blog with detailed information:Įxchange between Master PLC and Slave drive (VFD):Įxchange between Master PLC and Slave PLC:Įxchange between Master PLC and Slave temperature controller:
Probably some of you already know the PLC Link feature of our DVP series PLCs, it allows us to easily exchange data between the master PLC and several slaves saving a lot of programming time.