How does DCS identify signals sent via MODBUS? And how does it identify them when several devices are connected in series?
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How does DCS identify signals sent via MODBUS, and how does it identify them when several devices are connected in series?
According to the specifications for the Modbus master module, it’s fine to connect up to 30 slaves.
In simple terms, it involves using software or hardware to set the addresses of various devices, after which the master station communicates with each one in turn through polling
Primary address, secondary address. Slave addresses under different primary addresses
First, one needs to understand the MODbus protocol, which is determined by the slave address.
The DCS requires a communication card; communication with Yokogawa and Heima has just been established
Both the master and slave stations have unique addresses, and registers also have addresses; that’s how they can be distinguished from each other
This determines which device it is through the device address
A card that supports this protocol is required; multiple devices are assigned different addresses through hardware DIP switches in order to distinguish them as field devices
Set different addresses and read in a polling manner
Each slave station has a slave address; communication is possible as long as the baud rate is correct, the verification is proper, and the slave address is accurate