The MODBUS communication protocol was created by Modicon, however, due to its numerous advantages, it has become
standard accepted by many manufacturers of automation devices. The protocol sets out the rules for the exchange of information between two or
many devices. MODBUS ensures the fastest possible data transfer (eg by grouping information about the contents of registers and sending only one starting address), while checking if they have been misrepresented. The organization of communication between devices is based on a simple principle that one Master device (Pan) called also a client is superior and the rest is slave type (slave) otherwise called servers.
Such an organization organizes the rules of occupying the link, and in combination with error signaling, it protects against the suspension of communication.
The MODBUS protocol exists in two versions – earlier ASCII and later RTU. For practical reasons, the following information applies
RTU and RTU Extended.
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