Definition
Modbus is the most widespread and oldest open communication protocol for exchanging data between industrial devices. It comes in two forms: Modbus RTU runs over an RS485 serial line with dozens of devices on one cable; Modbus TCP does the same over Ethernet. A master (PLC, SCADA or gateway) reads and writes values at addresses called registers in slave devices (energy analysers, drives, meters, temperature controllers). It is simple, licence-free and present in almost every device, which makes it the fastest way to start monitoring an existing plant. It has no security, so a Modbus network must be kept separate from the outside world.
How SMB Teknoloji uses it
We connect existing drives, analysers and meters to the monitoring system by reading them over Modbus RTU/TCP; our Pompalog field device reads up to 120 Modbus RTU channels.