Modbus Protocol Overview; The Transmission Format - ABB IM300-I Operational Manual

At the bottom of this screen displays the system time and the format is "hour:
minute: second", see in Fig 3-6-2.
The system time is: 02: 41: 50.
.
Screen 3：Temperature of device
At the bottom of this screen displays the
temperature of device, see in Fig 3-6-3.
The temperature of device is: 25.8℃
Screen 4：Time Format 3
At the bottom of this screen displays the system time
and the format is "year: month: day", see in Fig 3-6-4.
The system time is: 2008-02-20.
Screen 5：No display
At the bottom of this screen displays nothing.
4. Communication

4.1. MODBUS protocol overview

MODBUS-RTU communication protocol is more commonly used as a
communication protocol, the response from the main station and the slave station
connection (half duplex).
the terminal devices (for example IM300), The addressed terminal device sends a
response signal to the host.

4.1.1 The transmission format

Information is transmitted asynchronously and in bytes. The communication
message passing between the main station and the slave station is the 11-bit word
IM300 Intelligent Power Monitoring Instrument
Themain station (for example PC) send a command to all
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Fig 3-6-3 Device temperature
Fig 3-6-4 Time Format 3