13EN
COUNTIS E23/E24 - 545877A - SOCOMEC
8.3. Communication structure
The device communicates via a Modbus protocol which involves a dialogue in accordance with a master/slave
structure. The communication mode is the RTU (Remote Terminal Unit) mode with hexadecimal characters composed
of at least 8 bits.
Modbus frame structure (master -> slave question):
Slave address Function code Address Number of words to be
read
CRC 16
1 byte 1 byte 2 bytes 2 bytes 2 bytes
To comply with the Modbus protocol, the inter-character time must be ≤ 3 silences.
This means the time for 3 characters to be emitted so that the message is processed by the COUNTIS E23/E24.
In order to use the information correctly, you must use the Modbus functions in accordance with the codes:
• 3: to read n words (maximum 128).
• 6: to write one word.
• 16: to write n words (maximum 128).
N.B.:
1 word <=> 2 bytes <=> 16 bits
2 words <=> 4 bytes <=> 32 bits
The broadcast communication is available for the log that stores the tariff.
8.4. Communication tables
The communication tables and relevant notes are available on the
COUNTIS E23/E24 documentation page on the website at the
following address:
www.socomec.com/en/countis-e2x