CIRCUTOR CEM-M-ETH - Manual (Page 13)

Table 5 shows the format of the MODBUS/TCP frame.
Table 5: MODBUS/TCP frame format
Name Length Function
Transaction identifier 2 For message synchronisation between the server and client.
Protocol identifier 2 Value 0 for MODBUS/TCP
Field length 2 Number of bytes remaining in the frame
Unit identifier 1 Peripheral number
Function code 1 Modbus function number
Data bytes n Response or command data
The MODBUS functions implemented in the unit are:
Functions 03 and 04. Reading of logs.
Function 10. Writing of multiple logs.
4�4�2�- VARIABLES MODBUS
All MODBUS map addresses are hexadecimal.
4�4�2�1�- Configuration variables
The Read and Write functions are implemented for these variables.
Table 6:Modbus configuration variables CEM M-RS485.
Description Address Size Valid data range
Default
value
Impulse output type 0x0080 16 bits 0: Active energy, 1: Reactive energy 0
Impulse output weight 0x0081 16 bits Wh/impulse 0 ... 99999 -
Cost per kWh 0x00B0 32 bits
0.0000 ... 9999.9999 with 4 decimal places
of resolution
-
KgCO
2
0x00B2 32 bits
0.0000 ... 9.0000 with 4 decimal places of
resolution
-
Note: Some MODBUS variables may not be available depending on the CEM energy meter
coupled to the CEM M-ETH. See “4.4.2.7.- Available addresses by unit”
13 Instruction Manual
CEM M-ETH