Modbus Remote Communication Protocol; 1.Protocol Overview - ABB REM 610 Technical Reference Manual

1MRS 752263-MUM
4.1.14.
4.1.14.1.
Motor protection Relay
Technical Reference Manual
Table 4.1.13-2 Information mapping of configuration set 1 and 2
Measurand
Current I 2.40
L1
Current I 2.40
L2
Current I 2.40
L3
Current I 2.40
0

Modbus remote communication protocol

Protocol overview
The master/slave protocol Modbus was first introduced by Modicon Inc. and is
widely accepted as a communication standard for industrial device controllers and
PLCs. For the protocol definition, refer to "Modicon Modbus Protocol Reference
Guide PI-MBUS-300 Rev. E".
The implementation of the Modbus protocol in REM 610 supports both the RTU and
the ASCII link mode. Both the link mode and the line setting parameters are
user-configurable.
The character codings of the link modes follow the protocol definition. The RTU
character format is presented in table 4.1.14.1-1 and the ASCII character format in
table 4.1.14.1-2:
Table 4.1.14.1-1 RTU character format
Coding system
Bits per character
Table 4.1.14.1-2 ASCII character format
Coding system
Bits per character
Note!
The turnaround time (response time) of REM 610 depends on the amount of data
requested in a query. Therefore, the turnaround time can vary between
approximately 10 and 70 milliseconds. However, a turnaround timeout no lower
than 100 ms is recommended for the Modbus master.
I X X
n
I X X
n
I X X
n
I X X
n
8-bit binary
1 start bit
8 data bits, the least significant bit is sent first
1 bit for even/odd parity; no bit if parity is not used
1 stop bit if parity is used; 2 stop bits if parity is not used
Two ASCII characters representing a hexadecimal
number
1 start bit
7 data bits, the least significant bit is sent first
1 bit for even/odd parity; no bit if parity is not used
1 stop bit if parity is used; 2 stop bits if parity is not used
REM 610
135 140 9
65