Modbus Remote Communication Protocol - ABB REM 610 Technical Reference Manual

REM 610 REM 610
5.1.14.
74
Motor Protection Relay
Technical Reference Manual - ANSI Version
Table 5.1.13.-2 Information mapping of configuration set 1 and 2
Measurand
Current l
a
Current l
b
Current l
c
Current I
n

Modbus remote communication protocol

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 Section 1.4. Product documentation.
The implementation of the Modbus protocol in the relay 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 5.1.14.-1 and the ASCII
character format in Table 5.1.14.-2:
Table 5.1.14.-1 RTU character format
Coding system 8-bit binary
Bits per 1 pickup bit
character 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
Table 5.1.14.-2 ASCII character format
Coding system Two ASCII characters representing a hexadecimal number
Bits per 1 pickup bit
character 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
The turnaround time (response time) of the relay depends on the
amount of data requested in a query. Therefore, the turnaround time
can vary between approximately 10 and 70 ms. However, a turnaround
timeout no lower than 100 ms is recommended for the Modbus master.
2.4 I (CT) X X
n
2.4 I (CT) X X
n
2.4 I (CT) X X
n
2.4 I (CT) X X
n
1MRS755537
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