ABB RELION REF610, Technical Reference Manual

Page: 88 / 176

Table 5.1.15.-1 RTU character format
Coding system 8-bit binary
Bits per
character 1 pickup 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
Table 5.1.15.-2 ASCII character format
Coding system Two ASCII characters representing a hexadecimal number
Bits per
character 1 pickup 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
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 20 and 100 ms. However, a
turnaround timeout no lower than 150 ms is recommended for the
Modbus master.
The data address range in the Modbus network follows the protocol
definition and starts from 0. Consequently, the data addresses in
Table 5.1.15.1.-5...Table 5.1.15.1.-13 are decreased by one when
transferred over the network.
The Modbus data type digital input (DI) is commonly also referred to
as 1X, coils as 0X, input register (IR) as 3X and holding register (HR)
as 4X, of which the former is used here. Thus, HR 123, for instance,
can also be referred to as register 400123.
5.1.15.1. Profile of Modbus
The Modbus protocol (ASCII or RTU) is selected via the HMI and can be used only
through the rear connection of the relay on the optional communication module.
Modbus line settings, that is, parity, CRC byte order and baud rate, can be adjusted
either via the HMI or the SPA bus.
The implementation of the Modbus protocol in REF610 supports the following
functions:
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REF610 REF610 Feeder Protection Relay
Technical Reference Manual - ANSI Version
1MRS755535