Doc ID : ADR241A_IM_01
Ref ID : ADR241A/IM/CS
Rev No. : 02
Page No. : 83 of 150
ADR141A /
7 COMMUNICATIONS
7.1 MODBUS
This section describes how the MODBUS standard is applied to the ADITYAV2 platform. It is
not a description of the standard itself. The level at which this section is written assumes that
the reader is already familiar with the MODBUS standard.
The MODBUS protocol is a master/slave protocol, defined and administered by the
MODBUS Organization. For further information on MODBUS and the protocol specifications
please see the Modbus web site (
www.modbus.org).
Overview: Physical Connection and Link Layer
For connecting on MODBUS use:
Rear serial port - for permanent SCADA connection via RS422/RS485
The MODBUS interface uses ‘RTU’ mode communication rather than ‘ASCII’ mode as this
provides more efficient use of the communication bandwidth. This mode of communication is
defined by the MODBUS standard.
The IED address and baud rate can be selected using the front panel menu
When using a serial interface, the data format is: 1 start bit, 8 data bits, 1 stop bit (a total of
10 bits per character).
7.1.1 MODBUS Protocol Map
7.1.1.1 Function Codes supported
Code Function Name Addresses starts with
02 Read Input Status 1x addresses
03 Read Holding Registers 4x addresses
04 Read Input Registers 3x addresses
05 Force Single Coil 0x addresses
16 Preset Multiple Registers 4x addresses
7.1.1.2 Exception Codes generated in case of an error
Code
MODBUS Response
Name
Product interpretation
01 Illegal Function Code The function code received in query is not supported by the IED.
02 Illegal Data Address The start address received in the query is not an allowable value.
NOTE: If the start address received is correct but the range includes
unsupported address this error is produced.
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