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2020
EVO/
™ECM-Modbus RTU
Series 2
Page 24
Application Guide
©2020 All Rights Reserved
Evolution Controls Inc.
San Diego, CA USA
ADDRESSING
The EVO/ECM-Modbus RTU responds to polls at four different addresses.
Global Address
Modbus RTU protocol defines address 0 as a global address. All RTUs on
the trunk respond to writes the Modbus RTU Master issues to address 0.
None of the EVO/ECM-Modbus RTUs reply.
Unit Address
Each EVO/ECM-Modbus RTU must be assigned a unique address. The
Modbus RTU Master uses this address when communicating with only that
RTU.
Group Address 1
The Modbus RTU Master may communicate with a group of EVO/ECM-
Modbus RTUs having the same group1 address. None, or only one of the
RTUs in the group will reply. A trunk may have as many different group 1
addresses as are required for the application.
Group Address 2
The Modbus RTU Master may communicate with a group of EVO/ECM-
Modbus RTUs having the same group 2 address. None, or only one of the
RTUs in the group will reply. A trunk may have as many different group 2
addresses as are required for the application.
The EVO/ECM-Modbus RTU facilitates two group addresses
because applications may need overlapping groups.
