Rockwell Automation AADvance Controller Configuration Guide - Manual (Page 209)

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Document: 553633
ICSTT-RM405f-EN-P
Issue 07
9-23
Choosing Names for Modbus Objects
The Modbus object Name identifies a Modbus master object or slave link within the
AADvance Workbench, and is included in printed reports; but it is not used by the
application. We recommend that you use a different name for each object.
Alternatively, accept the default name.
Modbus Master Timeout
The Modbus master Timeout is common to all slaves configured to a particular
master. It specifies the period of time the Modbus master will wait for a response from
its slave device(s) before retrying or assuming that the slave is unavailable. The Modbus
master uses the timeout for each of its configured slaves to determine whether they
are still communicating. If a slave does not respond within this period (and a specific
number of retries), it will be deemed to have failed.
Note: You configure the number of retries independently for each slave.
Message Wait Interval
The Message Wait Interval enables the Modbus master to support legacy Modbus
slave devices, with slow communications responses, attached to multi-drop serial links.
It is used only for serial Modbus communications using Modbus RTU.
The interval provides time for a legacy slave device to establish that a response from
another slave to an earlier request from the Modbus master is not a new request
targeted to the legacy slave. The illustration shows a multi-drop link from the Modbus
master to two slave devices, with the request message to slave 2 delayed by the
message wait interval.