Rockwell Automation T8xxx Trusted Communications Interface - Manual (Page 22)

Trusted
TM
Communication Interface T8151B
Issue 21 Apr 10 PD-T8151B 22
3.4.3. SOE over Modbus: Requirements
In order to use SOE over Modbus, there are several configuration steps that must be taken.
 At least one Modbus Slave must be configured and active in order to use the SOE over
Modbus service.
 Configure variables for SOE logging. Variables should have the “Enable SOE Logging”
extended attribute set (or be connected to a SOE board) and have a valid Modbus address.
 Configure the SOE Over Modbus service. Each communication module that will support the
service must be configured. Redundant configurations must be defined with the same
information.
 Resolve Modbus address conflicts. The Modbus addresses specified by the Address Window
must be unique, and not defined by the application except for certain addresses in redundant
configurations.
 Define Modbus addresses for Redundant Configurations. For redundant configurations across
communication modules, the first 4 addresses in the SOE Address window should be defined
by the application, but not used elsewhere.
 Configure the Modbus Master. Ensure the Modbus Master is configured with the appropriate
addresses, and has implemented the SOE Over Modbus protocol.
3.4.4. SOE over Modbus: Redundant Configurations
The SOE over Modbus service runs independently on each Communications Interface module on
which it is configured. While the service on each module will provide the same event data, the
presentation of that data to a Modbus master is not normally synchronized. The service can be used in
a redundant, fail-over configuration by taking the following steps.
 Each Communication Interface module that is to be a part of the redundant configuration must
be configured for SOE over Modbus using the same values for the Base Address and Block
Count.
 In the Toolset, 4 integer variables must be defined in the dictionary and assigned a Modbus
address that corresponds to the first 4 addresses in the SOE Address Window, starting at the
address defined by the Base Address field. These variables will be used by the SOE over
Modbus services on each communication module to synchronise the presentation of event
data.