Redundant Hardware Configuration
Consideration must be given to connection of the redundant LC modules to the field
devices. Devices designed for redundancy often have two independent serial ports.
In this case, each Ovation LC module is connected to one of the serial ports.
Some multi-drop serial networks can accommodate multiple masters. In this case,
the two LC modules could be connected to the one network by using the RS-485
Group 2 personality module. Consult the field device manufacturer’s
documentation to determine the appropriate connection.
5-5. LC/Modbus Interface Redundancy Operation
Ovation LC/Modbus Interface redundancy involves coordinating the data flow
between the Ovation Controller and the Ovation LC modules and enabling/
disabling communication between each module and the field devices.
Redundancy is driven by the Ovation Controller in that the Controller decides which
module should transfer data and which module should communicate with the field
devices. The Controller bases these decisions on feedback from each module about
the state of the communication.
A redundant LC/Modbus link uses SLC algorithms to move data to and from the LC
module just as a non-redundant link does, but with these exceptions:
• The algorithms which transfer data to the LC module (that is, SLCAOUT and
SLCDOUT) must be repeated for the secondary LC, because these algorithms
cannot transfer data to both cards simultaneously.

冗余硬件配置
必须考虑冗余LC模块与现场的连接
设备。为冗余设计的设备通常有两个独立的串行端口。
在这种情况下，每个Ovation LC模块都连接到一个串行端口。
一些多点串行网络可以容纳多个主机。在这种情况下，
两个LC模块可以通过RS-485连接到一个网络
第二组人格模块。请咨询现场设备制造商
确定适当连接的文档。
5-5. LC/Modbus接口冗余操作
Ovation LC/Modbus接口冗余涉及协调数据流
在Ovation控制器和Ovation LC模块之间，并启用/
禁用每个模块与现场设备之间的通信。
冗余由Ovation控制器驱动，控制器决定
模块应传输数据，以及哪个模块应与现场通信
设备。控制器根据来自每个模块的反馈做出这些决定
沟通的状态。
冗余LC/Modbus链路使用SLC算法在LC之间移动数据
模块与非冗余链路一样，但有以下例外：
•将数据传输至LC模块的算法（即SLCAOUT和
由于这些算法
无法同时向两张卡传输数据。