8521-LC-MT  冗余控制器可用于关键控制应用

冗余控制器可用于关键控制应用。冗余控制器对并行运行，通过处理回路多次检查状态，使备份控制器能够持续监控主控制器的健康状况，确保快速无颠簸地转移到备用控制器。
网络冗余
除了控制器冗余，MOST逻辑控制器有两个高速以太网端口，以提供通信的安全性。每个端口都可以连接到一个独立的局域网，该局域网将持续监控其完整性。如果主端口检测到网络故障，流量立即切换到另一个局域网，以保持充分的通信。
可执行控制程序
控制程序保存在非易失性存储器中，使它们能够在控制器电源循环后自动恢复。使用冗余控制器还可以使新的控制程序下载到备用单元，同时该过程继续进行。当下载完成并验证后，待机状态可以切换到主状态以使用新程序。
远程Modbus设备
MOST逻辑控制器通过以太网上的Modbus TCP进行通信，可以在Modbus Master或Modbus Slave模式下与远程Modbus设备进行通信。每个控制器还有2个串行端口，可以配置为Modbus Master，以控制和获取Modbus slave和其他串行设备的信息，如秤，条形码阅读器等。串行端口也可以配置为Modbus Slave，接受来自Modbus Master设备的写命令，并在其数据寄存器上提供信息。
故障安全和自动冷启动
在完全失去通信的情况下，控制器将采用用户定义的failsafe模式，并类似地指示I/O采用用户定义的failsafe值。在断电的情况下，MOST逻辑控制器将执行冷重启，恢复程序并假定预定义的状态。
点对点通信
大多数控制器之间都可以进行点对点通信，使控制器之间能够共享数据。这种功能确保了关键信息可以在控制器之间有效地共享，而不是要求数据从控制室传递到每个控制器。
I/O模块配置
MOST逻辑控制器接收其控制下的所有I/O模块的详细信息，并将信息存储在非易失性存储器中。在启动时，控制器将其配置细节下载到模块，其中还包括在通信失败时应该采用的故障安全状态。
固件更新
为了保持其在连续基础上维持操作的能力，冗余MOST逻辑控制器也能够接收固件升级。通过与策略更新类似的方式，控制器可以在现场接收到对其固件的更新。当确认升级成功后，控制器可以作为主控制器或保护备用控制器完全恢复运行。

8521-LC-MT

Redundant controllers can be used for critical control applications. The redundant controller pair operates in parallel, checking status multiple times through the processing loop enabling the backup con-troller to continuously monitor the health of the master controller, assuring a rapid and bumpless transfer to the standby controller.
Network redundancy
In addition to controller redundancy, the MOST Logic Controller has two high-speed Ethernet ports to provide security of communication. Each port can be connected to an independent LAN which is continuously monitored for its integrity. If the primary port detects a network failure, traffic is immediately switched to the other LAN to maintain full communication.
Executable control programs
The control programs are held in nonvolatile memory to enable them to be restored automatically after power cycling of the controller. The use of a redundant controller also enables a new control program to be downloaded to the standby unit while the process continues. When the download has been completed and verified, the standby can be switched to master status to employ the new program.
Remote Modbus Devices
The MOST Logic Controller communicates via Modbus TCP over Ethernet and can operate in either Modbus Master or Modbus Slave mode to communicate with remote MODBUS devices. Each controller also has 2 serial ports that can be configured as a Modbus Master to control and obtain information from Modbus Slaves and other serial devices, such as weighscales, barcode readers, etc. The serial ports can also be configured as a Modbus Slave, accepting write commands from Modbus Master devices and providing information on its data registers.
Failsafe and automatic cold start
In the event of complete loss of communication the controller will adopt a user-defined failsafe mode and similarly instruct the I/O to take up user-defined failsafe values. In the event of power loss the MOST Logic Controller will perform a cold restart which restores the program(s) and assumes a predefined status.
Peer to peer communications
MOST Logic Controller can communicate with each other on a peer to peer basis, enabling controllers to share data with each other. This capability ensures that critical information can be efficiently shared between controllers instead of requiring data to be passed to each controller from the control room.
I/O module configuration
The MOST Logic Controller receives full details of all the I/O modules under its control and stores the information in nonvolatile memory. At start-up the controller downloads to the modules their configuration details, which also include the failsafe states they should adopt in the event of communication failure.
Firmware updates
In keeping with its ability to maintain operations on a continuous basis, a redundant MOST Logic Controller is also capable of receiving a firmware upgrade. In a manner similar to that used for strategy updates, a controller can receive an update to its firmware while in the field. When the upgrade has been confirmed as successful, the controller can be returned to full operation as a master or as a protective standby.