ABB PM891 3BSE053240R1 提供通信扩展总线（CEX总线）
PM866-2 3BSE050201R1
PM864AK01
PM825 3BSE010796R1
PM510V16 3BSE008358R1
PM891是一种高性能控制器，能够处理应用程序
要求很高。
PM891通过光学模块连接到S800 I/O系统。它可以行动
作为独立的过程控制器，或作为执行本地控制任务的控制器
在控制网络中。
两个PM891控制器可以作为一对冗余控制器一起工作，其中一个为PM891
用作主控制器，而另一个用作备用控制器。备份
如果在
主控制器。
通过两个内置IEEE802.3以太网实现控制网络连接
PM891上的通道。
PM891还提供通信扩展总线（CEX总线）
可以连接多个扩展模块。这些模块提供连接
适用于各种现场总线和I/O系统。在冗余对的情况下，两者
PM891连接到同一CEX总线，其中一个可以控制
模块。
物理上，PM891处理器单元包括：
•电源和状态信号连接器（L+、L-、SA、SB）。
•用于电气CEX总线的DB25连接器。
•外部电池连接器。
•用于两个以太网通道的RJ45连接器。
•一个通信端口。
•用于连接最多七个集群的Optical Modulebus连接器，
具有12个非冗余或6个冗余模块（即7x12=84个模块）。
•冗余链路连接器。
•SD（安全数字）存储接口。
•LED。
•按钮复位开关
处理器单元冗余可用于PM861、PM864、PM865、PM866和
PM891。在这种情况下，控制器包含两个处理器单元，每个处理器单元包括
用于系统和应用软件的存储器。一个单元作为主要单元
另一种是备份（热备用）。主处理器单元控制该过程。这个
备用设备随时待命，准备在主设备出现故障时接管。这个
切换在不到10ms的时间内顺利完成。在切换过程中
过程输出被冻结。
转换后，系统作为一个没有冗余的系统运行
只有一个处理器单元在工作。您可以更换出现故障的处理器
单元，而系统正在运行。更换后，系统
再次具有冗余处理器单元。
如果备份单元出现错误，您也可以在
系统正在运行。
备份单元中发生的错误永远不会影响主单元的运行。
主单元和备份单元在逻辑上彼此分离。
主处理器单元中的硬件错误导致系统执行正确的
转换。这些硬件错误是单个错误。
应用程序编程和通信完全不受
冗余
PM891 is a high performance controller, which is capable of handling applications
with high requirements.
PM891 connects to the S800 I/O system through the optical Modulebus. It can act
as a stand-alone Process Controller, or as a controller performing local control tasks
in a control network.
Two PM891 controllers can function together as a redundant pair, with one PM891
acting as the primary controller and the other acting as the backup. The backup
controller takes over the process controller tasks if any hardware error occurs in the
primary controller.
The control network connectivity is obtained by two built in IEEE802.3 Ethernet
channels on PM891.
PM891 also provides a communication expansion bus (CEX-Bus) to which a
number of expansion modules can be connected. These modules offers connectivity
to a wide range of field bus and I/O systems. In case of a redundant pair, both
PM891s are connected to the same CEX-Bus and one of them can control the
modules.
Physically, the PM891 Processor Unit consists of:
• Connector for power supply and status signals (L+, L-, SA, SB).
• DB25 connector for Electrical CEX-Bus.
• External battery connector.
• RJ45 connectors for the two Ethernet channels.
• One Com port.
• Optical Modulebus connector for connection to a maximum of seven clusters,
with 12 non-redundant or six redundant modules (that is, 7x12 = 84 modules).
• Connectors for Redundancy Link.
• SD (Secure Digital) memory connector.
• LEDs.
• Pushbutton reset switch
Processor unit redundancy is available for PM861, PM864, PM865, PM866, and
PM891. In this case, the controller contains two processor units, each including
memory for system and application software. One unit is acting as primary, the
other is backup (hot stand-by). The primary processor unit controls the process. The
backup stands by, ready to take over in case of a fault in the primary. The
changeover is done bumplessly and in less than 10 ms. During the changeover, the
process outputs are frozen.
Following a changeover, the system operates as a system without redundancy with
only one processor unit in operation. You can replace the malfunctioning processor
unit while the system is running. After the replacement is carried out, the system
once again has a redundant processor unit.
If an error arises in the backup unit, you can also replace the backup unit while the
system is running.
Errors which occur in the backup unit can never affect the primary unit's operation.
The primary unit and the backup unit are logically separated from one another.
Hardware errors in the primary processor unit cause the system to perform a correct
changeover. These hardware errors are single errors.
The application programming and the communication are totally unaffected by the
redundancy.
