Redundancy Master

Kepware의 RedundancyMaster는 다중 OPC 서버들이 리던던트 페어들로 설정되게 하여 OPC 데이터의 신뢰성과 가용성을 증가시킵니다. 그리하여 완벽하게 모든 OPC 클라이언트 응용 프로그램에 하나의 OPC 서버로 표시됩니다.

Resources



Product Description


RedundancyMaster Features:

Explore the features that will change how you think of OPC redundancy. The innovations in RedundancyMaster can work together seamlessly with your current OPC application to give you a more reliable solution.

Primary/Secondary Machine Names

Browse for the primary machine which specifies the preferred connection that should be made to an OPC server and the secondary machine which specifies the fallback connection that should be made to an OPC server when communications to the primary machine are unavailable. Every time a new client connection is made to the underlying server, the application will first attempt to make a connection to the server running on the primary machine. In the event that the connection to the primary fails or communications to the primary is lost, a connection to the secondary server will be attempted and, if available, established. Depending on the connection mode, you can configure the application to automatically establish communications with the primary machine when it becomes available.

Connection Mode

The connection mode defines how and when the redundancy application should connect to the underlying primary and secondary servers. The mode in which you operate affects the amount of time it takes to fail over from one OPC server to the other. Some modes allow you to automatically promote communications to the primary when it is available. The following summarizes connection modes:

Cold (Active machine only):

In this mode, the application will only connect to one underlying server at a time. On startup, a connection to the primary server will be made and all client related requests will be forwarded onto the primary. In the event that the connection to the primary fails, or communications to the primary is lost, a connection to the secondary will be made. If the redundancy application is unable to obtain a connection to the secondary, it will continue to ping-pong between the two servers until it makes a successful connection.
The 'cold' connection mode minimizes the amount of system resources that are allocated since there will only be one connection to one server at any given time. It also reduces network traffic since there is no need to poll the inactive machine in addition to the active machine, as in other modes. The drawback to this setting is the amount of time it takes to fail-over to the inactive server. When communications loss is detected with the active server, the application needs to establish the connection to the inactive server, subscribe to all items on behalf of the client and initiate the appropriate callback mechanisms.

Warm (Both machines, subscribe to items on active machine):

In this mode, the application will attempt to maintain a connection to both the primary and secondary servers at all times. Only items in the primary server will be active and polled. In the event that the connection to the primary fails, or communications to the primary is lost, the identical items in the primary server will be set to active in secondary server. Periodically, both servers will be pinged to determine if the connection is still valid.
The 'warm' connection increases the amount of system resources that are allocated, since there will be two server connections made on behalf of the client. There is also a minimal increase in network traffic due to periodically pinging two servers instead of one, as in 'Cold' mode operation. The benefits are that fail-over time is minimized over 'Cold' mode operation, since the redundancy application will only have to initialize data callbacks to the inactive server to begin receiving data. If you need to minimize the loss of data in your application, and at the same time want to minimize network traffic, you should use this connection mode.

Hot (Both machines, subscribe to items on both machines):

In this mode, the application will attempt to maintain a connection to both the primary and secondary servers at all times. On startup, the application will initialize data callbacks for both primary and secondary servers so that both servers will send data change notifications. The data received from the primary server will be forwarded onto the client. In the event that the connection to the primary fails, or communications to the primary is lost, data received for the secondary will immediately be forwarded onto the client. In either case, writes will only be forwarded to the active server. Periodically, both servers will be pinged to determine if the connections are still valid. If at anytime the redundancy application loses communications to either server, it will periodically attempt to reconnect to the failed server. This setting increases the amount of system resources that are allocated, since there will be two server connections made on behalf of the client. There is also an increase in network traffic due to receiving data change notifications from both underlying servers, as well as periodically pinging both servers to determine if they are still available. The benefit of this setting is that fail-over time occurs immediately after detecting the loss of the active server. If loss of data is very crucial to your application, you should use this connection mode.

OPC Server Aliasing: This feature will allow you to configure multiple pairs of OPC Servers with the same ProgID (KEPware.KEPServerEX.V5). This feature permits you to use one OPC Server vendor if you have multiple OPC Server nodes on your network. This will allow OPC clients to connect to a specific redundant pair by referring to the aliased ProgID of that redundant pair.

Always connect to primary machine upon availability

This setting enables RedundancyMaster to automatically promote communications back to the primary machine when the OPC server becomes available.

Query Server Status Interval

This interval (specified in milliseconds) determines how often RedundancyMaster will ping the underlying servers to determine if there has been a loss of communications. By querying at a faster rate, you can minimize fail-over time since failure detection occurs more frequently.

Query Server Status Timeout

This interval (specified in milliseconds) determines how long the redundancy application will wait for a ping response from the underlying servers before considering there to be a loss of communications.

Monitoring Settings:

This feature allows you to configure certain conditions which will initiate a fail-over to the inactive server. These conditions allow you to monitor server items for specific states to determine the health of the underlying servers/devices, above and beyond the automatic fail-over that will occur due to the loss of communications.

Diagnostics Settings:

Preserve events to disk on shutdown: Events will be preserved to disk when the application is shutdown. The next time the application is started, the events will be displayed and any new events will be concatenated to the end of the view.Maximum number of events to capture: Since diagnostics utilizes memory and storage resources, you may want to limit the number of diagnostics that are preserved at any given time. Once the maximum number of events has been reached, the oldest events will be discarded as necessary.

Notifications Settings:

This feature allows you to configure one or more recipients to receive email notifications for one or more diagnostics events. The events that are available to send as email notifications are the same events visible to the local Diagnostics Settings event view.

RedundacyMaster Diagrams:

Broadcasting Proprietary Ethernet IP Data

Broadcasting Proprietary Ethernet IP Data

This diagram above shows how the proprietary Ethernet IP data is manipulated within the plug-in device driver of KEPServerEX to become OPC Data, which is then served out to the OPC Client in a basic redundant system.
Local Machine Redundancy

Local Machine Redundancy

This scenario has the OPC Client, RedundancyMaster, and the Secondary OPC Server residing on the Local Machine with the Primary OPC Server on a Remote Machine. In this scenario be sure to make the most reliable Server your Secondary OPC Server. This scenario also reduces the need for another machine to run the Secondary OPC Server.
Single OPC Server Pair Redundancy

Single OPC Server Pair Redundancy

This is a standard use diagram for one Server Pair where RedundancyMaster resides on the same machine as the OPC Client, and the two OPC Servers are on remote machines.
Multiple OPC Server Pair Redundancy

Multiple OPC Server Pair Redundancy

RedundancyMaster can be configured to have multiple OPC Server Pairs. In this diagram there are two pairs of OPC Servers which are gathering data from two separate device networks. If the multiple OPC Server Pairs are all of the same ProgID (KEPware.KEPServerEX.V4), then you will need to use the Aliasing feature; if the two pairs have different OPC Servers with different ProgIDs then you will not need the Aliasing feature.

RedundancyMaster Client Interfaces

Application Connectivity Support : OPC Data Access: 1.0a, 2.0, 2.05a

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OPC Kepware 담당자 :
  • 전 화 :  02-538-3311
  • E-mail  :  chyoo@samboo.co.kr




OPC Kepware 제품 설명은 전화와 E-mail을 주십시요.



자세하게 설명해 드리겠습니다.

OPC Kepware 담당자 :
  • 전 화 :  02-538-3311
  • E-mail  :  chyoo@samboo.co.kr