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FactoryTalk View SE in the Cloud
Summary
FactoryTalk View SE in the Cloud
Question
Is it possible to host a FactoryTalk View Site Edition (SE) system in the Cloud?
Answer
In this context, In the Cloud generally means hosting some or all of the system off premises. The system components capable of being hosted off premises can fall into three main categories:
- Application servers (e.g., FactoryTalk View SE HMI server, FactoryTalk ViewPoint server, Data server, Alarm server)
- Application clients (Remote Desktop Services server, FactoryTalk ThinManager server)
- Historical data storage servers (e.g., Microsoft SQL server, FactoryTalk Historian SE server)
This document will assess the feasibility and recommended path for each of these three categories in the context of a FactoryTalk View SE system, beginning with a brief explanation of FactoryTalk Services requirements.
FactoryTalk Services Communication Requirements
The underlying services that connect components of a FactoryTalk System are generally referred to as the FactoryTalk Services Platform (FTSP), or FactoryTalk Services.
FactoryTalk Services provide services such as FactoryTalk name resolution, security, eventing, Live Data, and more.
A robust, reliable network connection is recommended for any communications between a FactoryTalk client (for example, a FactoryTalk View SE Client) and a FactoryTalk server (for example, a FactoryTalk View SE HMI server).
In general, slow (<100 mbps) and/or unreliable network communications (high latency, unscheduled dropouts) are not recommended.
For a more detailed explanation, refer to QA28444 – FactoryTalk Systems with Disruptive/Unreliable Networks.
Additionally, the majority of FactoryTalk Services communications rely on DCOM, which dynamically binds ports at runtime.
This makes FactoryTalk client to FactoryTalk server communications through a firewall challenging and over a NAT connection impossible.
For a more detailed explanation, refer to Microsoft Technet Articles https://technet.microsoft.com/en-us/library/cc161377.aspx and https://support.microsoft.com/en-us/help/248809/prb-dcom-does-not-work-over-network-address-translation-based-firewall.
Hosting Application Servers Off-Premises
It is technically possible to locate application servers off-premises in a FactoryTalk View SE system, but there are several challenges involved that generally make it not recommended by Rockwell Automation.
When considering an off-premises application server, the network performance and reliability to The Cloud will be the largest challenge. Poor network performance will lead to stale or bad data values from a data server communicating to an on-premises controller. Operator station performance could similarly suffer for on-premises stations, and a network disconnect could result in unplanned downtime.
A common request is to create a redundant pair of servers, with a primary set of servers off-premises and a backup set on-premises in the event of a network outage.
This presents the same challenges as a completely off-premises server solution when on-premises clients are connecting to the primary, off-premises servers, and it poses the additional challenge of the FactoryTalk Services synchronizing the server pairs.
To reduce FactoryTalk Services communication challenges, any off-premises application servers should be coupled with off-premises application client servers (for example, Remote Desktop Services servers with FactoryTalk application clients installed), with on-premises operator stations using thin client technology for access (refer to Hosting Application Clients Off-Premises for more information).
Hosting Application Clients Off-Premises
Off-premises application clients refers to the concept of remotely accessing the application clients using technology like Microsoft Remote Desktop Services. There is little to no advantage to locating application clients off-premises in a solution with on-premises application servers.
Due to the FactoryTalk Services communication requirements, it is best to keep all FactoryTalk components on the same network segment. If the system’s application servers are located off-premises, the application clients would benefit from being located in the same off-premises network. This mitigates the challenges of FactoryTalk Services communications. Off-premises application clients would be installed on a Microsoft Remote Desktop Services server, with the on-premises operator stations remotely accessing them. This provides several advantages, including automatic reconnect attempts and a small number of port requirements for any firewalls.
Note: These advantages also apply to on-premises client communications.
Hosting Historical Data Servers Off-Premises
In this context, historical data storage refers to datalog or alarm history stored, for example, in a Microsoft SQL Express database. A common historical client example is a FactoryTalk View SE client displaying a trend with historical data. Data storage and any historical clients should be considered separately; data storage requirements might be different from the ability for clients to access the data once stored.
Microsoft SQL server storage requires no FactoryTalk Services communications, meaning that the network performance and reliability challenges are different from the previous topics.
Data should be stored on-premises to prevent data loss in the event of a network disconnect to any off-premises long term storage.
On-premises historical client performance requirements should also be considered, understanding the risk in poor network performance or a network disconnect should the clients be connecting to off-premises storage.
Off-premises storage should be best considered as a long term storage solution, with an on-premises short term storage server in use for immediate collection and client requirements.
Summary
Hosting application components off-premises, while technically feasible, presents a large amount of risk and is generally not recommended. Hosting historical data storage off-premises presents fewer risks, but the general recommendation is to retain collection and client services on-premises, which would forward long term data to the off-premises storage.
Source: Rockwell Automation’s Technote database.
