GE PACSystems RX7i, User Manual

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GFK-2224Q January 2017 199
Chapter 11 RX7i PLC Monitoring Via the Web
The PACSystems RX7i embedded CPU Ethernet Interface provides PLC data monitoring using a standard Web
browser. Rack-based Ethernet modules and the RX3i embedded Ethernet interface do not support web server
operation.
You can use the Web server to monitor the following PLC data:
▪
PLC reference tables. This data is a snapshot of the PLC Reference Tables when the data is displayed in
the Browser and is not updated until you request another display. All reference tables are supported.
▪
PLC and I/O Fault Tables.
The web server cannot be used to modify PLC data (acknowledge alarms, set/force values in tables).
The maximum number of web server connections that can be configured for the Ethernet Interface is 16. If the
system includes FTP server connections, fewer web server connections are available, as explained in 0.
11.1
System Requirements
Web monitoring requires version 4.0 or later of Netscape Navigator or Internet Explorer. The browser must be
capable of running the Java Virtual Machine (JVM) version 1.3 plug-in. The supported host operating systems
are Windows NT 4.0 SP5 or SP6, Windows 95B, Windows 98 (First Edition Service Pack 1, Second Edition), and
Windows 2000 Professional SP1, Windows Millennium Edition, Windows XP and Windows CE 3.0. To view the
entire Reference Table page, the screen resolution must be 1024 x 768 or higher. Local web firewall blocking
issues will be avoided by using HTTP protocol on port 80 to transfer standard HTML files including JavaScript
and Java applets from the server to the browser and HTTP Post command to transfer form information from
the browser to the server.
11.2 Disabling Pop-up Blocking
Most internet browsers provided a feature that blocks pop-up windows. This prevents the viewing reference
tables. Change your browser settings to permit pop-ups.
11.3
Web Server Operation in a Redundant System
In a redundant system, only the active unit processes Web Server requests at the Redundant IP address and
responds to web page requests. The backup unit does not respond to the Redundant IP address. When the
active Ethernet interface changes to backup, it takes down all Web Server connections and their underlying
TCP connections. The Web Server maintains its underlying TCP connection only long enough to process each
web page request; a new TCP connection is opened, used, and closed for each subsequent web page display or
update. Unless a web page change or update is requested during a redundancy switch, the operation of the
Redundant IP address is transparent to the Web browser. Any web page request in process over the
Redundant IP when a role switch occurs is ended.
Although both the active and backup units respond to Web server requests received at the direct IP address,
having a remote (host) browser issue Web Server requests to the direct IP address is not recommended.
Remote web browsers should use the Redundant IP address when communicating to a Redundant System.
11.4
Standard Web Pages
The CPU Ethernet Interface is shipped with a set of standard PLC web pages already installed. These standard
web pages include a PLC home page, a Reference Table display page, a PLC Fault Table display page, and an
I/O Fault Table display page. When necessary, new or revised web page files may be transferred into the
Ethernet Interface via the standard FTP protocol, as described later.