Transcript Thin Clients - The Cassandra Project

Use of Thin Clients in an
Industrial Environment
Foxboro Southeast User’s Group
Birmingham, Al
February 10-11, 2009
Walter Conner
Senior Plant Engineer
Definition
Network computer without
long term storage
devices, which typically
rely on a server for
application processing
Manufacturers include HP,
WYSE, NCD and others
Quick History
 Part of a control board modification project
 First used as a replacement for hard panel
annunciators in Solaris platform with no
operator interaction
 Linux based OS. Single head device using
telnet as communication protocol
 Used existing FoxView licenses
 Great reliability, easy to use and configure
Before
After
History (cont’d)
 Migration to MESH required change to
Windows XP for workstations, but you can
use Linux, XPe or CE as thin client OS.
 Involved Foxboro technical personnel to
evaluate use of thin client technology
 Plant decision to use thin client as a control
screen and alarm screen with the MESH
upgrade
Advantages
 Runs minimal software on the thin client
(web browser, remote desktop, etc)
Most applications reside on the server.
 Easy to secure. Device comes in a locked
down environment from the factory. Device
has some security software installed that can
be configured for your site.
 Low cost ~ $ 500 per device for Windows
XPe version, less for LINUX or Windows CE
Advantages – Cont’d
 No moving parts, so it operates in dirty
environments well
 Low power consumption ~50 watts per device
 Updates to the server updates all connecting
thin clients
Advantages – Cont’d
 After one device was configured, a custom
image was made and loaded onto the other
clients.
 After the image is restored, it takes minimal
steps to configure device and get it ready for
operation.
Disadvantages:
 Required a private network to be managed
separate from Foxboro MESH network
 Relies on a server for processing so
redundant servers were needed for mission
critical applications
 Steep learning curve about the thin client
device
Operator workstations
 Dedicated for one purpose – access to
control system displays for monitoring and
control
 Workstations were needed in more than one
place – control room, FGD absorber area,
ammonia storage area, checkout, etc.
 WPs were not used for data logging – this
task is typically performed on server
Installation
 Upgraded server system
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Use of Windows terminal services requires a
Microsoft license
Additional FoxView licenses from Foxboro
Additional memory requirements because all
processing is on the server box
RAID 5 drive system for high reliability
Installation
 Old system contained 3-AWs and 7-WPs and 8 thin
clients for alarm screens
 New system is a hybrid system of Foxboro equipment
and some thin client equipment


Some Foxboro AWs
7
 Operator stations
-4
 Engineering station - 1
 Thin client servers - 2
Some thin clients
8
 Thin client count includes 4 alarm screens and 4
operator interfaces
 Alarm screens do not have keyboard or mouse and
are not accessible by the operator
Issues
 Functionality of the thin clients required securing the
device better - this does take some time and
expertise !! I requested help from our IT people as
they had someone in house that knew what they
were and had some experience with them.
 Some custom scripts had to be written to minimize
operator interaction. i.e Distribute load between
servers, launch specific display
 UPS power for operation during trip events
 Private network requires rugged design
( don’t
use cheap devices )
Questions???