Use of Thin Clients in an Industrial Environment

Foxboro Southeast User’s GroupBirmingham, Al

February 10-11, 2009

Walter ConnerSenior 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 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???