ABB Safety Triguard 2 TMR Safety Products

 and watchdog timer circuits are managed so that circuits will default to

 a predetermined safe state.

Highest Speed of Response

By using advanced processor technology, whilst maintaining the stability of the original 

core software, Triguard SC300E delivers an unrivalled scan time resolution of 10ms.

Product Hardware and Software Description

The ABB Triguard SC300E TMR product has a fully triplicated system architecture from input module to output module. Each system comprises one or more identical chassis housing the power supplies, processors, I/O and communications modules as required by the application.

Each processor correlates and corrects its memory image of the current state of the system using a software vote, logging any discrepancies in the diagnostic table. Each processor then executes its programmed application logic and sets its respective outputs to the required state.

of the customer application. Extension chassis are always complete with two power supply units and three bus extender modules.

• A Remote Master Chassis

Always equipped with two power supply units and three fibre optic

A single system may be as small as one chassis or as large as 15, giving a maximum of 9,500

 I/O. The system is designed to achieve the highest possible reliability, 

safety and availability and still provide economic advantage. System availa

bilities in excess of 99.999% can readily be realised, maximising the potent

ial uptime for a customers process plant. All SC300E inp

ut and output modules interface to three isolated I/O communication buses, each being controlled by one of the three processor modules. Field input signals are filtered and split, via isolating circuits on the inpu

t modules, into three identical signal processing p

aths. Each path is controlled by a micro-controller to coordinate processing, testing and status reporting to the respective processor. Each processor communicates with its two neighbours via isolated, read only, 

high speed links to synchronise input, output and diagnostic status information at least once every scan. Commanded output status from the processors are received by an output module wh

ich, using a 2oo3 hardware voter, sets the outputs to the field

. Any discrepancy is detected by the micro-control

lers and reported to the processors. All input and output modules can

 be optionally configured with a hot spare partner module. Thi

s allows repairs to be carried out without affecting the operation of the system.

Triguard SC300E Chassis System

There are four basic types of chassis, all using the same mechanics,

 each providing 10 slot positions for I/O modu

les and redundant power supplies.

• The Main Chassis

One per system is required and is always complete with two po

wer supply units, three processor module

s, the chassis backplane with triple bus systems and plug/socket syste

m module connectors.

• An Extension Chassis

Up to 14 chassis can be connected to a main chassis to suit the capac

ity master bus extender modules. The master chassis can service 

up to four remote chassis.

• A Remote Chassis

Always equipped with two power supply units and three fi

bre optic slave bus extender modules. A remote chassis ca

n be sited up to 2km away from a remote maste

Processor

Each Triguard SC300E TMR system contains three processors. Each processor operates asynchronously in parallel with the other two processor modules and receives power from the redundant power supply units in the main chassis. A triplicated bus system on the chassis backplane connects Key features of the processor modules:

• Intel processor 

• Battery backed static RAM for application logic 

• RAM Battery backup supply for six months 

• 1 Mbyte of EPROM 

• Real time clock for data logging to 10ms resolution

each of the three processors to the I/O and communications modules. The Triguard SC300E has an operating system known as the Real Time Task Supervisor (RTTS), which is installed in each of the three processors. The operating system has been proven by well over 10 million operational hours. RTTS is transparent to the user, it controls the off-line/start-up and on-line continuous diagnostic and voting functions, and provides a single environment for the application programming. On power up, comprehensive diagnostic routines check and validate the correct operating parameters of each processor. The Triguard SC300E operating system, RTTS, will permit the processors to operate in a 3–2–1 format allowing a system to continue to function with one healthy processor. A replaced processor will automatically acquire the data it requires to become operational from the on-line processor before going

Input/Output Modules

All I/O module types share an element of common design, providing component rationalisation and implementing distributed processing. The three isolated TMR signal paths of all input/output modules are supervised by a micro-controllers which: