Category: ICS TRIPLEX

Description 

The Trusted 40 Channel Analogue Output or Digital Output FTA T8850 provides termination 

for a maximum of 40 output field loops. The 40 channels are arranged in five groups each 

comprising eight identical channels.  

Indication of the presence of the field power supply is provided by a green LED (one for each 

power group). 

The signal to the field device is routed through the FTA from the output module. 

The cable linking the 40 channels on the output module to the FTA is terminated at the 96

way socket JDH2. SmartSlot (Version 1) signals from the module are also connected to JDH1. 

The dc field power supplies can be connected to the FTA via a 10-way terminal block P1. The 

output signals to the field (40-off) are connected by 2-wire arrangements terminated on the 

dual height terminal blocks TB2.

Installation 

Trusted 40 Channel Analogue Output or Digital Output FTA T8850 is designed to be 

mounted on either of the TS32 or TS35 DIN rails in the horizontal or vertical positions as 

required.

Trusted 40 Channel Analogue or Digital Output FTA 

Product Overview 

The Trusted® 40 Channel Analogue Output or Digital Output Field Termination Assembly (FTA) is 

designed to act as the main interface between the Trusted Triple Modular Redundant (TMR) 24 Vdc 

Digital Output Module T8451, Trusted Triple Modular Redundant (TMR) 24/48 Vdc Digital Output 

Module T84611 or Trusted TMR Analogue Output Module T8480 and the field device. 

Features: 

• 40 output channels per FTA. 

• Industry standard field device connections (2-wire). 

• Standard DIN rail compatibility. 

• Screw clamp terminals on both field and power. 

• Simple installation and connection. 

• 24 Vdc operation. 

• SmartSlot connection for ‘one to many’ hot replacement of output modules. 

• Five isolated groups of eight channels. 

• On-board LED indication of field power supply. 

• Field terminal wire size allowance 12 AWG to 28 AWG. 

Trusted TMR Expander Interface Adapter Unit 

Product Overview 

This document provides general information for the Trusted® Triple Modular Redundant (TMR) 

Expander Interface Adapter Unit T8312. Two versions of the Unit are available; one providing 

inter-connection between the Trusted Expander Interface Modules in the Controller Chassis and 

four Expander Chassis (T8312-4), and the other providing inter-connection to seven Expander 

Chassis (T8312-7). 

Features: 

• Allows easy inter-connection of Controller and Expander Chassis. 

• Unit is fully shielded for Electro-Magnetic Compatibility (EMC). 

• Version available for smaller Trusted Systems – up to four Expander Chassis. 

• Locking connectors for increased reliability.

Description 

The Trusted Expander Interface Adapter Unit T8312 comprises four, or seven 12-pin ODU 

connectors (dependent on type of Unit), a printed circuit board (PCB), a 96-way C type 

connector which plugs into a double 96-way connector assembly designed to be connected 

to the Trusted Expander Interface Modules resident in the Controller Chassis. The Unit is 

contained within a metal enclosure and is designed to be clipped onto the Controller Chassis 

rear connectors. A release button is provided to enable the Unit to be disconnected. 

The TMR 24V dc analog input module, shown in Figure 6-10, interfaces to 

40 sourcing field input devices. The module acts as a current sink for the 

devices.  

The module can detect open and shorted field cables using the built-in line

monitoring feature. Line monitoring functions are independently configured 

for each input channel. 

The module provides on-board sequence of events (SOE) reporting with a 

resolution of 1ms. A change of state triggers an SOE entry. States are 

determined by voltage thresholds that can be configured on a per channel 

basis.  

The input status LED mode is dependent upon the voltage level of the field 

I/O signal. Each field input voltage is measured and compared to six 

threshold levels (four configurable and two fixed) which produce seven 

threshold bands, as described in Section 8. Each threshold band can be 

defined to have a particular indicator mode: off, solid or flashing green, or 

solid or flashing red.

Host Interface Unit (HIU)

The HIU is the point of access to the Inter Module Bus (IMB) for the Module.

It also provides power distribution and local programmable processing

power. The HIU is the only section of the I/O Module to directly connect to the

IMB Backplane. The HIU is common to most Trusted I/O types and has type

dependent and product range common functions. Each HIU contains three

independent slices, commonly referred to as A, B, and C.

All interconnections between the three slices incorporate isolation to prevent

any fault interaction between the slices. Each slice is considered a Fault

Containment Region (FCR), as a fault on one slice has no effect on the

operation of the other slices.

The HIU provides the following services common to the modules in the

family:

• High Speed Fault Tolerant Communications with the TMR Processor

via the IMB interface.

• FCR Interconnect Bus between slices to vote incoming IMB data and

distribute outgoing I/O Module data to the IMB.

• Optically isolated serial data interface to the FIU slices.

• Redundant power sharing of dual 24 Vdc chassis supply voltage and

power regulation for logic power to HIU circuitry.

• Magnetically isolated power to the FIU slices.

• Serial data interface to the FPU for Module status LEDs.

• SmartSlot link between active and standby modules for coordination

during Module replacement.

• Digital Signal Processing to perform local data reduction and self

diagnostics.

• Local memory resources for storing Module operation, configuration,

and field I/O data.

• Onboard housekeeping, which monitors reference voltages, current

consumption and board temperature.

Field Interface Unit (FIU)

The Field Interface Unit (FIU) is the section of the Module that contains the

specific circuits necessary to interface to the particular types of field I/O

signals. Each Module has three FIUs, one per slice. For the TMR 24 Vdc Digital

Input Module, the FIU contains an individual analog to digital (A/D) converter

for each of the 40 field inputs.

The FIU receives isolated power from the HIU for logic. The FIU provides

additional power conditioning for the operational voltages required by the

FIU circuitry. An isolated 6.25 Mbit/s serial link connects each FIU to one of

the HIU slices.

The FIU also measures a range of onboard “housekeeping” signals that assist

in monitoring the performance and operating conditions of the Module.

These signals include power supply voltages, current consumption, onboard

reference voltages and board temperature.

Features

• 40 Triple Modular Redundant (TMR) input channels per module.

• Comprehensive, automatic diagnostics and self-test.

• Selectable line monitoring per channel to detect open circuit and short

circuit field wiring faults.

• 2500 V impulse withstand opto/galvanic isolation barrier.

• Onboard Sequence of Events (SOE) reporting with 1 ms resolution.

• Module can be hot-replaced online using dedicated Companion

(adjacent) Slot or SmartSlot (one spare slot for many modules)

configurations.

• Front panel input status LEDs for each channel indicate input status

and field wiring faults.

• Front panel module status LEDs indicate module health and

operational mode (Active, Standby, Educated).

• TϋV Certified IEC 61508 SIL 3.

The Trusted® TMR 24 Vdc Digital Input Module is a member of the Trusted

range of Input/Output (I/O) modules. All Trusted I/O Modules share common

functionality and form. At the most general level, all I/O Modules interface to

the Inter-Module Bus (IMB) which provides power and allows communication

with the Trusted TMR Processor. In addition, all Modules have a field interface

that is used to connect to module specific signals in the field. All Modules are

Triple Modular Redundant (TMR).

Product overview

The Trusted® TMR 24 Vdc Digital Input module interfaces to 40 field input

devices. Fault tolerance is achieved through a Triple Modular Redundant

(TMR) architecture within the module for each of the 40 input channels.

Each field input is triplicated and the input voltage is measured using a

sigma-delta input circuit. The resulting field voltage measurement is

compared to user configurable threshold voltages to determine the reported

field input state. When a line-monitoring device is installed at the field switch,

the module can detect open and short circuit field cables. Line monitoring

functions are independently configured for each input channel. The

triplicated voltage measurement, coupled with onboard diagnostic testing,

provides comprehensive fault detection and tolerance.

The module provides onboard Sequence of Events (SOE) reporting with a

resolution of 1 ms. A change of state triggers an SOE entry. States are

determined by voltage thresholds that can be configured on a per channel

basis.

Overview 

The TMR Expander Processor is a fault tolerant design based on TMR architecture arranged 

in a lock-step configuration. Figure 1 shows, in simplified terms, the basic structure of the 

TMR Expander Processor. 

The Module has three main fault containment regions (FCR A, B and C). Each of the main 

FCRs contains interfaces to the Expander Bus and Inter-Module Bus (IMB), an active/standby 

interface to the other TMR Expander Processor in the Chassis, control logic, communications 

transceivers and power supplies. 

Communication between the Module and the TMR Processor is via the TMR Expander 

Interface Module and the triplicated Expander Bus. The Expander Bus is triplicated, point-to

point architecture. Each channel of the Expander Bus comprises separate command and 

response media. Voting is provided at the Expander Bus Interface to ensure that cable faults 

are tolerated, and the remainder of the Expander Processor operates in a fully triplicated 

mode, even in case of cable faults occurring. 

Communication between the Module and the I/O Modules in the Expander Chassis is via the 

IMB on the Backplane of the Expander Chassis. The IMB is identical to that within the 

Controller Chassis, providing the same fault tolerant, high bandwidth communications 

between the Interface Modules and the TMR Processor. As with the Expander Bus Interface 

all transactions are voted, localising faults to the IMB should they occur. 

A fourth FCR (FCR D) provides the non-critical monitoring and display functions and is also 

part of the inter-FCR Byzantine voting structure. 

Isolation is provided between FCRs wherever interfaces are required, to ensure that faults 

cannot propagate between them.