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Product Overview

The Trusted® TMR 24 Vdc Digital Output Module interfaces to 40 field devices. Triplicated diagnostic tests are performed throughout the Module including measurements for current, and voltage on each portion of the voted output channel. Tests are also performed for stuck on and stuck off failures. Fault tolerance is achieved through a Triple Modular Redundant (TMR) architecture within the Module for each of the 40 output channels. Automatic line monitoring of the field device is provided. This feature enables the Module to detect both open and short circuit failures in field wiring and load devices. The Module provides on-board Sequence of Events (SOE) reporting with a resolution of 1 ms. An output change of state triggers an SOE entry. Output states are automatically determined by voltage and current measurements on-board the Module. This Module is not approved for direct connection to hazardous areas and should be used in conjunction with Intrinsic Safety Barrier devices

Features

• 40 Triple Modular Redundant (TMR) output points per Module. • Comprehensive, automatic diagnostics and self-test. • Automatic line monitoring per point to detect open circuit and short circuit field wiring and load faults. • 2500 V impulse withstand opto/galvanic isolation barrier. • Automatic over-current protection (per channel), no external fuses required. • On-board Sequence of Events (SOE) reporting with 1 ms resolution. • Module can be hot-replaced on-line using dedicated Companion (adjacent) Slot or SmartSlot (one spare slot for many Modules) configurations.

Front Panel output status Light Emitting Diodes (LEDs) for each point indicate output 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. • Outputs are powered in isolated groups of eight. Each such group is a Power Group (PG).

The TMR 24 Vdc Digital Output 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 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).

1.1.Field Termination Unit (FTU)

The Field Termination Unit (FTU) is the section of the I/O Module that connects all three FIUs to a single field interface. The FTU provides the Group Fail Safe Switches and passive components necessary for signal conditioning, over-voltage protection, and EMI/RFI filtering. When installed in a Trusted Controller or Expander Chassis, the FTU field connector interconnects to the Field I/O Cable Assembly attached at the rear of the Chassis. The SmartSlot link is passed from the HIU to the field connections via the FTU. These signals go directly to the field connector and maintain isolation from the I/O signals on the FTU. The SmartSlot link is the intelligent connection between Active and Standby Modules for coordination during Module replacement.

1.2.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 Output Module, the FIU contains one stage of the output switch structure, and sigma-delta (ΣΔ) output circuit for each of the 40 field outputs. Two additional ΣΔ circuits provide optional monitoring of the external field I/O supply voltage.

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/sec serial link connects each FIU to one of the HIU slices. The FIU also measures a range of on-board “housekeeping” signals that assist in monitoring the performance and operating conditions of the Module. These signals include power supply voltages, current consumption, on-board reference voltages and board temperature.

1.3. 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 high integrity 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 help 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. • Galvanically 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 co-ordination 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. • On-board housekeeping, which monitors reference voltages, current consumption and board temperature.