The ICS Triplex T8442C is a high-integrity TMR (Triple Modular Redundant) speed monitor module designed for the Trusted safety system. It is TÜV certified to IEC 61508 SIL 3, providing the highest level of safety for critical rotating machinery protection. The module features a unique "TMR within a TMR" architecture, where triplicated processors provide overspeed and over-acceleration trip functions completely independent of the main Trusted processors. This allows the Speed Monitor to continue protecting rotating equipment even if the Trusted processors are completely removed from the system.

Key technical specifications include 9 triplicated speed pulse inputs capable of measuring up to 30,000 Hz (0.1 Hz - 2 kHz), with an accuracy of 0.01% and 1 ms SOE resolution. The module features 6 quad-redundant relay outputs (3 overspeed and 3 over-acceleration) with de-energize-to-trip logic, and a response time of less than 20ms for high RPM applications. The T8442C is compatible with active, passive, and open collector speed probes, and includes 2500V impulse withstand opto/galvanic isolation barriers.

The module is designed for hot standby configurations using the companion slot, allowing online replacement without shutting down the system. Front panel LEDs provide status for module health, operating mode, and rotating machine group I/O status. The T8442C includes comprehensive automatic diagnostics and self-test, with hardware implemented fault tolerance (HIFT).

The T8442C interfaces with T8846 Speed Input Field Termination Assembly (SIFTA) for signal conditioning and T8891 Speed Output Field Termination Assemblies (SOFTA) for shutdown control outputs. The module can monitor up to three rotating machine groups (turbine trains) per module, with each group comprising three TMR speed input channels and two quad-redundant fault-tolerant output structures.

Common applications include steam and gas turbines, compressors, pumps, fans, and generators in power generation, oil & gas, petrochemical, and LNG facilities. The T8442C exceeds the requirements of API670 and API612 standards, making it suitable for critical turbomachinery protection.