Moore Industries' STA Safety Trip Alarm for IEC 61508 safety applications is now featured as a logic solver in exida's exSILentia integrated safety lifecycle software. Exida says its exSILentia software is taking the lead among safety lifecycle engineering tools.
The STA device is part of Moore's FS Functional Safety Series, and performs as a logic solver, capable of acting on potentially hazardous process conditions. Moore says it warns of unwanted process conditions and provides emergency shutdown or on/off control in safety instrumented systems (SIS) and traditional alarm trip applications.
By including the STA in the exSILentia software tool, exida has provided competent functional safety practitioners a way to determine the STA's applicability in specific safety-related applications. Before including the STA, functional safety experts at exida had to review and approve all failure modes, effects, and diagnostic analysis (FMEDA) data.
In the exSILentia tool, safety practitioners can select the 4-wire (line/mains-powered) STA as an economical logic solver that accepts current and voltage signal input from transmitters, temperature sensors, resistance, potentiometer devices, and more.
The STA can be configured for a wide variety of safety instrumented functions (SIFs) for safety related applications. The high-availability alarm trip is designed for safety instrumented systems up to SIL 2 and the firmware is suitable for use in a SIL 3 system, in a 1oo2 (one-out-of-two) voting architecture.
The STA provides three failsafe alarm outputs. Two are configurable process alarms that trip when a monitored process variable falls outside of user-set high and/or low limits. The third alarm is a non-programmable, latching alarm that is activated if any internal faults are found by the STA's internal diagnostics. This fault relay is also triggered if the input is faulty or broken.
Moore says the STA offers features critical to safety applications:
• 20-bit input resolution;
• Long term stability of up to five years between scheduled calibrations;
• Rugged, industrial metal housing;
• Isolation and RFI/EMI protection that provides protection against the effects of ground loops, plant noise, and interference; and
• Standard transmitter excitation that provides 24V power to a 2-wire transmitter.
-Edited by Peter Welander, process industries editor, firstname.lastname@example.org
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