- December 17, 2020
- Moore Industries-International, Inc.
Part of the Moore Industries FS FUNCTIONAL SAFETY SERIES, the exida® certified SIL 2 and SIL 3 capable STA Safety Trip Alarm performs as a logic solver and acts on potentially hazardous process conditions; warns of unwanted process conditions; provides emergency shutdown; or provides on/off control in Safety Instrumented Systems (SIS) and traditional alarm trip applications. The STA safety trip alarm has a systematic integrity up to SIL 3 and random integrity up to SIL 2 which allows the STA to be used in a redundant architecture (1oo2, 2oo3, etc.) up to SIL 3.
The 4-wire (line/mains-powered) STA accepts a signal input from transmitters (current and voltage inputs), temperature sensors (RTD and thermocouple inputs), resistance and potentiometer devices, and a wide range of other monitoring and control equipment.
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 extensive internal diagnostics. This fault relay is also triggered if the input is faulty or broken.
The STA features:
- Industry-best 20-bit input resolution.
- Long term stability of up to 5 years between scheduled calibrations.
- A rugged, industrial metal housing.
- Isolation and RFI/EMI protection that provides superior protection against the effects of ground loops, plant noise, and radio frequency and electromagnetic interference.
- Standard transmitter excitation (-TX) that provides 24V power to a 2-wire transmitter.
- Optional analog output (-AO) to provide a combination alarm trip and transmitter in one compact unit.
In addition, the STA has had an in-depth EMPHASIS assessment by EDF Energy. Assessment by the EMPHASIS methodology ensures “Production Excellence” of the device by examining a series of criteria including the company, its core competencies, the tools and techniques used in the design and production of the product and the testing requirements. This additional rigorous examination, based on the IEC 61508 standard resulted in the STA safety trip alarm achieving a SIL 2 capability for use in the UK nuclear industries.