Emerson Rosemount 975MR, Справочное руководство

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• Built-in test (BIT)
1.6.1 Continuous feature test
During normal operation, the detector tests itself continuously and indicates a fault if a
failure is found. This type of test complies with SIL-2 requirements.
The detector continuously tests:
• Input voltage level
• All internal regulator voltage level
• Voltage level status of sensor and sensor circuitry for noise or disconnection in the
electronic circuitry
• 0-20 mA level output
• Relays and heater operation
• Processor watch dog
• Software
• Memory
• Oscillator frequency
Response to a fault indication
If a failure is found, the detector indicates it by:
• Fault relay:
— Opens in output configurations 1A, 2A, and 1R
— Closes in output configurations 3A and 2R
• 0-20 mA: indicates fault (0 mA or 2 mA) in output configurations 1A, 2A, and 3A
• LED - yellow flashes (4 Hz)
• Correcting the fault
The fault indications remain until the detector's power is removed. The fault indications
return if the fault is still found when power is restored.
1.6.2 Built-in test (BIT)
The detector's built-in test (BIT) also checks the following:
• Electronics circuitry
• Sensors
• Window cleanliness
The detector can be set to perform the built-in test in the following modes:
• Automatically and manually
• Manually only
Introduction Reference Manual
August 2019 00809-0100-4975
22 Emerson.com/Rosemount