Internal Detector Tests - Emerson Rosemount 975UF Reference Manual

Reference Manual
00809-0100-4977
NOTICE
The auxiliary relay is available only in models with output configurations - 1RXXXXX and
2RXXXXX.
The 0-20 mA is available only in models with output configurations - 1AXXXXX, 2AXXXXX,
and 3AXXXXX.
1.6

Internal detector tests

The detector performs two types of self-tests:
• Continuous feature test
• Built-in test (BIT)
1.6.1 Continuous feature test
The detector is supplied with default settings, containing Continuous Feature Test. To
change these settings, refer to Modbus
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:
—
—
• 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
Rosemount 975UF
Opens in output configurations 1A, 2A, and 1R
Closes in output configurations 3A and 2R
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Manager Manual.
Introduction
June 2021
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