19
1.6
Internal Detector Tests
The detector performs two types of self tests:
•
Continuous Feature Test, page 19
•
Built-In-Test (BIT), page 19
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
•
0-20mA level output
•
Relays and heater operation
•
Processor Watch dog
•
Software
•
Memory
•
Oscillator frequency
Response to Fault Indication
If a failure is found, the detector indicates by:
•
Fault relay:
•
Opens in wiring option 1, 2, and 4
•
Closes in wiring option 3 and 5
•
0-20mA: indic ates Fault (0mA or 2mA) in wiring option 1, 2, 3
•
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 BIT in the following modes:
•
Automatically and manually
•
Manually only
Note:
In Manual BIT, the outputs may also be tested and Control System ‘inhibit’ should
be applied if this could initiate other systems.
Содержание SharpEye NP40IGB
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