Sensor Removal; Device Behavior On Sensor Removal - ABB AWT420 Operating Instruction

24 AW T4 2 0 | U N I V E R S A L 4 - W I R E , D U A L- I N P U T T R A N S M I T T E R | O I/A W T4 2 0 - E N R E V. B
...8 Hot plug-in (EZLink sensors only)

Sensor removal

When a sensor is disconnected, the diagnostic message
(to 2):Removed is displayed in the status bar at the bottom of
the main Operator page.
To remove a sensor permanently, press the
Ack Sensor Removed from the Operator page menu. This clears
all the output settings associated with the input (including
analog output sources and alarm sources) and disables any
associated digital output and relay sources. If one sensor
remains connected, the Operator page display for the
remaining sensor and any diagnostic messages related to the
sensor removed are cleared. If no sensors are connected, the
Operator page is blank.
To remove a sensor temporarily, DO NOT acknowledge sensor
removal as described above. Sensor setup parameter settings
for the input channel are retained.
NOTICE
To maintain the value of analog, digital and relay outputs
during temporary sensor removal, press the
Manual Hold from the Operator page menu.
If a failure current has been configured for an analog
output, the output's value is not held. Sensor removal is
classed as a failure by the diagnostic system and this
overrides the existing analog output current.
If a sensor is subsequently refitted, reconnection is detected by
the transmitter and measurement using the sensor resumes.
The diagnostic message is cleared and the state of any analog,
digital and relay outputs are restored together with their
associated alarm settings.
S1

Device behavior on sensor removal

If a sensor is assigned as the source of an analog output and
the sensor is disconnected from the transmitter, the analog
output is driven to the configured failure current. If a failure
key and select current has not been configured, the analog output is driven to
the minimum configurable output current.
If a sensor is assigned as the source of a low process alarm and
the sensor is disconnected from the transmitter, the alarm is
triggered. All digital outputs and relays assigned to the same
alarm source are also set according to their configured polarity.
and select