Installation, Operation and Maintenance Manual
MAN712 Rev. 9
June 2021
Working Principle and Detailed Description
Section 5: Working Principle and Detailed Description
19
The following configurable operating modes are available (see Section 5.1.1 and
Section 5.2.2.3 for details):
•
data acquisition
•
valve control
•
valve c data acquisition
•
sleep
•
slow sampling
In
data acquisition
(ACQ.) operating mode the pressure and position (optional) samples
relevant to an event (1, 2, 3, 4, and 5) are stored in the data memory but an event does not
affect the valve position.
In
valve control
(VC) operating mode the pressure and position (optional) samples
relevant to an event (1, 2, 3, 4 and 6) are not stored in the data memory but in case of
EVENTS 2, 4 and 6 the ELBS-20 sends a command to the actuator to stroke the valve to the
fail-safe position (Safety Action).
In
valve c data acquisition
(VC+ACQ) operating mode the pressure and position
(optional) samples relevant to an event (1, 2, 3, 4, and 6) are stored in the data memory
and in case of EVENTS 2, 4 and 6 the ELBS-20 sends a command to the actuator to stroke
the valve to the fail-safe position (Safety Action).
The
sleep
(SLEEP) operating mode is used to inhibit both data acquisition and valve control
operating modes to put out of service the ELBS-20.
In
slow sampling
(SLOW) operating mode the Analog Inputs are measured; the events are
not stored and the safety action is not performed.
In case of
alarm
, the ELBS-20 automatically enters in the "slow sampling" operating mode.
In the above state the valve control and acquisition functions are off, but the ELBS-20
restores to the normal operating mode when the cause disappears.
The following figure shows the “data acquisition area” in function of the time.
Figure 9
Pressure bar
Max Pressure
Pressure drop
in valve control
Pressure drop
in acquisition
Min. pressure
Data
acquisition
area
min.
Time
