June 2021
Installation, Operation and Maintenance Manual
MAN712 Rev. 9
Section 5: Working Principle and Detailed Description
Working Principle and Detailed Description
32
5.2.6
Analog Input - Pressure Transducer
The ELBS-20 is provided with a configurable (0 - 20 mA or 4 - 20 mA) analog input (AI1)
dedicated to the Pressure Transducers.
The ELBS-20 supplies a 14.5 V DC voltage to the Pressure Transducer.
The ELBS-20 can work with 2 or 3 wires Pressure Sensors.
The pressure transducer is usually supplied with the ELBS-20 and is installed on the line
valve at valve-maker/customer care, according to Biffi instructions.
The pressure transmitter must be installed downstream the line valve and converts the
pipeline pressure to a 0 - 20 mA or 4 - 20 mA electrical signal.
5.2.7
Analog Input - Position Sensor
The ELBS-20 is provided with a configurable (0 - 20 mA or 4 - 20 mA) analog input (AI2)
dedicated to the Position Sensor.
The ELBS-20 supplies a 14.5 V DC voltage to the Position Sensor.
The ELBS-20 can work with 2 or 3 wires Position Sensor.
The Position Sensor is an optional input.
5.2.8
SOV Control Outputs
The SOV Control Outputs are used for managing one or more external SOVs in order
to send a command to the actuator to stroke the line valve to the fail-safe position
(Safety Action).
The SOV Control Outputs can be used also to drive a contactor of an electrical actuator
(no SOVs required) to stroke the line valve to the fail-safe position.
See Section 5.1.2.7 for details about the Safety Action.
The ELBS-20 is provided with the following outputs dedicated to the safety action:
•
2x 24 V DC - 100 mA isolated outputs (SVC1 and SVC2).
•
2x SPDT single side stable relays contacts (RL1 and RL2).
The SOV Control Outputs can be used separately or simultaneously (see Section 6).
The following restrictions on the Configuration of the SOV Control Outputs, dealing with
the declared Power Supply sources, must be respected otherwise a configuration alarm
(CONF) is generated (see 6 for details about configuration parameters):
•
External Power Supply (“V.Ext.Applied”=“Yes”): no limitations.
•
D Auxiliary Battery Pack (“V.Bat.Applied” = “Yes” and “V.Bat.Dual” = “Yes”):
no limitations.
•
Default Battery Pack only (“V.Bat.Applied” = “Yes” and “V.Bat.Dual” = “No”): SVC1,
RL1, SVC1+RL1 or RL1+RL2.
•
At Least one SOV Control Output must be enabled.
