Installation, Operation and Maintenance Manual
MAN712 Rev. 9
June 2021
Working Principle and Detailed Description
Section 5: Working Principle and Detailed Description
31
The AO retransmission works with a precision of 0.5%.
The AO is available only when the External Power Supply is applied
(see Section 5.2.2.3 for details).
The AO is disabled (0 mA transmission) during the execution of the Safety Action and when
the ELBS-20 goes to the SLEEP operating mode.
5.2.4
Digital Input
The ELBS-20 is provided with three configurable opto-isolated Digital Inputs (DI1 – DI3).
Each DI has three terminals. The using of a couple of terminals instead of another
determines the Working Voltage of the DI.
•
”C” and “24/48” terminals: 19.2 - 57.6 V AC/V DC (24 -20% - 48 +20%)
•
“C” and “110” terminals: 57.6 – 121 V AC/V DC (48 +20% - 110 +10%)
The function of each DI is settable. See Section 6.3 for details.
The DIs can be configured to consider the input valid with Voltage applied (present) or not
applied (absent).
When the External Power Supply is not applied and the Battery Pack is present,
do not apply any voltage on the DIs because it causes an unwanted consumption
of the Battery Pack.
5.2.5
Digital Output
The ELBS-20 is provided with 7 Digital Outputs (DO):
•
6x SPST latching relays contacts (D01 – DO6)
•
1x SPDT single side stable relay contacts (DO7)
The function of each DO is settable. See Section 6.2 for details.
D1 – D6 can be configured for working as BREAK (“open circuit” when active) or
MAKE (“short circuit” when active).
When the External Power Supply is not applied, DO7 (single side stable relay)
is not available.
5.2.3
Analog Output (Pressure or Position Retransmission)
The ELBS-20 is provided with a configurable 4 - 20 mA analog output (AO).
The AO can be used for the retransmission of the Pressure or Position measured by the AI.
The AO can accept an external 24 V DC power supply or internally generate the 24 V DC,
necessary for the 4 - 20 mA signal (see Section 9.1 for details about terminals).
24 V DC
±10%
4 - 20 mA
0 V
0 V
EXTERNAL POWER SUPPLY
INTERNAL POWER SUPPLY
4 - 20 mA
LOAD: max 300Ω
LOAD: max 300Ω
