European Safety Systems Ltd.
Impress House, Mansell Road, Acton, London W3 7QH
www.e2s.com
Tel: +44 (0)208 743 8880
Document No. D190-00-651-IS
Issue 2
06-03-2023
Sheet 8 of 15
12) SIL 2 Instruction/Safety Manual
Figure 9 - The SIL 2 Module monitors the Sounder and interfaces to the customer plant.
Warning
–
To maintain the integrity of the SIL 2 units the system must be installed, commissioned and used within the parameters outlined in this
manual. Failure to comply could result in an unintended unit operation or function.
Warning
–
The unit must be powered in either Standby or Active modes to comply with the SIL 2 approval requirement.
If the power is disrupted the unit must be allowed to go through the commissioning cycle to reset.
Failure to complete the commissioning cycle and continued disruption in the power supply will generate a fault state which will require
the sounder to be reset (see section 16-4).
Warning
–
Only the alarm tones specified in section 15 may be selected for use in SIL2 compliant systems.
SIL 2 System Description
The SIL 2 module monitors the function of the device and provides
feedback to the control panel. A fault condition can be communicated
by two methods:
•
4 wire installation can be seen as per section 16-1.
A SIL 2 system wiring for fault detection in standby and
active mode with independent fault contacts.
•
2 wire installation can be seen as per section 16-2.
A SIL 2 system by the introduction to the monitoring circuit
and linking in an end of line resistor can only register the
fault in standby mode.
13) SIL 2 System Terms and Function
The SIL 2 Sounder Unit Monitors
•
Standby mode and Active mode
•
Health status of power supply
•
Sounder correct function and tone pattern
The SIL 2 sounder operates as part of a SIL 2 system.
The sounder will after commissioning remain powered in
Standby
mode
(reverse polarity) until the sounder is required to operate. When
the signaling device is required to operate the polarity is changed to
normal supply and the sounder will go into
Active mode
where it will
start to sound the correct tone. When periodically testing the system
and sounders operation is put into
Active mode
.
The system panel or PLC will control whether the system is in either
of the main two operational modes.
Standby Mode
–
This is where the power supply polarity is reversed
so negative (
–
ve) is feed to the positive (+) sounder terminal and
positive (+) is feed to the negative (
–
ve) sounder terminal.
In Standby mode the sounder will not sound the tone but the SIL 2 unit
is monitoring power supply and is set-up ready to go to Active (alarm)
mode.
Power relay RLY1-1 will be open whilst SIL 2 relay RLY1-2 will be
closed contact between terminals 1 & 2.
If power is disrupted the SIL 2 unit will go into
Fault mode
, in fault
mode the Power relay RLY1-1 will close whilst SIL 2 relay RLY1-2 will
become open circuit between terminals 1 & 2.
Active Mode
–
This is where the power is in normal polarity, positive
(+) supplied to the positive (+) sounder terminal and negative (
–
ve) is
supplied to the negative (
–
ve) sounder terminal.
In Active mode the alarm horn sounder will output the selected alarm
tone. The SIL 2 module checks for the correct alarm tone output and
the functionality of the alarm tone signal generation process.
Power relay RLY1-1 will be open whilst SIL 2 relay RLY1-2 will be
closed contact between terminals 1 & 2.
The SIL 2 unit will also check for signal polarity.
If a fault is found the SIL 2 unit will go into
Fault mode
.
If power is disrupted the SIL 2 unit will go into
Fault mode
, in fault
mode the Power relay RLY1-1 will close whilst SIL 2 relay RLY1-2 will
become open be circuit between terminals 1 & 2.
J3 HEADER PIN
