320-321 / 1143
The SIS is comprised of:
2oo3 architecture, for the pressure sensor sub system;
set to initiate a trip signal;
to the logic solver when 70barg is detected from upstream. The trip signal from the logic
solver de-energises;
either of the two-solenoid valves to relieve the air pressure in the pneumatic actuator,
which will drive the valve closed (Air Fail Closed) within a total response time of 3
seconds;
Sensors – Smart Pressure Transmitter (two wire 4-20mA) voted 2oo3;
Logic Solver – Solid State triplicated fail-safe logic with Namur 43 compliant trip amplifiers;
Solenoid Valves – 3 way 2 position normally closed 24 vdc Electro Magnetic with spring
return voted 1oo2 and
Final Element Valve – Mokveld Valve B.V., RZD-R including M-series actuator.
SIS