Moore Industries STA - 1 Oo2 Redundant Architecture

www.miinet.comMoore Industries-International, Inc.
- 71 -
User’s Manual
225-748-00P
August 2024
www.miinet.com
Programmable RTD, T/C, Ohms, mV and Potentiometer Safety Trip Alarm
STA
TPRG
SECTION 8
1oo2 Redundant Architecture
In this architecture, every component appears twice, and may be applicable for use in SIS
systems up to SIL 3 (Figure 8.3). Advantages are improved reliability of trip action and reduced
vulnerability to a single failure compared to a 1oo1 architecture. The logic in this conguration is
an ‘OR’ statement for the safety function; if either sensor input reaches a trip condition or a fault
relay is activated, the loop or function will reach a tripped state.
Figure 8.3. The STA in a 1oo2 Redundant/Voting Architecture is Applicable for Use in SIS Systems Up to SIL 3.
NC1
CM1
NO1
NC2
CM2
NO2
NC3
CM3
NO3
READY
INPUT TRIP 1 TRIP 2
FAULT
SELECT
DOWN
UP
COM
STA
SAFETY
TRIP
ALARM
TAG
123.95
DEG C
NC1
CM1
NO1
NC2
CM2
NO2
NC3
CM3
NO3
READY
INPUT TRIP 1 TRIP 2
FAULT
SELECT
DOWN
UP
COM
STA
SAFETY
TRIP
ALARM
TAG
DEG C
Sensor Input 1
Sensor Input 2
123.95
Process
Trip 1
Process
Trip 2
Fault
Alarm
Process
Trip 1
Process
Trip 2
Fault
Alarm
Final Element/
Logic Solver