Redundant Control System from ASCO™

ASCO Redundant Control SystemThe ASCO Redundant Control System (RCS) is the only pilot valve system that has no single point of failure that could result in an unwanted closure of the process valve. The Redundant Control System is fit for use in SIL 3 applications and greatly reduces spurious trip rates. RCS achieves a higher level of process safety and reliability by using a redundant, fault tolerant architecture, high diagnostic coverage, and automated testing. A keyed bypass allows on-line maintenance of the RCS without process interruption. The RCS is available in a variety of constructions that provide valve diagnostics through automated, online testing.
 

ASCO's Redundant Control System Provides:

  • Process reliability and valve diagnostics, for safety instrumented applications up to SIL 3
  • The industry's best choice for process valve diagnostics and actuation
  • Complete functional safety with enhanced reliability



 

Features

Redundant Control System Features:

  • High Reliability Architecture – Redundant solenoid configuration (2oo2 / 1oo1HS)
  • Eliminates single point of failure
  • Functional Safety compliant – SIL 3 capable
  • Automated diagnostic capability
  • Online solenoid testing
  • Partial stroke testing
  • Maintenance bypass for online servicing
  • Three pressure switches for feedback
  • Integrated PLC option available
  • Hazardous area & ATEX compliant designs 

 

Specifications

Redundant Control System Specifications:

System TypeRedundant pneumatic pilot valve control system 
Voting Logic2oo2 / 1oo1HS / 2oo3 
Operational ModesEnergize to Trip / De‑energize to Trip
Constructions Normally Closed / Normally Open / Double Acting 
SolenoidsDual or Triple redundant
Feedback Pressure switches / GO Switches 
EnclosureFiberglass / 304 SS / 316 SS
Voltage12–240 V (AC/DC options) 
Safety Integrity SIL 3 capable
Diagnostics Automated SOV & PST testing

Applications

Redundant Control System Applications:

  • Emergency Shutdown Systems
  • Burner Management Systems
  • HIPPS
  • Flaring Systems
  • Isolation Valves
  • Refineries
  • Oil & Gas Production
  • Power Plants
  • Chemical Processing
  • Process Valve Actuation 

Q & A

Q&A Section with Expand/Collapse Icons

Redundant Control System Q & A:

+What is a Redundant Control System (RCS)?
An RCS is a redundant pneumatic pilot valve system designed to control actuated process valves in Safety Instrumented Systems (SIS). It uses multiple solenoid valves in voting architectures to improve reliability and prevent unsafe process conditions.
 
+ What is the purpose of redundancy in RCS?
Redundancy eliminates single points of failure. If one solenoid fails, the system continues to operate safely, preventing nuisance trips or dangerous failures.
 
+ What voting logics are available?
RCS supports 2oo2 (Two out of Two), 1oo1 Hot Standby, and 2oo3 (Two out of Three) voting architectures depending on reliability and safety requirements.
 
+ What is 2oo2 voting?

In 2oo2 architecture, both solenoids must change state for the valve to trip. This reduces false trips and improves availability.

+ What is 1oo1 Hot Standby?

One solenoid operates as primary while the second remains energized as backup, ready to take over if the primary fails.

+ What is 2oo3 voting?

Three solenoids are used, and any two must actuate to trip the valve. This increases fault tolerance and safety availability.

+ Difference between 2oo3 Basic and 2oo3D?

2oo3 Basic has no diagnostics or maintenance bypass. 2oo3D includes GO Switch diagnostics, bypass, and online testing.

+ What diagnostics are available in RCS?

Diagnostics include pressure switch feedback, GO Switch monitoring, solenoid testing, and partial stroke testing.

Downloads

Download ASCO Redundant Control System Brochure 

Talk to one of our experts today at (855) 737-4714, or fill out our online form to learn more.