SIL4 ProSafe-SLS

ProSafe-SLS Safety Instrumented System

ProSafe-SLS is Yokogawa's solid-state, hard-wired safety instrumented system designed to meet the highest safety integrity requirements. The product line meets specific requirements for individual safety instrumented systems and offers all safety integrity levels (SIL 3-4) for the oil and gas, petrochemical, chemical, nuclear and conventional power industries.

ProSafe-SLS safety instrumented system is also fully integrated with Yokogawa's CENTUM VP process control system as well as the FAST/TOOLS SCADA software package.

The modular design of the ProSafe-SLS safety system allows for building all kinds of applications, ranging from small HIPS systems to large ESD and F&G systems while maintaining the fastest possible response time to follow any process demand.

ProSafe-SLS provides the ultimate SIS solution when safety allows no compromise.

Prosafe SLSSafety-by-Design

The ProSafe-SLS is a safety instrumented system that was designed for applications that require the highest Safety Integrity Levels (SIL 3 & 4).

It employs solid-state elements to process the functional logic. This technology is capable of executing all typical safety tasks, featuring Non-Safety-Critical functions such as interfacing with a Human Machine Interface, Process Control System, Sequence of Event Recording, or SCADA system.

The sophisticated design and superior safety performance have created the safety reference standard for solid-state safety instrumented systems.

A radical safety achievement is the elimination of software for an operating system and for self-diagnostics. Instead, a unique inherent self-test technology is employed, throughout all safety-related parts of the ProSafe-SLS system.


System Structure

A system with a modular approach

Prosafe SLS
8-channel digital input module

The modules that are used to build a system solution are grouped in various categories as summarized below:

  • Input modules
  • Logic & Timer modules
  • Output modules
  • Power & Clock modules
  • Auxiliary modules
  • Communication & Interface modules

Interconnection wiring actually programs the application into the system.

The ProSafe SLS Safety Instrumented System Range

Yokogawa covers the spectrum of requirements for today’s safety systems with two product lines, ProSafe-SLS and ProSafe-RS, each geared to the needs of specific safety applications. For the highest- integrity, SIL 4-rated applications, the ProSafe-SLS platform offers a superior solution - for the spectrum of applications in oil and gas, petrochemical and chemical, and conventional and nuclear power industries, including:

  • Emergency-shut-down systems in safety-critical process units
  • Environmental and asset protection systems
  • Burner management systems for incinerators, furnaces and boilers
  • Compressor protection systems for rotating and piston type compressors
  • Process and emergency shutdown systems on offshore platforms and FPSO’s
  • High integrity protection systems for critical
    processes and pipeline protection
  • Wellhead protection systems and sub-sea
  • Liquefied natural gas (LNG) storage and loading
  • High-integrity protection systems in chemical
    process plants as well as applications where
    previous-generation relay -based systems are
    to be upgraded.


  • CENTUM CS 3000 replaces legacy system at Paris's largest waste to energy plant
  • Exaquantum is used to calculate plant performance and generate the reports needed to optimize operations and demonstrate regulatory compliance

Recently, several ARC Advisory Group analysts and management team members had a chance to sit down with the new Yokogawa President and COO, Mr. Takashi Nishijima, and several other top Yokogawa executives to discuss the company's burgeoning presence in the worldwide upstream and midstream oil & gas industry.


Yokogawa has come a long way in making its message clear to the world of process automation. Last year, the company embarked on a full-scale global marketing campaign to make customers aware of the company's focus on system reliability, security, dependability, and robustness. Dubbed "Vigilance", the campaign created a unified message for the company and greatly helped expand awareness of the Yokogawa brand and corporate philosophy.

Yokogawa Technical Report

There are already safety systems on the market that have achieved safety integrity level SIL3 of the functional safety standard, IEC61508. However, most of them have achieved SIL3 by conversion of modules into dual-redundant or triplex form.

Yokogawa Technical Report

Environment and safety are major topics on a global scale in recent times. As symbolized by the effectuation of the Kyoto Protocol, an interest in preserving the environment is growing worldwide, and there is also a tendency to criticize more severely, occurrences of industrial accidents that are accompanied by environmental contamination or which may cause damage, etc., to residents in the surrounding areas.


August 2006

Many published papers discuss the benefits of subsea HIPPS and many studies show the potential cost-benefit analysis of this technology in deepwater applications. An internet search for subsea HIPPS is informative; however, little appears that discusses the systems already delivered and operating successfully.


General Specifications



Yokogawa South Africa was appointed to design, supply and commission the Integrated Control and Safety System (ICSS) as well as the overall Terminal Management System at Sunrise Energy’s liquid petroleum gas (LPG) Import Terminal, the largest on- and offshore open-access LPG import terminal facility in Africa. Yokogawa’s Terminal Management System, Terminal Logistic Suite VP (TLSVP), was designed and developed to meet the exacting operational demands and logistic needs in terminals. Yokogawa’s experienced engineering resources ensured the project was successfully delivered, enabling Sunrise Energy to provide accurate mass balances and efficient terminal operations to its customers.

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